Monday, September 29, 2014

Hubble Vision: Galaxy DDO 68 – Young Or Old?

Hubble Vision: Galaxy DDO 68 – Young Or Old?:

Image credit: NASA & ESA


Image credit: NASA & ESA
Only astronomers know for sure… Or do they? In this assembly of images taken with Hubble’s Advanced Camera for Surveys, scientists have utilized both visible and infrared light to survey a most unusual galaxy. When looking for a newly formed galaxy in our “cosmic neighborhood”, they spied DDO 68 (a.k.a. UGC 5340). Normally to witness galactic evolution, we have to look over great distances to see back in time… but this particular collection of gas and stars seems to break the rules!

Researching galactic evolution isn’t a new concept. Over the last few decades astronomers have increased our understanding of how galaxies change with time. One of the most crucial players in this game has been the NASA/ESA Hubble Space Telescope. Through its eyes, scientists can see over almost incomprehensible distances – studying light that has taken billions of years to reach us. We are essentially looking back in time.

While this is great news on its own, studying progressively younger galaxies can sometimes pose more questions than it answers. For example, all the newly created galaxies reside a huge distance from us and thereby appear small and faint when imaged. On the other side of the coin, galaxies which are close to us appear to be far more mature.

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This video begins with a ground based view of the night sky, before zooming in on dwarf galaxy DDO 68 as the NASA/ESA Hubble Space Telescope sees it. This ragged collection of stars and gas clouds looks at first glance like a recently-formed galaxy in our own cosmic neighbourhood. But, is it really as young as it looks? Credit: NASA/ESA
DDO 68, imaged here by the NASA/ESA Hubble Space Telescope, would seem to be the best example of a nearby newly-formed galaxy. Just how nearby? Estimates place it at about 39 million light years distant. While this might seem like a very long way, it is still roughly 50 times closer than other galactic examples. Studying galaxies of different ages is important to our understanding of how the Universe works. Astronomers have discovered that young galaxies are quite different than those which have aged. In this case, DDO 68 gives off the appearance of being young. These findings come from examining its structure, appearance and composition. However, researchers question their findings. It is possible this galaxy may be considerably older than initial findings indicate.

“All of the available data are consistent with the fact that DDO 68 is a very rare candidate for young galaxies.” says S. A. Pustilnik (et al). “The bulk of its stars were formed during the recent (with the first encounter about 1 Gyr ago) merger of two very gas-rich disks.”

These common events – mergers and collisions – are part of galactic life and are generally responsible for older galaxies being more bulky. These “senior citizens” are normally laced with a wide variety of stellar types – young, old, large and small. The chemistry is also different, too. Very young galaxies are rich in hydrogen and helium, making them tantalizingly similar in composition to the primordial matter created by the Big Bang. Older galaxies have more experiences. Numerous stellar events have happened within them over their lifetimes, making them rich in heavy elements. This is what makes DDO 68 very exciting! It is the best local candidate found so far to be low in heavier elements.

“DDO 68 (UGC 5340) is the second most metal-poor star-forming galaxy,” explains Pustilnik. “Its peculiar optical morphology and its HI distribution and kinematics are indicative of a merger origin. We use the u, g, r, and i photometry based on the SDSS images of DDO 68 to estimate its stellar population ages.”

Step into the light? You bet. The Hubble observations were meant to examine the properties of this mysterious galaxy’s light – determine whether or not it contains any older stars. If they are discovered, which seems to be the case, this would disprove the theory that DDO 68 is singularly comprised of younger stars. If not, it will validate the unique nature of this nearby neighbor. While more computer modeling and studies are needed, we can still enjoy this incredible look at another cosmic enigma!

Original Story Source: A Galaxy Of Deception – Hubble/ESA


Tagged as: DDO 68, galactic evolution, Hubble Telescope Images

Posted by Nelio Inacio at 3:46 PM 0 comments

India’s Bargain Mars Spacecraft Cost Less Than Many Space Movies

India’s Bargain Mars Spacecraft Cost Less Than Many Space Movies:

Artist's conception of India’s Mars Orbiter Mission (MOM). Credit ISRO


Artist’s conception of India’s Mars Orbiter Mission (MOM). Credit ISRO
India achieved a remarkable feat earlier this week — the nation became only one of a handful of countries to successfully send a probe to Mars. The $75 million mission has been hailed as an achievement by NASA and other space experts from around the world.

Just how remarkable is this bargain mission? As a tweet from travel writer Jon Tindale pointed out, MOM cost less than the 2000 Gary Sinise movie Mission To Mars. (Note that we came up with a different dollar figure below.)

Just for fun, we’ve compared MOM to several space movies below. All dollar figures are adjusted for inflation from budgets listed in the Internet Movie Database.

Avatar: $263 million ($237 million in 2009 dollars)

Wall-E: $199 million ($180 million in 2008 dollars)

The Fifth Element: $138 million ($93 million in 1997 dollars)

Mission to Mars: $124 million ($90 million in 2000 dollars)

Elysium: $117 million ($115 million in 2013 dollars)

Star Trek: The Motion Picture: $115 million ($35 million in 1979 dollars)

Gravity: $102 million ($100 million in 2013 dollars)

Apollo 13: $101.5 million ($62 million in 1995 dollars)

Dune (1984): $92 million ($40 million in 1984 dollars)

Close Encounters of the Third Kind: $76 million ($19.4 million in 1977 dollars)

2001: A Space Odyssey: $72 million ($10.5 million in 1968 dollars)

Mars Orbiter Mission: $70 million (2014 dollars)

The Right Stuff: $65 million ($27 million in 1983 dollars)

Serenity: $49 million ($40 million in 2005 dollars)

Star Wars (1977): $43 million ($11 million in 1977 dollars)

Outland: $42 million ($16 million in 1981 dollars)

Alien: $36 million ($11 million in 1979 dollars)

War of the Worlds (1953): $18 million ($2 million in 1953 dollars)

Silent Running: $6.2 million ($1.1 million in 1972 dollars)

Moon: $5.5 million ($5 million in 2009 dollars)

Apollo 18: $5.3 million ($5 million in 2011 dollars)


Tagged as: Mars Orbiter Mission, space movies

Posted by Nelio Inacio at 3:46 PM 0 comments

Have Astronomers Seen a Forming Planet in Action?

Have Astronomers Seen a Forming Planet in Action?:

Image at 7 mm wavelength of the dusty disk around the star HD 169142 obtained with the Very Large Array (VLA) at 7 mm wavelength. The positions of the protoplanet candidates are marked with plus signs (+) (Osorio et al. 2014, ApJ, 791, L36). The insert in the upper right corner shows, at the same scale, the bright infrared source in the inner disk cavity, as observed with the Very Large Telescope (VLT) at 3.8 micron wavelength (Reggiani et al. 2014, ApJ, 792, L23).


Image of the dusty disk around the star HD 169142 obtained with the Very Large Array. The positions of the protoplanet candidates are marked with plus signs (Osorio et al. 2014, ApJ, 791, L36). The insert in the upper right corner shows the bright infrared source in the inner gap, as observed with the Very Large Telescope. (Reggiani et al. 2014, ApJ, 792, L23).
Huge disks of dust and gas encircle many young stars. Some contain circular gaps — likely the result of forming planets carving out cavities along their orbital paths — that make the disks look more like ripples in a pond than flat pancakes.

But astronomers know only a few examples, including the archetypal disk surrounding Beta Pictoris, of this transitional stage between the original disk and the young planetary system. And they have never spotted a forming planet.

Two independent research teams think they’ve observed precisely this around the star HD 169142, a young star with a disk that extends up to 250 astronomical units (AU), roughly six times greater than the average distance from the Sun to Pluto.

Mayra Osorio from the Institute of Astrophysics of Andalusia in Spain and colleagues first explored HD 169142’s disk with the Very Large Array (VLA) in New Mexico. The 27 radio dishes configured in a Y-shape allowed the team to detect centimeter-sized dust grains. Then combining their results with infrared data, which traces the presence of microscopic dust, the group was able to see two gaps in the disk.

One gap is located between 0.7 and 20 AU, and the second larger gap is located between 30 and 70 AU. In our Solar System the first would begin at the orbit of Venus and end at the orbit of Uranus, while the second would begin at the orbit of Neptune, pass Pluto’s orbit, and extend beyond.

“This structure already suggested that the disk was being modified by two planets or sub-stellar objects, but, additionally, the radio data reveal the existence of a clump of material within the external gap, located approximately at the distance of Neptune’s orbit, which points to the existence of a forming planet,” said Mayra Osorio in a news release.

Maddalena Reggiani from the Institute for Astronomy in Zurich and colleagues then tried to search for infrared sources in the gaps using the Very Large Telescope. They found a bright signal in the inner gap, which likely corresponds to a forming planet or a young brown dwarf, an object that isn’t massive enough to kick start nuclear fusion.

The team was unable to confirm an object in the second gap, likely due to technical limitations. Any object with a mass less than 18 times Jupiter’s mass will remain hidden in the data.

Future observations will shed more light on the exotic system, hopefully allowing astronomers to better understand how planets first form around young stars.

Both papers have been published in the Astrophysical Journal Letters.


Tagged as: exoplanets, Planetary Disks, protoplanets, Very Large Array, Very Large Telescope

Posted by Nelio Inacio at 3:45 PM 0 comments

Busy Spaceport: There are Now Five Spaceships Parked at the Space Station

Busy Spaceport: There are Now Five Spaceships Parked at the Space Station:

Five spacecraft are parked at the International Space Station including the Soyuz TMA-14M and Dragon which docked this week. Credit: NASA


Five spacecraft are parked at the International Space Station including the Soyuz TMA-14M and Dragon which docked this week. Credit: NASA
Mars isn’t the only place in the Solar System that was busy this week with arriving spacecraft. While NASA’s MAVEN and ISRO’s MOM arrived in orbit around the Red Planet, the International Space Station also welcomed two arriving spacecraft, bringing the total of docked ships at the ISS to five.


Screenshot from NASA TV of the Soyuz-TMA14M arriving with just one solar panel deployed.


Screenshot from NASA TV of the Soyuz-TMA14M arriving with just one solar panel deployed.
Last night, the Expedition 41/42 crew arrived — peeling in on one solar panel on their Soyuz TMA-14M — with the first female cosmonaut to be part of an ISS crew, Elena Serova along with her crewmates cosmonaut Alexander Samokutyaev, and NASA astronaut Barry Wilmore. They took the Soyuz “fast track,” arriving at the station in just under six hours after launch. One of the craft’s solar panels jammed and couldn’t deploy, but the crew docked to Poisk docking compartment without indecent.

The arrival of Wilmore, Samokutyaev and Serova returns the station’s crew complement to six. Already on board are Commander Max Suraev of Roscosmos, Reid Wiseman of NASA and Alexander Gerst of the European Space Agency. They have been aboard the complex since May.

Suraev, Wiseman and Gerst will return home in November. At that time, Wilmore will become commander of the station for Expedition 42, and the remainder of the Expedition 42 crew will arrive in a new Soyuz.

Earlier this week, on September 23, the SpaceX Dragon capsule arrived with over 2.5 tons of science experiments and supplies for the crew.

Also docked to the space station is the Soyuz ship that will take Suraev, Wiseman and Gerst home, a Progress resupply ship and the European ATV-5 supply ship.

There are two more cargo missions targeted to launch to the space station before the end of the year. Orbital Sciences just announced October 20 as the next launch date for their Cygnus commercial space freighter. It will occupy the same Harmony node port as Dragon when it leaves in a few weeks. When Cygnus vacates the Harmony node port, SpaceX CRS-5 will replace it in December.

Tagged as: ATV-5, Dragon capsule, international space station, Soyuz, SpaceX

Posted by Nelio Inacio at 3:44 PM 0 comments

ESA’s Rosetta Mission sets November 12th as the Landing Date for Philae

ESA’s Rosetta Mission sets November 12th as the Landing Date for Philae:

Illustration of the Rosetta Missions Philae lander on final approach to a comet surface. The date is now set for landing, November 12. (Photo: ESA)


Illustration of the Rosetta Missions Philae lander on final approach to a comet surface. The date is now set for landing, November 12. (Photo: ESA)
ESA Rosetta mission planners have selected November 12th, one day later than initially planned, for the historic landing of Philae on a comet’s surface. The landing on 67P/Churyumov-Gerasimenko will be especially challenging for the washing machine-sized lander. While mission scientists consider their choice of comet for the mission to be an incredibly good one for scientific investigation and discovery, the irregular shape and rugged terrain also make for a risky landing. The whole landing is not unlike the challenge one faces in shooting a moving target in a carnival arcade game; however, this moving target is 20 kilometers below and it is also rotating.



At  8:35 GMT (3:35 AM EST), the landing sequence will begin with release of Philae by Rosetta at an altitude of 20 kilometers above the comet. The expected time of touchdown is seven hours later – 15:35 GMT (10:35 AM EST). During the descent, Philae’s ROLIS camera will take a continuous series of photos. The comet will complete more than half a rotation during the descent; comet P67’s rotation rate is 12.4 hours. The landing site will actually be on the opposite side of the comet when Philae is released and will rotate around, and if all goes as planned, meet Philae at landing site J.

Before November 12th, mission planners will maintain the option of landing at Site C. If the alternate site is chosen, the descent will begin at 13:04 GMT also on November 12 but from an altitude of 12.5 kilometers, a 4 hour descent time.

NAVCAM image of the comet on 21 September, which includes a view of primary landing site J. Click for more details and link to context image. (Credits: ESA/Rosetta/NAVCAM)


NAVCAM image of the comet on 21 September, which includes a view of primary landing site J. Click for more details and link to context image. (Credits: ESA/Rosetta/NAVCAM)
Rosetta will eject Philae with an initial velocity of approximately 2 1/2  kilometers per hour. Because the comet is so small, its gravity will add little additional speed to Philae as it falls to the surface. Philae is essentially on a ballistic trajectory and does not have any means to adjust its path.

The actions taken by Philae’s onboard computer begin only seconds from touchdown. It has a landing propulsion system but unlike conventional systems that slow down the vehicle for soft landing, Philae’s is designed to push the lander snugly onto the comet surface. There is no guarantee that Philae will land on a flat horizontal surface. A slope is probably more likely and the rocket will force the small lander’s three legs onto the slope.

A model of the comet P67/Churyumov-Gerasimenko created using images from the Rosetta OSIRIS narrow field camera. (Credit: ESA)


A model of the comet P67/Churyumov-Gerasimenko created using images from the Rosetta OSIRIS narrow field camera. Mouse click on the image to start the animated GIF. (Credit: ESA)
Landing harpoons will be fired that are attached to cables that will be pulled in to also help Philae return upright and attach to the surface. Philae could actually bounce up or topple over if the rocket system and harpoons fail to do their job.

The Philae Lander anchoring harpoon with the integrated MUPUS-accelerometer and temperature sensor. (Credit: "Philae Lander Fact Sheet", ESA)


The Philae Lander anchoring harpoon with the integrated MUPUS-accelerometer and temperature sensor. (Credit: “Philae Lander Fact Sheet”, ESA)
However, under each of the three foot pads, there are ice screws that will attempt to drill and secure Philae to the surface. This will depend on the harpoons and/or rockets functioning as planned, otherwise the action of the drills could experience resistance from hard ground and simply push the lander up rather than secure it down. Philae also has a on-board gyro to maintain its attitude during descent, and an impact dampener on the neck of the vehicle which attaches the main body to the landing struts.

Ten landing sites were picked, then down-selected to five, and then finally on September 15th, they selected Site J on the head of the smaller lobe – the head of the rubber duck, with site C as a backup. Uncertainty in the release and the trajectory of the descent to the comet’s surface means that the planners needed to find a square kilometer area for landing. But comet 67P/Churyumov-Gerasimenko simply offered no site with that much flat area clear of cliffs and boulders. Philae will be released to land at Site J which offers some smooth terrain but only about a quarter of the area needed to assure a safe landing. Philae could end up landing on the edge of a cliff or atop a large boulder and topple over.

A 'color' view of Comet 67P, from a September 24, 2014 NavCam image. Credits: ESA/Rosetta/NavCam - Processing by Elisabetta Bonora & Marco Faccin.


A ‘color’ view of Comet 67P, from a September 24, 2014 NavCam image. Credits: ESA/Rosetta/NavCam – Processing by Elisabetta Bonora & Marco Faccin.
The Rosetta ground control team will have no means of controlling and adjusting Philae during the descent. This is how it had to be because the light travel time for telecommunications from the spacecraft to Earth does not permit real-time control. The execution time and the command sequence will be delivered to Rosetta days before the November 12th landing. And ground control must maneuver Rosetta with Philae still attached to an exact point in space where the release of Philae must take place. Any inaccuracy in the initial release point will be translated all the way down to the surface and Philae would land some undesired distance away from Site J. However, ground controllers have a month and a half to practice simulations of the landing many times over with a model of the comet’s nucleus. With practice and more observational data between now and the landing, the initial conditions and model of the comet in the computer simulation will improve and raise the likelihood of a close landing to Site J.

Previous Universe Today articles on Rosetta’s Philae:

How do you land on a comet? Very carefully.

Rosetta’s Philae Lander: A Swiss Army Knife of Scientific Instruments

Comet’s Head Selected as Landing Site for Rosetta’s Historic Philae Lander


Tagged as: esa, historic, lander, landing, P67/Churyumov-Gerasimenko, philae, rosetta

Posted by Nelio Inacio at 3:44 PM 0 comments

MOM Eyes the Limb of Mars after History Creating Arrival

MOM Eyes the Limb of Mars after History Creating Arrival:

ISRO's Mars Orbiter Mission captures the limb of Mars with the Mars Color Camera from an altitude of 8449 km soon after achieving orbit on Sept. 23/24, 2014. . Credit: ISRO


ISRO’s Mars Orbiter Mission captures the limb of Mars with the Mars Color Camera from an altitude of 8449 km soon after achieving orbit on Sept. 23/24, 2014 . Credit: ISRO
India’s maiden interplanetary voyager, the Mars Orbiter Mission (MOM) has transmitted a breathtaking new image eyeing the limb of Mars and its atmosphere against the blackness of space.

The beautiful Martian image is only MOM’s second since successfully braking into orbit during the ‘history creating’ insertion maneuver days ago on Sept. 23/24.

The MOM orbiter was designed and developed by the Indian Space Research Organization (ISRO), India’s space agency, which released the image on Sept 25, about a day after MOM arrived.

The limb image was taken using MOM’s Mars Color Camera (MCC) from an altitude of 8449 kilometers and shows more of an ‘Orange Planet’ rather than a ‘Red Planet.’

“A shot of Martian atmosphere. I’m getting better at it. No pressure,” tweeted ISRO at MOM’s newly established twitter account after entering orbit.

The image has a spatial resolution of 439 meters and is centered around Lat: 20.01N and Lon:31.54E.

MOM’s goal is to study Mars atmosphere , surface environments, morphology, and mineralogy with a 15 kg (33 lb) suite of five indigenously built science instruments. It will also sniff for methane, a potential marker for biological activity.

“The view is nice up here,” ISRO tweeted.

MOM’s first image taken shortly after orbital arrival showed a heavily cratered region of the Red Planet taken by the MCC tri-color camera from a slightly lower altitude of 7300 kilometers with a spatial resolution of 376 meters.

ISRO's Mars Orbiter Mission captures its first image of Mars from a height of 7300 km. Credit: ISRO


ISRO’s Mars Orbiter Mission captures its first image of Mars from a height of 7300 km. Credit: ISRO
Following MOM’s successful Mars Orbital Insertion (MOI) maneuver, India became the newest member of an elite club of only four entities who have launched probes that successfully investigated Mars – following the Soviet Union, the United States and the European Space Agency (ESA).

Read my complete MOM meets Mars arrival story – here.

MOM is now circling Mars in a highly elliptical orbit whose nearest point to Mars (periapsis) is at 421.7 km and farthest point (apoapsis) at 76,993.6 km. The inclination of orbit with respect to the equatorial plane of Mars is 150 degree, as intended, ISRO reports.

The $73 million mission is expected to last at least six months.

MOM’s success follows closely on the heels of NASA’s MAVEN orbiter which also successfully achieved orbit barely two days earlier on Sept. 21 and could last 10 years or more.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer


Tagged as: indian space program, Indian Space Research Organization, ISRO, Mars, Mars MAVEN, Mars Orbiter Mission, MAVEN, MOM, red planet

Posted by Nelio Inacio at 3:43 PM 0 comments

PanSTARRS K1, the Comet that Keeps Going and Going and Going

PanSTARRS K1, the Comet that Keeps Going and Going and Going:

Comet C/2012 K1 PANSTARRS photographed on September 26, 2014 by Rolando Ligustri. Like most comets, we see two tails. K1's dust tails points off to the left, it's gas or ion tail to the right. Credit: Rolando Ligustri


Comet C/2012 K1 PanSTARRS photographed on September 26, 2014. Two tails are seen – a dust tail points off to the left and the gas or ion tail to the right. Copyright: Rolando Ligustri
Thank you K1 PanSTARRS for hanging in there!  Some comets crumble and fade away. Others linger a few months and move on. But after looping across the night sky for more than a year, this one is nowhere near quitting. Matter of fact, the best is yet to come.

This new visitor from the Oort Cloud making its first passage through the inner solar system, C/2012 K1 was discovered in May 2012 by the Pan-STARRS 1 survey telescope atop Mt. Haleakala in Hawaii at magnitude 19.7. Faint! On its the inbound journey from the Oort Cloud, C/2012 K1 approached with an orbit estimated in the millions of years. Perturbed by its interactions with the planets, its new orbit has been reduced to a mere  ~400,000 years.  That makes the many observing opportunities PanSTARRS K1 has provided that much more appreciated. No one alive now will ever see the comet again once this performance is over.

Comet C/2012 K1 PanSTARRS' changing appearance over the past year. Credit upper left clockwise: Carl Hergenrother, Damian Peach, Chris Schur and Rolando Ligustri


Comet C/2012 K1 PanSTARRS’ changing appearance over the past year. Credit upper left clockwise: Carl Hergenrother, Damian Peach, Chris Schur and Rolando Ligustri
Many amateur astronomers first picked up the comet’s trail in the spring of 2013 when it had brightened to around magnitude 13.5. My observing notes from June 2, 2013, read:

“Very small, about 20 arc seconds in diameter. Pretty faint at ~13.5 and moderately condensed but not too difficult at 142x . Well placed in Hercules.” Let’s just say it was a faint, fuzzy blob.

K1 PanSTARRS slowly brightened in Serpens last fall until it was lost in evening twilight. Come January this year it returned to the morning sky a little closer to Earth and Sun and a magnitude brighter. As winter snow gave way to frogs and flowers, the comet rocketed across Corona Borealis, Bootes and Ursa Major. Its fat, well-condensed coma towed a pair of tails and grew bright enough to spot in binoculars at magnitude 8.5 in late May.

Skywatchers can find C/2012 K1 PanSTARRS in the morning just in Hydra-Puppis just before dawn. The map shows its location daily with stars to magnitude 8.5. The numbers next to some stars are standard Flamsteed atllas catalog numbers. Source: Chris Marriott's SkyMap


Skywatchers can find C/2012 K1 PanSTARRS in the morning sky in the Hydra and Puppis just before dawn when it’s highest in the southeastern sky. The map shows its location daily with stars to magnitude 8.5. The numbers next to some stars are standard Flamsteed atlas catalog numbers. Click for a larger version. Source: Chris Marriott’s SkyMap
By July, it hid away in the solar glare a second time only to come back swinging in September’s pre-dawn sky.  Now in the constellation Hydra and even closer to Earth, C/2012 K1 has further brightened to magnitude 7.5. Though low in the southeast at dawn, I was pleasantly surprised to see it several mornings ago. Through my 15-inch (37-cm) reflector at 64x I saw a fluffy, bright coma punctuated by a brighter, not-quite-stellar nucleus and a faint tail extending 1/4º to the northeast.

Mid-northern observers can watch the comet’s antics through mid-October. From then on, K1 will only be accessible from the far southern U.S. and points south as it makes the rounds of Pictor, Dorado and Horologium. After all this time you might think the comet is ready to depart Earth’s vicinity. Not even. C/2012 K1 will finally make its closest approach to our planet on Halloween (88.6 million miles – 143 million km) when it could easily shine at magnitude 6.5, making it very nearly a naked-eye comet.

PanSTARRS K1’s not giving up anytime soon. Southern skywatchers will keep it in view through the spring of 2015 before it returns to the deep chill from whence it came. After delighting skywatchers for nearly two years, it’ll be hard to let this one go.


Tagged as: C/2012 K1 PANSTARRS, coma, comet, Oort cloud

Posted by Nelio Inacio at 3:42 PM 0 comments

Stunning Astrophoto: Milky Way Over Fünfländerblick

Stunning Astrophoto: Milky Way Over Fünfländerblick:

'Fu?nfla?nderblick Milchstrasse,' the Milky Way over a dark country sky in Switzerland. Credit and copyright: Christian Kamber.


‘Fu?nfla?nderblick Milchstrasse,’ the Milky Way over a dark country sky in Switzerland. Credit and copyright: Christian Kamber.
Hey, it’s #MilkyWayMonday! This gorgeous photo of the Milky Way was taken by astrophotographer Christian Kamber near Fu?nfla?nderblick, Switzerland (you can see the region on a map here). This is a stack of 20 shots, made with Deep Sky Stacker and Photoshop.

Lovely!


Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Tagged as: #milkywaymonday, Astrophoto, milky way

Posted by Nelio Inacio at 3:41 PM 0 comments

Behold: 100 Planetary Nebulas

Behold: 100 Planetary Nebulas:

100 colorful planetary nebulae, at apparent size relative to one another. Image processing and collection by Judy Schmidt.


100 colorful planetary nebulae, at apparent size relative to one another. Image processing and collection by Judy Schmidt.
If you like planetary nebulas, you’re in luck. Multimedia artist Judy Schmidt has put together an amazing collection of 100 of these colorful glowing shells of gas and plasma, all at apparent size relative to one another. There’s even a giant-sized 10,000 pixel-wide version available on Flickr.

How many of these planetary nebulae can you identify?

Judy explained her inspiration for putting together this wonderful ‘poster':

Inspired by insect illustration posters, this is a large collage of planetary nebulas I put together bit by bit as I processed them. All are presented north up and at apparent size relative to one another–I did not rotate or resize them in order to satisfy compositional aesthetics (if you spot any errors, let me know). Colors are aesthetic choices, especially since most planetary nebulas are imaged with narrowband filters.
Planetary nebulae are formed by certain types of stars at the end of their lives, and actually have nothing to do with planets. They were given the confusing name 300 years ago by William Herschel because in early, rudimentary telescopes, the puffed out balls of gas looked like planets.

Our own Sun will likely undergo a similar process, but not for another 5 billion years or so.

You can see more of Judy’s work at her website “Geckzilla” or Flickr page.

Tagged as: Judy Schmidt, Planetary Nebula

Posted by Nelio Inacio at 3:41 PM 0 comments

Cold Atom Laboratory Chills Atoms to New Lows

Cold Atom Laboratory Chills Atoms to New Lows: Artist's concept of an atom chip for use by NASA's Cold Atom Laboratory (CAL) Artist's concept of an atom chip for use by NASA's Cold Atom Laboratory (CAL) aboard the International Space Station. CAL will use lasers to cool atoms to ultracold temperatures. Image Credit: NASA
› Full image and caption


September 26, 2014

NASA's Cold Atom Laboratory (CAL) mission has succeeded in producing a state of matter known as a Bose-Einstein condensate, a key breakthrough for the instrument leading up to its debut on the International Space Station in late 2016.

A Bose-Einstein condensate (BEC) is a collection of atoms in a dilute gas that have been lowered to extremely cold temperatures and all occupy the same quantum state, in which all of the atoms have the same energy levels. At a critical temperature, atoms begin to coalesce, overlap and become synchronized like dancers in a chorus line. The resulting condensate is a new state of matter that behaves like a giant -- by atomic standards -- wave.

"It's official. CAL's ground testbed is the coolest spot at NASA's Jet Propulsion Laboratory at 200 nano-Kelvin [200 billionths of 1 Kelvin], "said Cold Atom Laboratory Project Scientist Rob Thompson at JPL in Pasadena, California. "Achieving Bose-Einstein condensation in our prototype hardware is a crucial step for the mission."

Although these quantum gases had been created before elsewhere on Earth, the Cold Atom Laboratory will explore the condensates in an entirely new regime: The microgravity environment of the space station. It will enable groundbreaking research in temperatures colder than any found on Earth.

CAL will be a facility for studying ultra-cold quantum gases on the space station. In the station's microgravity environment, interaction times and temperatures as low as one picokelvin (one trillionth of one Kelvin, or 293 trillion times below room temperature) should be achievable. That's colder than anything known in nature, and the experiments with CAL could potentially create the coldest matter ever observed in the universe. These breakthrough temperatures unlock the potential to observe new quantum phenomena and test some of the most fundamental laws of physics.

First observed in 1995, Bose-Einstein condensation has been one of the "hottest" topics in physics ever since. The condensates are different from normal gases; they represent a distinct state of matter that starts to form typically below a millionth of a degree above absolute zero, the temperature at which atoms have the least energy and are close to motionless. Familiar concepts of "solid," "liquid" and "gas" no longer apply at such cold temperatures; instead, atoms do bizarre things governed by quantum mechanics, such as behaving as waves and particles at the same time.

Cold Atom Laboratory researchers used lasers to optically cool rubidium atoms to temperatures almost a million times colder than that of the depths of space. The atoms were then magnetically trapped, and radio waves were used to cool the atoms 100 times lower. The radiofrequency radiation acts like a knife, slicing away the hottest atoms from the trap so that only the coldest remain.

The research is at the point where this process can reliably create a Bose-Einstein condensate in just seconds.

"This was a tremendous accomplishment for the CAL team. It confirms the fidelity of the instrument system design and provides us a facility to perform science and hardware verifications before we get to the space station," said CAL Project Manager Anita Sengupta of JPL.

While so far, the Cold Atom Laboratory researchers have created Bose-Einstein condensates with rubidium atoms, eventually they will also add in potassium. The behavior of two condensates mixing together will be fascinating for physicists to observe, especially in space.

Besides merely creating Bose-Einstein condensates, CAL provides a suite of tools to manipulate and probe these quantum gases in a variety of ways. It has a unique role as a facility for the atomic, molecular and optical physics community to study cold atomic physics in microgravity, said David Aveline of JPL, CAL ground testbed lead.

"Instead of a state-of-the-art telescope looking outward into the cosmos, CAL will look inward, exploring physics at the atomic scale," Aveline said.

JPL is developing the Cold Atom Laboratory sponsored by the International Space Station Program at NASA's Johnson Space Center in Houston.

The Space Life and Physical Sciences Division of NASA's Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington manages the Fundamental Physics Program.

For more information about the Cold Atom Laboratory visit:

http://coldatomlab.jpl.nasa.gov/

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

2014-325

Posted by Nelio Inacio at 3:40 PM 0 comments

Rosetta to Deploy Lander on November 12

Rosetta to Deploy Lander on November 12: Image depicts the primary landing site on comet 67P/Churyumov-Gerasimenko Image depicts the primary landing site on comet 67P/Churyumov-Gerasimenko chosen for the European Space Agency's Rosetta mission. Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
› Full image and caption


September 26, 2014

The European Space Agency's Rosetta mission will deploy its lander, Philae, to the surface of comet 67P/Churyumov-Gerasimenko on Nov. 12.

Rosetta is an international mission spearheaded by the European Space Agency with support and instruments provided by NASA.

Philae's landing site, currently known as Site J, is located on the smaller of the comet's two "lobes," with a backup site on the larger lobe. The sites were selected just six weeks after Rosetta's Aug. 6 arrival at the comet, following the spacecraft's 10-year journey through the solar system.

In that time, the Rosetta mission has been conducting an unprecedented scientific analysis of the comet, a remnant from early in the solar system's 4.6-billion-year history. The latest results from Rosetta will be presented when Philae lands, during dedicated press briefings.

The main focus to date has been to survey 67P/Churyumov-Gerasimenko in order to prepare for the first-ever attempt to soft-land on a comet.

The descent to the comet is passive and it is only possible to predict that the landing point will be within a "landing ellipse" (typically a few hundred yards or meters in size). For each of Rosetta's candidate sites, a larger area -- four-tenths of a square mile (one square kilometer) -- was assessed. Site J was chosen unanimously as the primary landing site because the majority of terrain within an area that size has slopes of less than 30 degrees relative to the local vertical and because there are relatively few large boulders. The area also receives sufficient daily illumination to recharge Philae and continue surface science operations beyond the initial 64-hour battery-powered phase.

Over the last two weeks, the flight dynamics and operations teams at ESA have been making a detailed analysis of flight trajectories and timings for Rosetta to deliver the lander at the earliest possible opportunity.

Two robust landing scenarios have been identified, one for the primary site and one for the backup. Both anticipate separation and landing on Nov. 12.

For the primary landing scenario, targeting Site J, Rosetta will release Philae at 08:35 UTC (12:35 a.m. PST; 9:35 a.m. Central European Time) at a distance of 14 miles (22.5 kilometers) from the center of the comet, landing about seven hours later. The one-way signal travel time between Rosetta and Earth on Nov. 12 will be 28 minutes and 20 seconds, meaning that confirmation of the landing will arrive at Earth ground stations at around 16:00 UTC (8 a.m. PST; 5 p.m. CET).

If a decision is made to use the backup site, Site C, separation will occur at 13:04 UTC (5:04 a.m. PST; 2:04 p.m. CET) at a distance of 7.8 miles (12.5 kilometers) from the center of the comet. Landing will occur about four hours later, with confirmation on Earth at around 17:30 UTC (9:30 a.m. PST; 6:30 p.m. CET). The timings are subject to uncertainties of several minutes.

Final confirmation of the primary landing site and its landing scenario will be made on October 14 after a formal Lander Operations Readiness Review, which will include the results of additional high-resolution analysis of the landing sites conducted in the meantime. Should the backup site be chosen at this stage, landing can still occur on Nov. 12.

A competition for the public to name the primary landing site will also be announced during the week of Oct. 14.

Following the Philae landing, the Rosetta orbiter will continue to study the comet and its environment using 11 science instruments for another year as the spacecraft and comet orbit the sun together. The comet is on an elliptical 6.5-year orbit that takes it from beyond Jupiter at its farthest point, to between the orbits of Mars and Earth at its closest to the sun. Rosetta will accompany the comet for more than a year as they swing around the sun and back to the outer solar system again.

The analyses made by the Rosetta orbiter will be complemented by the measurements performed on the comet by Philae's 10 instruments.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, the Rosetta mission should become key to unlocking the history and evolution of our solar system, as well as answering questions regarding the origin of Earth's water and perhaps even life.

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by the German Aerospace Center, Cologne; Max Planck Institute for Solar System Research, Gottingen; National Center of Space Studies of France (CNES), Paris; and the Italian Space Agency, Rome. NASA's Jet Propulsion Laboratory in Pasadena, California, a division of the California Institute of Technology, manages the U.S. participation in the Rosetta mission for NASA's Science Mission Directorate in Washington.

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

DC Agle/Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011/818-354-6278
agle@jpl.nasa.gov/guy.webster@jpl.nasa.gov

2014-326

Posted by Nelio Inacio at 3:39 PM 0 comments

Cassini Watches Mysterious Feature Evolve in Titan Sea

Cassini Watches Mysterious Feature Evolve in Titan Sea: Mysterious Changing Feature in Ligeia Mare These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell
› Full image and caption


September 29, 2014

NASA's Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn's moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini's radar experiment, but its appearance changed between the two apparitions.

Images of the feature taken during the Cassini flybys are available at:

http://photojournal.jpl.nasa.gov/catalog/PIA18430

The mysterious feature, which appears bright in radar images against the dark background of the liquid sea, was first spotted during Cassini's July 2013 Titan flyby. Previous observations showed no sign of bright features in that part of Ligeia Mare. Scientists were perplexed to find the feature had vanished when they looked again, over several months, with low-resolution radar and Cassini's infrared imager. This led some team members to suggest it might have been a transient feature. But during Cassini's flyby on August 21, 2014, the feature was again visible, and its appearance had changed during the 11 months since it was last seen.

Scientists on the radar team are confident that the feature is not an artifact, or flaw, in their data, which would have been one of the simplest explanations. They also do not see evidence that its appearance results from evaporation in the sea, as the overall shoreline of Ligeia Mare has not changed noticeably.

The team has suggested the feature could be surface waves, rising bubbles, floating solids, solids suspended just below the surface, or perhaps something more exotic.

The researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon's northern hemisphere. Monitoring such changes is a major goal for Cassini's current extended mission.

"Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan," said Stephen Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, California. "We're hopeful that we'll be able to continue watching the changes unfold and gain insights about what's going on in that alien sea."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

For more information about Cassini and its mission, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov

2014-327

Posted by Nelio Inacio at 3:38 PM 0 comments

Wednesday, September 24, 2014

Prospects have been fading for an El Niño event in 2014, but now there's a glimmer of hope...

Prospects have been fading for an El Niño event in 2014, but now there's a glimmer of hope...: The image shows Kelvin waves of high sea level (red/yellow) crossing the Pacific Ocean at the equator. The image shows Kelvin waves of high sea level (red/yellow) crossing the Pacific Ocean at the equator. The waves can be related to El Niño events. Green indicates normal sea level, and blue/purple areas are lower than normal. Data are from the NASA/European Jason-2 satellite, collected Sept. 13-22, 2014. Image credit: NASA/JPL-Caltech

› Full image and caption


September 22, 2014

Prospects have been fading for an El Niño event in 2014, but now there's a glimmer of hope for a very modest comeback. Scientists warn that unless these developing weak-to-modest El Niño conditions strengthen, the drought-stricken American West shouldn't expect any relief.

The latest sea-level-height data from the NASA/European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite mission show a pair of eastward-moving waves of higher sea level, known as Kelvin waves, in the Pacific Ocean -- the third such pair of waves this year. Now crossing the central and eastern equatorial Pacific, these warm waves appear as the large area of higher-than-normal sea surface heights (warmer-than-normal ocean temperatures) hugging the equator between 120 degrees west and the International Dateline. The Kelvin waves are traveling eastward and should arrive off Ecuador in late September and early October.

A series of larger atmospheric "west wind bursts" from February through May 2014 triggered an earlier series of Kelvin waves that raised hopes of a significant El Niño event. Just as the warming of the eastern equatorial Pacific by these waves dissipated, damping expectations for an El Niño this year, these latest Kelvin waves have appeared, resuscitating hopes for a late arrival of the event.

The new image is online at:

http://www.jpl.nasa.gov/images/earth/elnino/earth20140922-full.jpg

For an overview of 2014's El Niño prospects and Kelvin waves, please see:

http://science.nasa.gov/science-news/science-at-nasa/2014/19may_elnino/

Climatologist Bill Patzert of NASA's Jet Propulsion Laboratory, Pasadena, California, says it's too early to know for sure, but he would not be surprised if the latest Kelvin waves are the "last hurrah" for this much-hoped-for El Niño. "Since February 2014, the prospect of an El Niño has waxed and waned. This late in the season, the best we can expect is a weak to moderate event. What comes next is not yet clear. But for the drought-plagued American West, the possibility of a badly needed drenching is fading," said Patzert.

NASA scientists will continue to monitor the Pacific to see what is in store next for the world's climate.

This image was created with data collected by the U.S./European OSTM/Jason-2 satellite during a 10-day period centered on Sept. 18, 2014. It shows a red and yellow area in the central and eastern equatorial Pacific, indicating that the ocean surface is about 4 to 6 inches (10 to 12 centimeters) above normal. Green indicates near-normal conditions. These regions contrast with the western equatorial Pacific, where sea levels (blue and purple areas) are 3 to 6 inches (8 to 15 centimeters) lower than normal.

The height of the ocean water relates, in part, to its temperature, and thus is an indicator of the amount of heat stored in the ocean below. As the ocean warms, the water expands and the sea level rises; as it cools, its level falls. Above-normal height variations along the equatorial Pacific indicate El Niño conditions, while below-normal height variations indicate La Niña conditions. The temperature of the upper ocean can have a significant influence on weather patterns and climate.

This latest image highlights the processes that occur on time scales of more than a year but usually less than 10 years, such as El Niño and La Niña. The image also highlights faster ocean processes such as Kelvin waves. As Patzert says, "Jason-2 is a fantastic Kelvin wave counter." These processes are known as the interannual ocean signal. To show that signal, scientists refined data for this image by removing trends over the past 21 years, seasonal variations and time-averaged signals of large-scale ocean circulation. For a more detailed explanation of what this type of image means, visit:

http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/

The comings and goings of El Niño and La Niña are part of the long-term, evolving state of global climate, for which measurements of sea surface height are a key indicator. Jason-2 is a joint effort between NASA, the National Oceanic and Atmospheric Administration (NOAA), the French Space Agency Centre National d'Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). JPL manages the U.S. portion of Jason-2 for NASA's Science Mission Directorate, Washington, D.C. In early 2015, NASA and its international partners CNES, NOAA and EUMETSAT will launch Jason-3, which will extend the timeline of ocean surface topography measurements begun by the Topex/Poseidon and Jason 1 and 2 satellites. Jason-3 will make highly detailed measurements of sea level on Earth to gain insight into ocean circulation and climate change. JPL is a division of the California Institute of Technology.

For a time sequence of the evolution of the 2014 El Nino, visit:

http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/archive/

To learn more on NASA's satellite altimetry programs, visit:

http://sealevel.jpl.nasa.gov

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, California

Alan.Buis@jpl.nasa.gov

2014-319

Posted by Nelio Inacio at 11:06 AM 0 comments

Monday, September 22, 2014

NASA's Newest Mars Mission Spacecraft Enters Orbit around Red Planet

NASA's Newest Mars Mission Spacecraft Enters Orbit around Red Planet: MAVEN (Artist's Concept) This image shows an artist concept of NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission. Image Credit: NASA/Goddard Space Flight Center

› Full image and caption


September 21, 2014

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars' orbit at 7:24 p.m. PDT (10:24 p.m. EDT) Sunday, Sept. 21, where it now will prepare to study the Red Planet's upper atmosphere as never done before. MAVEN is the first spacecraft dedicated to exploring the tenuous upper atmosphere of Mars.

"As the first orbiter dedicated to studying Mars' upper atmosphere, MAVEN will greatly improve our understanding of the history of the Martian atmosphere, how the climate has changed over time, and how that has influenced the evolution of the surface and the potential habitability of the planet," said NASA Administrator Charles Bolden. "It also will better inform a future mission to send humans to the Red Planet in the 2030s."

After a 10-month journey, confirmation of successful orbit insertion was received from MAVEN data observed at the Lockheed Martin operations center in Littleton, Colorado, as well as from tracking data monitored at NASA's Jet Propulsion Laboratory navigation facility in Pasadena, California. The telemetry and tracking data were received by NASA's Deep Space Network antenna station in Canberra, Australia.

"NASA has a long history of scientific discovery at Mars and the safe arrival of MAVEN opens another chapter," said John Grunsfeld, astronaut and associate administrator of the NASA Science Mission Directorate at the agency's Headquarters in Washington. "Maven will complement NASA's other Martian robotic explorers-and those of our partners around the globe-to answer some fundamental questions about Mars and life beyond Earth."

Following orbit insertion, MAVEN will begin a six-week commissioning phase that includes maneuvering into its final science orbit and testing the instruments and

science-mapping commands. MAVEN then will begin its one Earth-year primary mission, taking measurements of the composition, structure and escape of gases in Mars' upper atmosphere and its interaction with the sun and solar wind.

"It's taken 11 years from the original concept for MAVEN to now having a spacecraft in orbit at Mars," said Bruce Jakosky, MAVEN principal investigator with the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder (CU/LASP). "I'm delighted to be here safely and successfully, and looking forward to starting our science mission."

The primary mission includes five "deep-dip" campaigns, in which MAVEN's periapsis, or lowest orbit altitude, will be lowered from 93 miles (150 kilometers) to about 77 miles (125 kilometers). These measurements will provide information down to where the upper and lower atmospheres meet, giving scientists a full profile of the upper tier.

"This was a very big day for MAVEN," said David Mitchell, MAVEN project manager from NASA's Goddard Space Flight Center, Greenbelt, Maryland. "We're very excited to join the constellation of spacecraft in orbit at Mars and on the surface of the Red Planet. The commissioning phase will keep the operations team busy for the next six weeks, and then we'll begin, at last, the science phase of the mission. Congratulations to the team for a job well done today."

MAVEN launched Nov. 18, 2013, from Cape Canaveral Air Force Station in Florida, carrying three instrument packages. The Particles and Fields Package, built by the University of California at Berkeley with support from CU/LASP and Goddard, contains six instruments that will characterize the solar wind and the ionosphere of the planet. The Remote Sensing Package, built by CU/LASP, will identify characteristics present throughout the upper atmosphere and ionosphere. The Neutral Gas and Ion Mass Spectrometer, provided by Goddard, will measure the composition and isotopes of atomic particles.

The spacecraft's principal investigator is based at CU/LASP. The university provided two science instruments and leads science operations, as well as education and public outreach, for the mission.

NASA Goddard Space Flight Center manages the project and also provided two science instruments for the mission. Lockheed Martin built the spacecraft and is responsible for mission operations. The Space Sciences Laboratory at the University of California at Berkeley provided four science instruments for MAVEN. JPL provides navigation and Deep Space Network support, and Electra telecommunications relay hardware and operations. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Program for NASA.

To learn more about the MAVEN mission, visit:

http://www.nasa.gov/maven

and

http://mars.nasa.gov/maven/

Dwayne Brown

Headquarters, Washington

202-358-1726

dwayne.c.brown@nasa.gov

Nancy Neal-Jones / Elizabeth Zubritsky

Goddard Space Flight Center, Greenbelt, Maryland

301-286-0039 / 301-614-5438

nancy.n.jones@nasa.gov / elizabeth.a.zubritsky@nasa.gov

2014-318

Posted by Nelio Inacio at 5:43 AM 0 comments

Saturday, September 20, 2014

How a Planet Can Mess Up a Star's Looks

How a Planet Can Mess Up a Star's Looks:

Note: An earlier version of this article appeared on Peter Edmonds' blog.

Recently, beautiful photos of auroras have been in the news. These colorful light shows were generated by solar storms, and provide a vivid demonstration of activity on the Sun affecting the Earth. The pummeling experienced by our home planet is an example of our one-way relationship with the Sun: it can have a noticeable effect on the Earth, but the Earth has a negligible effect on the Sun. Further afield in the galaxy, this isn't always the case. In a few other systems planets can have a big effect on their star, changing their looks in surprising ways.



A spectacular picture of auroras by photographer Mike Taylor taken over Unity Pond in Waldo County, Maine on September 12, 2014. Credit: Mike Taylor photography.

As explained in the latest press release from NASA's Chandra X-ray Observatory, an exoplanet called WASP-18b appears to be causing the star it orbits to act much older than it actually is. WASP-18b is an example of a hot Jupiter, with a mass about ten times that of Jupiter and an orbit that is less than 24 hours long. The host star, WASP-18, is estimated to have an age that lies between about 500 million and 2 billion years, relatively young by astronomical standards.

Younger stars tend to be more active stars, with stronger magnetic fields, larger flares, and more intense X-ray emission than their older counterparts. Magnetic activity, flaring, and X-ray emission are linked to the stellar rotation, which generally declines with age. However, when astronomers took a long look with Chandra at WASP-18, they didn’t detect any X-rays. Using established relations between the magnetic activity and X-ray emission of stars and their age indicates that WASP-18 is about 100 times less active than it should be at its age.

The researchers argue that tidal forces from the gravitational pull of the massive planet – similar to those the Moon has on Earth’s tides but on a much larger scale – may have disrupted the magnetic field of the star. The strength of the magnetic field depends on the amount of convection in the star. Convection is the process where hot gas stirs the interior of the star.

The planet’s gravity may cause motions of gas in the interior of the star that weaken the convection, causing the magnetic field to weaken and activity to decline. This causes the appearance of premature aging in the star. WASP-18 is thought to have a shallow convection zone, making it unusually susceptible to tidal effects.



Shown in the main part of this graphic is an artist's impression of the star WASP-18 and, in the foreground, its hot Jupiter WASP-18b. The insets show the star in the optical image and its non-detection in X-rays with Chandra. Credit: X-ray: NASA/CXC/SAO/I.Pillitteri et al; Optical: DSS; Illustration: NASA/CXC/M.Weiss

What about other hot Jupiters that are relatively massive and close to their star? In some cases - where they orbit a different type of star to WASP-18 - the effect of hot Jupiters can be flipped and they can make a star appear younger than it really is. In the cases of HD 189733 and CoRoT-2a the presence of the planet appears to have increased the amount of activity in the star. In these cases the stars have much deeper convection zones than WASP-18 and tidal effects have little influence on convection and hence on the star's dynamo. Instead, the planets may be speeding up their star's rotation, leading to a more powerful dynamo and more activity than expected for the star's age. In these cases having a companion makes the star act younger than it really is. That makes sense for people and, in a few cases, for stars.



An artist's impression of the star CoRoT-2a and its hot Jupiter exoplanet, CoRoT-2b. Credit: NASA/CXC/M.Weiss

I've discussed the effects that extreme hot Jupiters can have on their host star. In such systems, what effect does the star have on its planet? In the cases of HD 189733 and CoRoT-2a, strong X-rays and ultraviolet radiation from the active star are evaporating the atmospheres of the planet. For HD 189733, astronomers estimate the planet is losing 100 to 600 million kilograms per second, and for CoRoT-2a astronomers estimate the planet is losing about 5 billion kilograms per second. For WASP-18, with much weaker X-ray emission and ultraviolet radiation, there is much less evaporation of the nearby planet's upper atmosphere than there would be if the star was more active. In effect, the planet is protecting itself. Its gravity causes the nearby star to be less active, and that causes the planet to be struck with less damaging radiation. HD 189733b and CoRoT-2b, on the other hand, are behaving in a self-destructive manner.

Talk of planet destruction isn’t necessary for our present-day solar system, where the planets are much further away from the Sun than hot Jupiters are. However, that won’t always be the case. A few billion years in the future, the Sun will dramatically expand in size when it becomes a red giant. Our oceans will boil away, never to return and what’s left of the Earth may end up spiraling in towards the Sun. We don't know the exact fate of our home planet, but it is clear that our aurora-viewing days are numbered.

Peter Edmonds, CXC

Posted by Nelio Inacio at 1:28 PM 0 comments
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