Showing posts with label universe photos. Show all posts
Showing posts with label universe photos. Show all posts

Monday, March 23, 2015

SILVERY MOON

SILVERY MOON:



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Date: Mar 2, 2015, 12:53 PM

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Black Hole

Black Hole:



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Date: Mar 17, 2012, 9:18 PM

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As It Turns Out, We Really Are All Starstuff

As It Turns Out, We Really Are All Starstuff:



Hubble image of the Crab Nebula supernova remnant captured with the Wide Field and Planetary Camera 2. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)


Hubble image of the Crab Nebula supernova remnant captured with the Wide Field and Planetary Camera 2. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)
“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars,” Carl Sagan famously said in his 1980 series Cosmos. “We are made of starstuff.”

And even today, observations with NASA’s airborne SOFIA observatory are supporting this statement. Measurements taken of the dusty leftovers from an ancient supernova located near the center our galaxy – aka SNR Sagittarius A East – show enough “starstuff” to build our entire planet many thousands of times over.

“Our observations reveal a particular cloud produced by a supernova explosion 10,000 years ago contains enough dust to make 7,000 Earths,” said research leader Ryan Lau of Cornell University in Ithaca, New York – the same school, by the way, where Carl Sagan taught astronomy and space science.



Composite image of SNR Sgr A East showing infrared SOFIA data outlined in white against X-ray and radio observations. (NASA/CXO/Herschel/VLA/Lau et al.)


Composite image of SNR Sgr A East showing infrared SOFIA data outlined in white against X-ray and radio observations. (NASA/CXO/Herschel/VLA/Lau et al.)
While it’s long been known that supernovae expel enormous amounts of stellar material into space, it wasn’t understood if clouds of large-scale dust could withstand the immense shockwave forces of the explosion.



NASA's Stratospheric Observatory for Infrared Astronomy 747SP aircraft flies over Southern California's high desert during a test flight in 2010. Credit: NASA/Jim Ross


NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft (Credit: NASA/Jim Ross)
These observations, made with the joint NASA/DLR-developed Faint Object InfraRed Camera for the SOFIA Telescope (FORCAST) instrument, provide key “missing-link” evidence that dust clouds do in fact survive intact, spreading outward into interstellar space to seed the formation of new systems.

Interstellar dust plays a vital role in the evolution of galaxies and the formation of new stars and protoplanetary discs – the orbiting “pancakes” of material around stars from which planets (and eventually everything on them) form.

The findings may also answer the question of why young galaxies observed in the distant universe possess so much dust; it’s likely the result of frequent supernova explosions from massive early-generation stars.

Read more in a NASA news release here.

Source: NASA, Cornell, and Caltech 

“We have begun to contemplate our origins: starstuff pondering the stars; organized assemblages of ten billion billion billion atoms considering the evolution of atoms; tracing the long journey by which, here at least, consciousness arose.”

– Carl Sagan, Cosmos (1980)


About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!

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Northern Equinox Eclipse

Northern Equinox Eclipse: APOD: 2015 March 21 - Northern Equinox Eclipse


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2015 March 21


See Explanation. Clicking on the picture will download the highest resolution version available.
Explanation: Snowy and cold is weather you might expect at the start of spring for Longyearbyen on the Arctic archipelago of Svalbard, Norway. But that turned out to be good weather for watching the Moon's umbral shadow race across northern planet Earth. The region was plunged into darkness for 3 minutes during the March 20 total solar eclipse while insulated eclipse chasers witnessed the dark Sun in the cold clear sky. In this well-timed snapshot captured near the end of totality, the Moon's shadow sweeps away from the horizon and the solar corona fades as the lunar disk just begins to uncover the Sun. Streaming past the Moon's edge, direct rays of sunlight create the fleeting appearance of a glistening diamond ring.

A Double Eclipse of the Sun

A Double Eclipse of the Sun: APOD: 2015 March 22 - A Double Eclipse of the Sun


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2015 March 22



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Explanation: Can the Sun be eclipsed twice at the same time? Last Friday was noteworthy because part of the Earth was treated to a rare total eclipse of the Sun. But also on Friday, from a part of the Earth that only saw part of the Sun eclipsed, a second object appeared simultaneously in front of the Sun: the Earth-orbiting International Space Station. Although space station eclipses are very quick -- in this case only 0.6 seconds, they are not so rare. Capturing this composite image took a lot of planning and a little luck, as the photographer had to dodge a series of third objects that kept, annoyingly, also lining up in front of the Sun: clouds. The above superposed time-lapse sequence was taken from Fregenal de la Sierra in southern Spain. The dark disk of the Moon dominates the lower right, while the Sun's textured surface shows several filaments and, over an edge, a prominence.

Saturday, March 21, 2015

A Colorful Moon

A Colorful Moon: APOD: 2013 December 19 - A Colorful Moon


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2013 December 19


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Explanation: The Moon is normally seen in subtle shades of grey or yellow. But small, measurable color differences have been greatly exaggerated to make this telescopic, multicolored, moonscape captured during the Moon's full phase. The different colors are recognized to correspond to real differences in the chemical makeup of the lunar surface. Blue hues reveal titanium rich areas while orange and purple colors show regions relatively poor in titanium and iron. The familiar Sea of Tranquility, or Mare Tranquillitatis, is the blue area in the upper right corner of the frame. White lines radiate across the orange-hued southern lunar highlands from 85 kilometer wide ray crater Tycho at bottom left. Above it, darker rays from crater Copernicus extend into the Sea of Rains (Mare Imbrium) at the upper left. Calibrated by rock samples from the Apollo missions, similar multicolor images from spacecraft have been used to explore the Moon's global surface composition.

Titan's Land of Lakes

Titan's Land of Lakes: APOD: 2013 December 20 - Titan's Land of Lakes


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2013 December 20


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Explanation: Saturn's large moon Titan would be unique in our solar system, the only world with stable liquid lakes and seas on its surface ... except for planet Earth of course. Centered on the north pole, this colorized map shows Titan's bodies of methane and ethane in blue and black, still liquid at frigid surface temperatures of -180 degrees C (-292 degrees F). The map is based on data from the Cassini spacecraft's radar, taken during flybys between 2004 and 2013. Roughly heart-shaped, the lake above and right of the pole is Ligeia Mare, the second largest known body of liquid on Titan and larger than Lake Superior on Earth. Just below the north pole is Punga Mare. The sprawling sea below and right of Punga is the (hopefully sleeping) Kraken Mare, Titan's largest known sea. Above and left of the pole, the moon's surface is dotted with smaller lakes that range up to 50 kilometers across.

SDO's Multiwavelength Sun

SDO's Multiwavelength Sun: APOD: 2013 December 21 - SDO's Multiwavelength Sun


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2013 December 21
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Explanation: Today, the solstice is at 17:11 Universal Time, the Sun reaching the southernmost declination in its yearly journey through planet Earth's sky. The December solstice marks the astronomical beginning of winter in the northern hemisphere and summer in the south. To celebrate, explore this creative visualization of the Sun from visible to extreme ultraviolet wavelengths, using image data from the orbiting Solar Dynamics Observatory (SDO). Against a base image made at a visible wavelengths, the wedge-shaped segments show the solar disk at increasingly shorter ultraviolet and extreme ultraviolet wavelengths. Shown in false-color and rotating in a clockwise direction, the filters decrease in wavelength from 170 nanometers (in pink) through 9.4 nanometers (green). At shorter wavelengths, the altitude and temperature of the regions revealed in the solar atmosphere tend to increase. Bright at visible wavelengths, the solar photosphere looks darker in the ultraviolet, but sunspots glow and bright plasma traces looping magnetic fields. Watch the filters sweep around the solar disk in this animation of SDO's multiwavelength view of the Sun.

Tutulemma: Solar Eclipse Analemma

Tutulemma: Solar Eclipse Analemma: APOD: 2013 December 22 - Tutulemma: Solar Eclipse Analemma


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2013 December 22


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Tutulemma: Solar Eclipse Analemma

Image Credit & Copyright: Cenk E. Tezel and Tunç Tezel (TWAN)
Explanation: If you went outside at exactly the same time every day and took a picture that included the Sun, how would the Sun's position change? With great planning and effort, such a series of images can be taken. The figure-8 path the Sun follows over the course of a year is called an analemma. Yesterday, the Winter Solstice day in Earth's northern hemisphere, the Sun appeared at the bottom of the analemma. Analemmas created from different latitudes would appear at least slightly different, as well as analemmas created at a different time each day. With even greater planning and effort, the series can include a total eclipse of the Sun as one of the images. Pictured is such a total solar eclipse analemma or Tutulemma - a term coined by the photographers based on the Turkish word for eclipse. The above composite image sequence was recorded from Turkey starting in 2005. The base image for the sequence is from the total phase of a solar eclipse as viewed from Side, Turkey on 2006 March 29. Venus was also visible during totality, toward the lower right.

Geminid Meteors over Chile

Geminid Meteors over Chile: APOD: 2013 December 23 - Geminid Meteors over Chile


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2013 December 23


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Explanation: From a radiant point in the constellation of the Twins, the annual Geminid meteor shower rained down on planet Earth over the past few weeks. Recorded near the shower's peak over the night of December 13 and 14, the above skyscape captures Gemini's shooting stars in a four-hour composite from the dark skies of the Las Campanas Observatory in Chile. In the foreground the 2.5-meter du Pont Telescope is visible as well as the 1-meter SWOPE telescope. The skies beyond the meteors are highlighted by Jupiter, seen as the bright spot near the image center, the central band of our Milky Way Galaxy, seen vertically on the image left, and the pinkish Orion Nebula on the far left. Dust swept up from the orbit of active asteroid 3200 Phaethon, Gemini's meteors enter the atmosphere traveling at about 22 kilometers per second.

Sharpless 308: Star Bubble

Sharpless 308: Star Bubble: APOD: 2013 December 24 - Sharpless 308: Star Bubble


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2013 December 24


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Sharpless 308: Star Bubble

Image Credit & Copyright: Jeff Husted
Explanation: Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured in the expansive image is dominated by the glow of ionized oxygen atoms mapped to violet hues.

Melotte 15 in the Heart

Melotte 15 in the Heart: APOD: 2013 December 27 - Melotte 15 in the Heart


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2013 December 27


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Explanation: Cosmic clouds seem to form fantastic shapes in the central regions of emission nebula IC 1805. Of course, the clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are near the center of this colorful skyscape, along with dark dust clouds in silhouette. Dominated by emission from atomic hydrogen, the telescopic view spans about 30 light-years. But wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - The Heart Nebula. IC 1805 is located along the northern Milky Way, about 7,500 light years distant toward the constellation Cassiopeia.

Alaska Aurora Sequence

Alaska Aurora Sequence: APOD: 2013 December 28 - Alaska Aurora Sequence


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2013 December 28


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Explanation: A remarkably intense auroral band flooded the northern night with shimmering colors on December 7. The stunning sequence captured here was made with a camera fixed to a tripod under cold, clear skies near Ester, just outside of Fairbanks, Alaska. Left to right, spanning a period of about 30 minutes, the panels follow changes in the dancing curtains of northern lights extending to altitudes of over 100 kilometers in a band arcing directly overhead. The panels span 150 degrees vertically, covering about 500 kilometers of aurora laying across the sky from edge to edge. The auroral activity was triggered by a moderate level geomagnetic storm, as a high speed solar wind stream buffeted planet Earth's magnetosphere.

The Horsehead Nebula

The Horsehead Nebula:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2013 December 31


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Explanation: The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula in the center of the above photograph. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will alter its appearance. The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms. Also visible at the bottom left of the picture is a greenish reflection nebulae that preferentially reflects the blue light from nearby stars.

A New Year's Crescent

A New Year's Crescent: APOD: 2014 January 1 - A New Year's Crescent


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 January 1


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Explanation: That's not the young crescent Moon poised above the western horizon at sunset. Instead it's Venus in a crescent phase, captured with a long telephoto lens from Quebec City, Canada, planet Earth on a chilly December 30th evening. The very bright celestial beacon is dropping lower into the evening twilight every day. But it also grows larger in apparent size and becomes a steadily thinner crescent in binocular views as it heads toward an inferior conjunction, positioned between the Earth and the Sun on January 11. The next few evenings will see a young crescent Moon join the crescent Venus in the western twilight, though. Historically, the first observations of the phases of Venus were made by Galileo with his telescope in 1610, evidence consistent with the Copernican model of the Solar System, but not the Ptolemaic system.

Lovejoy in the New Year

Lovejoy in the New Year: APOD: 2014 January 3 - Lovejoy in the New Year


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 January 3


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Explanation: A rival to vanquished Comet ISON in 2013, Comet Lovejoy (C/2013 R1) still sweeps through early morning skies, captured in this starry scene on New Year's day. The frame stretches some 3.5 degrees (about 7 full moons) across a background of faint stars in the constellation Hercules. Only just visible to the naked eye from dark sites before dawn, Lovejoy remains a good target for the northern hemisphere's binocular equipped skygazers. But this deep exposure shows off Lovejoy's beautiful tails and tantalizing greenish coma better than binocular views. Not a sungrazer, this Comet Lovejoy made its closest approach to the Sun around December 22, looping high above the ecliptic plane. Now headed for the outer Solar System, Lovejoy began the new year about 6.7 light-minutes from planet Earth.

Clouds and Crescents

Clouds and Crescents: APOD: 2014 January 4 - Clouds and Crescents


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 January 4


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Explanation: A crescent Venus shines along the western horizon at dusk in this clearing sky. The Earth's sister planet is smiling between the low clouds near the bottom of the frame during its January 2nd conjunction with the slender, young crescent Moon above. Of course the lovely pairing of Moon and Venus crescents could be enjoyed in the new year's skies around the the world. But the twin contrails in this scene belong to an aircraft above Appenzell, Switzerland. Soon to disappear from evening skies, Venus is heading toward its January 11th inferior conjunction and an appearance in predawn skies as planet Earth's morning star by late January. And the Moon will be young again, too.

Galaxy NGC 474: Shells and Star Streams

Galaxy NGC 474: Shells and Star Streams: APOD: 2014 January 5 - Galaxy NGC 474: Shells and Star Streams


Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 January 5


See Explanation. Clicking on the picture will download the highest resolution version available.
Explanation: What's happening to galaxy NGC 474? The multiple layers of emission appear strangely complex and unexpected given the relatively featureless appearance of the elliptical galaxy in less deep images. The cause of the shells is currently unknown, but possibly tidal tails related to debris left over from absorbing numerous small galaxies in the past billion years. Alternatively the shells may be like ripples in a pond, where the ongoing collision with the spiral galaxy just above NGC 474 is causing density waves to ripple though the galactic giant. Regardless of the actual cause, the above image dramatically highlights the increasing consensus that at least some elliptical galaxies have formed in the recent past, and that the outer halos of most large galaxies are not really smooth but have complexities induced by frequent interactions with -- and accretions of -- smaller nearby galaxies. The halo of our own Milky Way Galaxy is one example of such unexpected complexity. NGC 474 spans about 250,000 light years and lies about 100 million light years distant toward the constellation of the Fish (Pisces).

M7: Open Star Cluster in Scorpius

M7: Open Star Cluster in Scorpius: APOD: 2014 January 7 - M7: Open Star Cluster in Scorpius


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2014 January 7



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M7: Open Star Cluster in Scorpius

Image Credit & Copyright: Lorand Fenyes
Explanation: M7 is one of the most prominent open clusters of stars on the sky. The cluster, dominated by bright blue stars, can be seen with the naked eye in a dark sky in the tail of the constellation of the Scorpion (Scorpius). M7 contains about 100 stars in total, is about 200 million years old, spans 25 light-years across, and lies about 1000 light-years away. The above deep image, taken last June from Hungary through a small telescope, combines over 60 two-minute exposures. The M7 star cluster has been known since ancient times, being noted by Ptolemy in the year 130 AD. Also visible are a dark dust cloud and literally millions of unrelated stars towards the Galactic center.

Nova in Sagittarius Brighter Than Ever – Catch it with the Naked Eye!

Nova in Sagittarius Brighter Than Ever – Catch it with the Naked Eye!:



Nova Sagittarii 2015 No. 2 photographed this morning when it was easily visible to the naked eye at magnitude +4.4. The nova has been on the upswing since its discovered less than a week ago. Credit: Bob King


Nova Sagittarii 2015 No. 2 in the Sagittarius “Teapot”was easily visible with the naked eye at magnitude +4.4 when this photo was taken today March 21. The nova has been steadily brightening since its discovery less than a week ago. Credit: Bob King
Great news about that new nova in Sagittarius. It’s still climbing in brightness and now ranks as the brightest nova seen from mid-northern latitudes in nearly two years. Even from the northern states, where Sagittarius hangs low in the sky before dawn, the “new star” was easy to spy this morning at magnitude +4.4.

While not as rare as hen’s teeth, novae aren’t common and those visible without optical aid even less so. The last naked eye nova seen from outside the tropics was V339 Del (Nova Delphini), which peaked at +4.3 in August 2013. The new kid on the block could soon outshine it if this happy trend continues.



This view shows the sky facing south-southeast just before the start of dawn in mid-March from the central U.S. The nova's located squarely in the Teapot constellation. Source: Stellarium


This view shows the sky facing south-southeast shortly before the start of dawn in late March from the central U.S. The nova is centrally located within the Teapot. Source: Stellarium
Now bearing the official title of Nova Sagittarii 2015 No. 2, the nova was discovered on March 15 by amateur astronomer and nova hunter John Seach of Chatsworth Island, NSW, Australia. At the time it glowed at the naked eye limit of magnitude +6. Until this morning I wasn’t able to see it with the naked eye, but from a dark sky site, it’s there for the picking. So long as you know exactly where to look.

The chart and photo above will help guide you there. At the moment, the star’s about 15° high at dawn’s start, but it rises a little higher and becomes easier to see with each passing day. Find your sunrise time HERE and then subtract an hour and 45 minutes. That will bring you to the beginning of astronomical twilight, an ideal time to catch the nova at its highest in a dark sky.



Use this AAVSO chart to pinpoint the nova's location and also to help you estimate its brightness. Numbers shown are star magnitudes with the decimal points omitted. Credit: AAVSO


Use this AAVSO chart to pinpoint the nova’s location and also to help you estimate its brightness. Numbers shown are star magnitudes with the decimal points omitted. Credit: AAVSO
To see it with the naked eye, identify the star with binoculars first and then aim your gaze there. I hope you’ll be as pleasantly surprised as I was to see it. To check on the nova’s ups and downs, drop by the American Association Variable Star Observers (AAVSO) list of recent observations.

Seeing the nova without optical aid took me back to the time before the telescope when a “new star” in the sky would have been met with great concern. Changes in the heavens in that pre-telescopic era were generally considered bad omens. They were also thought to occur either in Earth’s atmosphere or within the Solar System. The universe has grown by countless light years since then. Nowadays we sweat the small stuff – unseen asteroids – which were unknown in that time.



AAVSO light curve showing the nova's brightening trend since discovery. Dates are at bottom, magnitudes at left. Credit: AAVSO


AAVSO light curve showing the nova’s brightening since discovery. Dates are along the bottom, magnitudes at left. If the trend continues, Nova Sgr #2 could outshine the 2013 nova in Delphinus very soon. Credit: AAVSO
Novae occur in binary star systems where a tiny but gravitationally powerful white dwarf star pulls gases from a close companion star. The material piles up in a thin layer on the dwarf’s hot surface, fuses and burns explosively to create the explosion we dub a nova. Spectra of the expanding debris envelope reveal the imprint of hydrogen gas and as well as ionized iron.



Nova illustration with an expanding cloud of debris surrounding central fireball emitting red hydrogen-alpha light.


Artist’s view of a nova with an expanding cloud of debris surrounding  the central fireball emitting red hydrogen-alpha light.
Shortly after discovery, the nova’s debris shell was expanding at the rate of ~1,740 miles per second (2,800 km/sec) or more than 6.2 million mph (10 million mph). It’s since slowed to about half that rate. Through a telescope the star glows pale yellow but watch for its color to deepen to yellow orange and even red. Right now, it’s still in the fireball phase, with the dwarf star hidden by an envelope of fiery hydrogen gas.

As novae evolve, they’ll often turn from white or yellow to red. Emission of deep red light from hydrogen atoms – called hydrogen alpha –  gives them their warm, red color. Hydrogen, the most common element in stars, gets excited through intense radiation or collisions with atoms (heat) and re-emits a ruby red light when it returns to its rest state. Astronomers see the light as bright red emission line in the star’s spectrum. Spectra of the nova show additional emission lines of hydrogen beta or H-beta (blue light emitted by hydrogen) and iron.

There are actually several reasons why novae rouge up over time, according to former AAVSO director Arne Henden:

“Energy from the explosion gets absorbed by the surrounding material in a nova and re-emitted as H-alpha,” said Henden. Not only that but as the explosion expands over time, the same amount of energy is spread over a larger area.

“The temperature drops,” said Henden, “causing the fireball to cool and turn redder on its own.” As the eruption expands and cools, materials blasted into the surrounding space condense into a shell of soot that absorbs that reddens the nova much the same way dusty air reddens the Sun.

Nova Sagittarii’s current pale yellow color results from seeing a mix of light –  blue from the explosion itself plus red from the expanding fireball. As for its distance from Earth, I haven’t heard, but given that the progenitor star was 15th magnitude or possibly fainter, we’re probably talking in the thousands of light years.



Wide view of the Sagittarius-Scorpius region with some of the brighter star clusters and nebulae labeled for binocular browsing. Credit: Bob King


Wide view of the Sagittarius-Scorpius region with some of the brighter star clusters and nebulae labeled for binocular browsing. Credit: Bob King
In an earlier article on the nova’s discovery I mentioned taking a look at Saturn as long as you made the effort the get up early. Here’s a photo of the Sagittarius region you can use to help you further your dawn binocular explorations. The entire region is rich with star clusters and nebula, many of which were cataloged long ago by French astronomer Charles Messier, hence the “M” numbers.



About 

I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My observing passions include everything from auroras to Z Cam stars. Every day the universe offers up something both beautiful and thought-provoking. I also write a daily astronomy blog called Astro Bob.

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