Posted on by Bob King

New Binocular Nova Discovered in Sagittarius

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

Looks like the Sagittarius Teapot’s got a new whistle. On March 15, John Seach of Chatsworth Island, NSW, Australia discovered a probable nova in the heart of the constellation using a DSLR camera and fast 50mm lens. Checks revealed no bright asteroid or variable star at the location. At the time, the new object glowed at the naked eye limit of magnitude +6, but a more recent observation by Japanese amateur Koichi Itagaki puts the star at magnitude +5.3, indicating it’s still on the rise. 

A 5th magnitude nova’s not too difficult to spot with the naked eye from a dark sky, and binoculars will show it with ease. Make a morning of it by setting up your telescope for a look at Saturn and the nearby double star Graffias (Beta Scorpii), one of the prettiest, low-power doubles in the summer sky.

Close-in map of Sagittarius showing the nova's location (R.A. 18h36m57s Decl. -28°55'42") and neighboring stars with their magnitudes. For clarity, the decimal points are omitted from the magnitudes, which are from the Tycho catalog. Source: Stellarium
Close-in map of Sagittarius showing the nova’s location (R.A. 18h36m57s Decl. -28°55’42”) and neighboring stars with their magnitudes. For clarity, the decimal points are omitted from the magnitudes, which are from the Tycho catalog. Source: Stellarium

Nova means “new”, but novae aren’t fresh stars coming to life but an explosion occurring on the surface of an otherwise faint star no one’s taken notice of – until the blast causes it to brighten 50,000 to 100,000 times. A nova occurs in a close binary star system, where a small but extremely dense and massive (for its size) white dwarf siphons hydrogen gas from its closely orbiting companion. After swirling about in a disk around the dwarf, it’s funneled down to the star’s 150,000 F° surface where gravity compacts and heats the gas until detonates in a titanic thermonuclear explosion. Suddenly, a faint star that wasn’t on anyone’s radar vaults a dozen magnitudes to become a standout “new star”.

Novae occur in close binary systems where one star is a tiny but extremely compact white dwarf star. The dwarf pulls material into a disk around itself, some of which is funneled to the surface and ignites in a nova explosion. Credit: NASA
Novae occur in close binary systems where one star is a tiny but extremely compact white dwarf star. The dwarf pulls material into a disk around itself, some of which is funneled to the surface and ignites in a nova explosion. Credit: NASA

Regular nova observers may wonder why so many novae are discovered in the Sagittarius-Scorpius Milky Way region. There are so many more stars in the dense star clouds of the Milky Way, compared to say the Big Dipper or Canis Minor, that the odds go up of seeing a relatively rare event like a stellar explosion is likely to happen there than where the stars are scattered thinly. Given this galactic facts of life, that means most of will have to set our alarms to spot this nova. Sagittarius doesn’t rise high enough for a good view until the start of morning twilight. For the central U.S., that’s around 5:45-6 a.m.

A now-you-see-it-now-you-don't animation showing the nova field before and after discovery. Credit: Ernesto Guido and Nick Howes
A now-you-see-it-now-you-don’t animation showing the nova field before and after discovery. Credit: Ernesto Guido and Nick Howes

Find a location with a clear view to the southeast and get oriented at the start of morning twilight or about 100 minutes before sunrise. Using the maps, locate Sagittarius below and to the east (left) of Scorpius. Once you’ve arrived, point your binoculars into the Teapot and star-hop to the nova’s location. I’ve included visual magnitudes of neighboring stars to help you estimate the nova’s brightness and track its changes in the coming days and weeks.

Whether it continues to brighten or soon begins to fade is anyone’s guess at this point. That only makes going out and seeing it yourself that much more enticing.

New photo of Nova Sagittarii. Note the pink color from hydrogen alpha emission. Credit: Erneso Guido and Nick Howes
New photo of Nova Sagittarii. Note the “warm” color from hydrogen alpha emission. Credit: Erneso Guido and Nick Howes

UPDATE: A spectrum of the object was obtained with the Liverpool Telescope March 16 confirming that the “new star” is indeed a nova. Gas has been clocked moving away from the system at more than 6.2 million mph (10 million kph)!

Posted on by Fraser Cain

How Many Stars Did It Take To Make Us?

How Many Stars Did It Take To Make Us?

You know the quote, we’re made of stardust. Generation after generation of stars created the materials that make us up. How? And how many stars did it take?

Carl Sagan once said, “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. We are made of star stuff.” To an average person, this might sound completely bananas. I feel it could easily be adopted into the same dirty realm as “My grandpappy wasn’t no gorilla”.

After all, if my teeth are made of stars, and my toothpaste supplier can be believed, why aren’t they brighter and whiter? If my bones are made of stars, shouldn’t I have this creepy inner glow like the aliens from Cocoon? Does this mean everything I eat is made of stars? And conversely, the waste products of my body then are also made of stars? Shouldn’t all this star business include some cool interstellar powers, like Nova? Also, shouldn’t my face be burning?

When the Big Bang happened, 13.8 billion years ago, the entire Universe was briefly the temperature and pressure of a star. And in this stellar furnace, atoms of hydrogen were fused together to make helium and heavier elements like lithium and a little bit of beryllium.

This all happened between 100 and 300 seconds after the Big Bang, and then the Universe wasn’t star-like enough for fusion to happen any more. It’s like someone set a microwave timer and cooked the heck of the whole business for 5 minutes. DING! Your Universe is done! All the other elements in the Universe, including the carbon in our bodies to the gold in our jewelry were manufactured inside of stars.

But how many stars did it take to make “us”? Main sequence stars, like our own Sun, create elements slowly, but surely within their cores. As we speak, the Sun is relentlessly churning hydrogen into helium. Once when it runs out of hydrogen, it’ll switch to crushing helium into carbon and oxygen. More massive stars keep going up the periodic table, making neon and magnesium, oxygen and silicon. But those elements aren’t in you. Once a regular star gets going, it’ll hang onto its elements forever with its intense gravity. Even after it dies and becomes a white dwarf.

White Dwarf Star
White Dwarf Star

No, something needs to happen to get those elements out. That star needs to explode. The most massive stars, ones with dozens of times the mass of our Sun don’t know when to stop. They just keep on churning more and more massive elements, right on up the periodic table. They keep fusing and fusing until they reach iron in their cores. And as iron is the stellar equivalent of ash, fusion reactions no longer generate energy, and instead require energy. Without the fusion energy pushing against the force of gravity pulling everything inward, the massive star collapses in on itself, creating a neutron star or black hole, or detonating as a supernova.

It’s in this moment, a fraction of a second, when all the heavier elements are created. The gold, platinum, uranium and other rare elements that we find on Earth. All of them were created in supernovae in the past. The materials of everything around you was either created during the Big Bang or during a supernova detonation. Only supernovae “explode” and spread their material into the surrounding nebula. Our Solar System formed within a nebula of hydrogen that was enriched by multiple supernovae. Everything around you was pretty much made in a supernova.

These images taken by the Spitzer Space Telescope show the dust and gas concentrations around a supernova. Credit: NASA/JPL-Caltech
These images taken by the Spitzer Space Telescope show the dust and gas concentrations around a supernova. Credit: NASA/JPL-Caltech

So how many? How many times has this cycle been repeated? We don’t know. Lots. There were the original stars that formed shortly after the Big Bang, and then successive generations of massive stars that formed in various nebulae. Astronomers are pretty sure it was a least 3 generations of supernovae, but there’s no way to know exactly.

Carl Sagan said you’re made of star-stuff. But actually you’re made up mostly of Big Bang stuff and generations of supernova stuff. Tasty tasty supernova stuff.

What’s your favorite supernova remnant? Tell us in the comments below.

Posted on by Tammy Plotner

Radio Telescopes Help Astronomers Tune In To Nova Generated Gamma Rays

When the nova stops blowing a wind, and the material drifts off into space, the fireworks are finished. Credit: Bill Saxton, NRAO/AUI/NSF

Over two years ago, the Fermi-LAT Collaboration observed an “ear and eye opening” event – the exact location where a stellar explosion called a nova emitted one of the most energentic forms of electromagnetic waves… gamma rays. When it was first detected in 2012, it was something of a mystery, but the findings could very well point to what may cause gamma ray emissions.

“We not only found where the gamma rays came from, but also got a look at a previously-unseen scenario that may be common in other nova explosions,” said Laura Chomiuk, of Michigan State University.

A nova? According to the Fermi researchers, a classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. As it gathers in material, the thermonuclear event expels debris into surrounding space. However, astronomers didn’t expect this “normal” event to produce high energy gamma rays!

Explains the Fermi-LAT team: “The gamma-ray detections point to unexpected high-energy particle acceleration processes linked to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic gamma-ray sources.”

While NASA’s Fermi spacecraft was busy watching a nova called V959 Mon, some 6500 light-years from Earth, other radio telescopes were also busy picking up on the gamma ray incidences. The Karl G. Jansky Very Large Array (VLA) was documenting radio waves coming from the nova. The source of these emissions could be subatomic particles moving at nearly the speed of light interacting with magnetic fields – a condition needed to help produce gamma rays. These findings were backed up by the extremely-sharp radio “vision” of the Very Long Baseline Array (VLBA) and the European VLBI network. They revealed two knots in the radio observations – knots which were moving away from each other. Additional studies were done with e-MERLIN in the UK, and another round of VLA observations in 2014. Now astronomers could begin to piece together the puzzle of how radio knots and gamma rays are produced.

According to the NRAO news release, the white dwarf and its companion give up some of their orbital energy to boost some of the explosion material, making the ejected material move outward faster in the plane of their orbit. Later, the white dwarf blows off a faster wind of particles moving mostly outward along the poles of the orbital plane. When the faster-moving polar flow hits the slower-moving material, the shock accelerates particles to the speeds needed to produce the gamma rays, and the knots of radio emission.

“By watching this system over time and seeing how the pattern of radio emission changed, then tracing the movements of the knots, we saw the exact behavior expected from this scenario,” Chomiuk said.

A nova does not explode like an expanding ball, but instead throws out gas in different directions at different times and different speeds. When this gas inevitably crashes together, it produces shocks and high-energy gamma-ray photons. The complex explosion and gas collisions in nova V959 Mon is illustrated here. In the first days of the nova explosion, dense, relatively slow-moving material is expelled along the binary star system's equator (yellow material in left panel). Over the next several weeks, fast winds pick up and are blown off the binary, but they are funneled along the binary star system's poles (blue material in central panel). The equatorial and polar material crashes together at their intersection, producing shocks and gamma-ray emission (red regions in central panel). Finally, at later times, the nova stops blowing a wind, and the material drifts off into space, the fireworks finished (right panel). CREDIT: Bill Saxton, NRAO/AUI/NSF
A nova does not explode like an expanding ball, but instead throws out gas in different directions at different times and different speeds. When this gas inevitably crashes together, it produces shocks and high-energy gamma-ray photons. The complex explosion and gas collisions in nova V959 Mon is illustrated here. In the first days of the nova explosion, dense, relatively slow-moving material is expelled along the binary star system’s equator (yellow material in left panel). Over the next several weeks, fast winds pick up and are blown off the binary, but they are funneled along the binary star system’s poles (blue material in central panel). The equatorial and polar material crashes together at their intersection, producing shocks and gamma-ray emission (red regions in central panel). Finally, at later times, the nova stops blowing a wind, and the material drifts off into space, the fireworks finished (right panel). CREDIT: Bill Saxton, NRAO/AUI/NSF

But the V959 Mon observations weren’t the end of the story. According to Fermi-LAT records, in 2012 and 2013, three novae were detected in gamma rays and stood in contrast to the first gamma-ray detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft spectrum transient gamma-ray sources detected over 2-3 week durations.

“This mechanism may be common to such systems. The reason the gamma rays were first seen in V959 Mon is because it’s close,” Chomiuk said. Because the type of ejection seen in V959 Mon also is seen in other binary-star systems, the new insights may help astronomers understand how those systems develop. This “common envelope” phase occurs in all close binary stars, and is poorly understood. “We may be able to use novae as a ‘testbed’ for improving our understanding of this critical stage of binary evolution,” explains Chomiuk.

Original Story Source: Radio Telescopes Unravel Mystery of Nova Gamma Rays from National Radio Astronomy Observatory. Chomiuk worked with an international team of astronomers. The researchers reported their findings in the scientific journal “Nature”.

Posted on by Bob King

Possible Nova Pops in Cygnus

Cygnus. Credit: Stellarium

A newly-discovered star of magnitude +10.9 has flared to life in the constellation Cygnus the Swan. Koichi Nishiyama and Fujio Kabashima, both of Japan, made their discovery yesterday March 31 with a 105mm f/4 camera lens and electronic camera. They quickly confirmed the observation with additional photos taken with a 0.40-m (16-inch) reflector. Nothing was seen down to magnitude +13.4  in photos taken the on the 27th, but when they checked through images made on March 30 the star present at +12.4. Good news – it’s getting brighter!

This more detailed map, showing stars to mag. 10.5, will help you pinpoint the star. Stellarium
This more detailed map, showing stars to mag. 10.5, will help you pinpoint the star. Its coordinates are R.A. 20h 21m 42, declination +31 o3′. Stellarium

While the possible nova will need confirmation, nova lovers may want to begin observing the star as soon as possible. Novae can brighten quickly, sometimes by several magnitudes in just a day. These maps should help you hone in on the star which rises around midnight and becomes well placed for viewing around 1:30-2 a.m. local time in the eastern sky. At the moment, it will require a 4-inch or larger telescope to see, but I’m crossing my fingers we’ll see it brighten further.

Novae occur in close binary systems where one star is a tiny but extremely compact white dwarf star. The dwarf pulls material into a disk around itself, some of which is funneled to the surface and ignites in a nova explosion. Credit: NASA
Novae occur in close binary systems where one star is a tiny but extremely compact white dwarf star. The dwarf pulls material into a disk around itself, some of which is funneled to the surface and ignites in a nova explosion. Credit: NASA

To see a nova is to witness a cataclysm. Astronomers – mostly amateurs – discover about 10 a year in our Milky Way galaxy. Many more would be seen were it not for dust clouds and distance. All involve close binary stars where a tiny but extremely dense white dwarf star steals gas from its companion. The gas ultimately funnels down to the 150,000 degree surface of the dwarf where it’s compacted by gravity and heated to high temperature until it ignites in an explosive fireball. If you’ve ever wondered what a million nuclear warheads would look like detonated all at once, cast your gaze at a nova.

Novae can rise in brightness from 7 to 16 magnitudes, the equivalent of 50,000 to 100,000 times brighter than the sun, in just a few days. Meanwhile the gas they expel in the blast travels away from the binary at up to 2,000 miles per second.

One of the key diagnostics for nova identification is the appearance of deep red light in its spectrum called hydrogen alpha or H-alpha. Italian astronomer obtained this spectrum of the possible nova on April 1. Credit: Gianluca Masi
Emission of deep red light called hydrogen alpha or H-alpha is often diagnostic of a nova. When in the fireball phase, the star is hidden by a fiery cloud of rosy hydrogen gas and expanding debris cloud. Italian astronomer obtained this spectrum of the possible nova on April 1 showing H-alpha emission. Credit: Gianluca Masi

Nishiyama and Kabashima are on something of a hot streak. If confirmed, this would be their third nova discovery in a month! On March 8, they discovered Nova Cephei 2014 at magnitude 11.7 (it’s currently around 12th magnitude) and 10th magnitude Nova Scorpii 2014 (now at around 12.5) on March 26. Impressive.

Photo showing the possible nova in Cygnus. The star is described as being tinted red. Credit: Gianluca Masi
Photo showing the possible nova in Cygnus. The star is described as being tinted red. Credit: Gianluca Masi

Charts for the two older discoveries are available on the AAVSO website. Type in either Nova Cep 2014 or TCP J17154683-3128303 (for Nova Scorpii)  in the Star finder box and click Create a finder chart. I’ll update this article as soon as a chart for the new object is posted.

** UPDATE April 2, 2014: This star has been confirmed as a nova. You can print out a chart by going to the AAVSO website and following the instructions above using Nova Cyg 2014 for the star name. On April 2.4 UT, I observed the nova at magnitude 11.o.

Posted on by Jason Major

Bill Nye on Taking Astronomy with Carl Sagan

“This is how we know nature. It is the best idea humans have ever come up with.”
– Bill Nye, Science Guy and CEO of The Planetary Society

In this latest video from NOVA’s Secret Life of Scientists and Engineers, science guy Bill Nye talks about the incredible influence that Carl Sagan had on his life, from attending his lectures on astronomy at Cornell University to eventually becoming CEO of The Planetary Society, which was co-founded by Sagan in 1980.

“I took astronomy from Carl Sagan.” Now there’s a statement that’ll get people’s attention. (It got mine, anyway.)

See more videos in NOVA’s Secret Life series here.

Posted on by Nancy Atkinson

Update on the Bright Nova Delphini 2013; Plus a Gallery of Images from our Readers

The bright new Nova Delphini 2013, as seen from Puerto Rico on August 16th, 03:13ut Credit: Efrain Morales/Jaicoa Observatory.

Since showing itself on August 14, 2013, a bright nova in the constellation Delphinus — now officially named Nova Delphini 2013 — has brightened even more. As of this writing, the nova is at magnitude 4.4 to 4.5, meaning that for the first time in years, there is a nova visible to the naked eye — if you have a dark enough sky. Even better, use binoculars or a telescope to see this “new star” in the sky.

The nova was discovered by Japanese amateur astronomer Koichi Itagak. When first spotted, it was at about magnitude 6, but has since brightened. Here’s the light curve of the nova from the AAVSO (American Association of Variable Star Observers) and they’ve also provided a binocular sequence chart, too.

How and where to see the new nova? Below is a great graphic showing exactly where to look in the sky. Additionally, we’ve got some great shots from Universe Today readers around the world who have managed to capture stunning shots of Nova Delpini 2013. You can see more graphics and more about the discovery of the nova on our original ‘breaking news’ article by Bob King.

The new nova is located in Delphinus alongside the familiar Summer Triangle outlined by Deneb, Vega and Altair. This map shows the sky looking high in the south for mid-northern latitudes around 10 p.m. local time in mid-August. The new object is ideally placed for viewing. Stellarium
The new nova is located in Delphinus alongside the familiar Summer Triangle outlined by Deneb, Vega and Altair. This map shows the sky looking high in the south for mid-northern latitudes around 10 p.m. local time in mid-August. The new object is ideally placed for viewing. Stellarium

If you aren’t able to see the nova for yourself, there are a few online observing options:

The Virtual Star Party team, led by UT’s publisher Fraser Cain, will try to get a view during the next VSP, at Sunday night on Google+ — usually at this time of year, about 10 pm EDT/0200 UTC on Monday mornings. If you’d like a notification for when it’s happening, make sure you subscribe to the Universe Today channel on YouTube.

The Virtual Telescope Project, based in Italy, will have an online observing session on August 19, 2013 at 20:00 UTC, and you can join astronomer Gianluca Masi at this link.

The Slooh online telescope had an observing session yesterday (which you can see here), and we’ll post an update if they plan any additional viewing sessions.

There’s no way to predict if the nova will remain bright for a few days more, and unfortunately the Moon is getting brighter and bigger in the sky (it will be full on August 20), so take the opportunity this weekend if you can to try and see the new nova.

Now, enjoy more images from Universe Today readers:

Nova Delphini 2013 from August 16, 2013 at 0846 UTC. Credit and copyright: Nick Rose.
Nova Delphini 2013 from August 16, 2013 at 0846 UTC. Credit and copyright: Nick Rose.
The bright nova in Delphinus when it was at magnitude 6.1 on August 14, 2013, as see from Yellow Springs, Ohio USA. Credit and copyright: John Chumack/Galactic Images.
The bright nova in Delphinus when it was at magnitude 6.1 on August 14, 2013, as see from Yellow Springs, Ohio USA. Credit and copyright: John Chumack/Galactic Images.
Proving that Nova Delphini 2013 is now a bright, naked-eye object, this fun image shows not only the nova, but the surrounding landscape in Sweden of the photographer, too. Credit and copyright: Göran Strand.
Proving that Nova Delphini 2013 is now a bright, naked-eye object, this fun image shows not only the nova, but the surrounding landscape in Sweden of the photographer, too. Credit and copyright: Göran Strand.
Nova Delphinii 2013 as seen on August 15, 2013. Credit and copyright: Andre van der Hoeven
Nova Delphinii 2013 as seen on August 15, 2013. Credit and copyright: Andre van der Hoeven
Nova in Delphinus from Ottawa, Canada on August 14, 2013. 13 second exposure under heavy light pollution with Nikon D80. Credit and copyright: Andrew Symes
Nova in Delphinus from Ottawa, Canada on August 14, 2013. 13 second exposure under heavy light pollution with Nikon D80. Credit and copyright: Andrew Symes
Image of Nova Delphini 2013, on 15 Aug. 2013, via the Virtual Telescope Project/Gianluca Masi.
Image of Nova Delphini 2013, on 15 Aug. 2013, via the Virtual Telescope Project/Gianluca Masi.
Annotated image of Nova Delphini 2013, as seen from Hawaii. Credit and copyright: Bryanstew on Flickr.
Annotated image of Nova Delphini 2013, as seen from Hawaii. Credit and copyright: Bryanstew on Flickr.

Ralf Vandebergh shared this video he was able to capture on his 10-year-old hand-held video camera to “demonstration of the brightness of the nova and what is possible with even 10 year old technique from hand.”

Posted on by Fraser Cain

Weekly Space Hangout – Aug. 16, 2013

Like your space news, but you just can’t handle reading any more? Then watch our Weekly Space Hangout, where we give you a rundown of all the big space news stories that broke this week.

Host: Fraser Cain

Panel: Brian Koberlein, David Dickinson, Nancy Atkinson, Nicole Gugliucci

Stories:
CIA Comes Clean About Area 51
Elon Musk’s Hyperloop
Space Fence Shut Down
Magnetar Discovered Near the Galactic Core
IAU Updates Their Naming Policy
Bright Nova in Delphinus

We record the Weekly Space Hangout every Friday at 12 pm Pacific / 3 pm Eastern as a live Google+ Hangout on Air. Join us live on YouTube, or you can listen to the audio after the fact on the 365 Days of Astronomy Podcast.

Posted on by Bob King

Bright New Nova In Delphinus — You can See it Tonight With Binoculars

The new nova is located in Delphinus alongside the familiar Summer Triangle outlined by Deneb, Vega and Altair. This may shows the sky looking high in the south for mid-northern latitudes around 10 p.m. local time in mid-August. The new object is ideally placed for viewing. Stellarium

Looking around for something new to see in your binoculars or telescope tonight? How about an object whose name literally means “new”. Japanese amateur astronomer Koichi Itagaki of Yamagata discovered an apparent nova or “new star” in the constellation Delphinus the Dolphin just today, August 14. He used a small 7-inch (.18-m) reflecting telescope and CCD camera to nab it. Let’s hope its mouthful of a temporary designation, PNVJ20233073+2046041, is soon changed to Nova Delphini 2013!

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This map shows Delphinus and Sagitta, both of which are near the bright star Altair at the bottom of the Summer Triangle. You can star hop from the Delphinus "diamond" to the star 29 Vulpecula and from there to the nova or center your binoculars between Eta Sagittae and 29 Vul. Stellarium
This map shows Delphinus and Sagitta, both of which are near the bright star Altair at the bottom of the Summer Triangle. You can star hop from the top of Delphinus to the star 29 Vulpeculae and from there to the nova.  Or you can point your binoculars midway between Eta Sagittae and 29 Vul. The “5.7 star” is magnitude 5.7. Stellarium

Several hours later it was confirmed as a new object shining at magnitude 6.8 just under the naked eye limit. This is bright especially considering that nothing was visible at the location down to a dim 13th magnitude only a day before discovery. How bright it will get is hard to know yet, but variable star observer Patrick Schmeer of Germany got his eyes on it this evening and estimated the new object at magnitude 6.0. That not only puts it within easy reach of all binoculars but right at the naked eye limit for observers under dark skies. Wow! Since it appears to have been discovered on day one of the outburst, my hunch is that it will brighten even further.

I opened up the view a little more here and made a reverse "black stars on white" for clarity. Stars are shown to 9th magnitude. Magnitudes shown for 4 stars near the nova. The nova's precise position is RA 20 h 23' 31", Dec. +20 deg. 46'. Created with Chris Marriott's SkyMap
Here’s a reverse “black stars on white” map some observers prefer for greater clarity. Stars are shown to 9th magnitude. Tycho visual magnitudes shown for 4 stars near the nova. The nova’s precise position is RA 20 h 23′ 31″, Dec. +20 deg. 46′. Created with Chris Marriott’s SkyMap

The only way to know is to go out for a look. I’ve prepared a couple charts you can use to help you find and follow our new guest. The charts show stars down to about 9th magnitude, the limit for 50mm binoculars under dark skies. The numbers on the chart are magnitudes (with decimals omitted, thus 80 = 8.0 magnitude) so you can approximate its brightness and follow the ups and downs of the star’s behavior in the coming nights.

Despite the name, a nova is not truly new but an explosion on a star otherwise too faint for anyone to have noticed.  A nova occurs in a close binary star system, where a small but extremely dense and massive (for its size) white dwarf  grabs hydrogen gas from its closely orbiting companion. After swirling about in a disk around the dwarf, it’s funneled down to the star’s 150,000 degree F surface where gravity compacts and heats the gas until it detonates like a bazillion thermonuclear bombs. Suddenly, a faint star that wasn’t on anyone’s radar vaults a dozen magnitudes to become a standout “new star”.

Model of a nova in the making. A white dwarf star pulls matter from its bloated red giant companion into a whirling disk. Material funnels to the surface where it later explodes. Credit: NASA/CXC/M. Weiss
Model of a nova in the making. A white dwarf star pulls matter from its bloated red giant companion into a whirling disk. Material funnels to the surface where it later explodes. Credit: NASA/CXC/M. Weiss

Novae can rise in brightness from 7 to 16 magnitudes, the equivalent of 50,000 to 100,000 times brighter than the sun, in just a few days. Meanwhile the gas they expel in the blast travels away from the binary at up to 2,000 miles per second. This one big boom! Unlike a supernova explosion, the star survives, perhaps to “go nova” again someday.

Closer view yet showing a circle with a field of view of about 2 degrees. Stellarium
Closer view yet of the apparent nova showing a circle with a field of view of about 2 degrees. Stellarium

I’ll update with links to other charts in the coming day or two, so check back.

See info on the Remanzacco Observatory website about their followup images of the nova.