Caught in the Act: Astronomers See Supernova As it Explodes
Written by Nancy Atkinson
The Swift satellite has made another fortuitous observation. This time, and for the first time ever, astronomers have caught a star in the act of going supernova. These stellar explosions have been observed before, but always after the fireworks were well underway. "For years we have dreamed of seeing a star just as it was exploding, but actually finding one is a once-in-a-lifetime event," says Alicia Soderberg, from Princeton University, who is leading the international group studying this explosion. "This newly born supernova is going to be the Rosetta Stone of supernova studies for years to come."
In January of 2008 Soderberg was expecting to study a month-old supernova that was already underway. But as she and her assistant studied the X-ray emissions conveyed from space by NASA's Swift satellite, they saw an extremely bright light that seemed to jump out of the sky. They didn't know it at the time, but they had just become the first astronomers to have caught a star in the act of exploding.
"In the old days — last year — people found supernovae by their optical light and then started to study them to understand which stars blow up, what the mechanism is and what they produce," said Robert Kirshner, a professor of astronomy at Harvard University. "But this is something new — the X-rays come right at the beginning and provide a very early alert to the event."
Soderberg regards the discovery as a case of extreme serendipity. The satellite was pointing in the right place at the right time, she said, because she had asked Neil Gehrels, Swift's lead scientist at NASA's Goddard Space Flight Center to turn it that way to look at another supernova. And while she was away lecturing, she had asked her colleague, Edo Berger, to keep an eye on the data for her.
"It's a really lucky chain of events — a surprise," said Soderberg, who is leading the group studying the explosion. "It was all over in a matter of minutes."
Other observatories also turned their telescopes toward this stellar explosion, making detailed observations of the event, including the Hubble Space Telescope, the Chandra X-ray Observatory, Palomar's 60- and 200-nch telescopes, the Gemini Observatory and Kitt 1 Telescope in Hawaii, and the Very Large Array and Apache Point Observatories in New Mexico. This will allow a very detailed study of this event.
A typical supernova occurs when the core of a massive star runs out of nuclear fuel and collapses under its own gravity to form an ultradense object known as a neutron star. The newborn neutron star compresses and then rebounds, triggering a shock wave that plows through the star's gaseous outer layers and blows the star to smithereens. Until now, astronomers have only been able to observe supernovae brightening days or weeks after the event, when the expanding shell of debris is energized by the decay of radioactive elements forged in the explosion.
Original News Source: Princeton University Press release
Filed under: Astronomy
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May 21st, 2008 at 10:29 am
This is pretty phenomenal news. Funny how most human discoveries happen by accident. I wonder what they'll find out from this. With the telescopes they have now and the ones they're bringing out within the next decade, it'll be every stargazers wet dream.
May 21st, 2008 at 12:38 pm
It was lucky indeed. I doubt that anything new will be learned from it though. Maybe only "confirmed" theories.
May 21st, 2008 at 12:57 pm
Scientists always find ways to plumb data out of every observation years after the results. Continue to observe this for years now, its going to all be catalogued from the very moment it went off, thats wnderful and this really is a unique and historic event.
May 21st, 2008 at 2:53 pm
Dumb question, but wasn't Supernova 1987A the first to be "caught in the act" of exploding?
The neutrino burst from 1987A (in the Large Magellanic cloud) was detected in the US and Japan, and the time of the optical burst was bracketed by observations from Albert Jones in New Zealand and Ian Shelton at Las Campanas in Chile.
I would argue the detection of the neutrino burst constitutes a star "caught in the act" of going supernova.
Something for the historians to sort out, I suppose.
Still, this is a wonderful discovery. Can't wait to hear what they learn from this!
May 21st, 2008 at 3:25 pm
El satélite Swift hizo otra observación fortuita. En esta oportunidad, y por primera vez en la historia, los astrónomos captaron una estrella en el momento de pasar a supernova. Se habÃan observado antes estas explosiones estelares, pero siempre después de mucho tiempo de comenzados los fuegos artificiales. [...] Fuente: Nancy Atkinson para Universe Today.
May 21st, 2008 at 5:30 pm
"Other observatories also turned their telescopes toward this stellar explosion, making detailed observations of the event, including the Hubble Space Telescope, the Chandra X-ray Observatory, Palomar's 60- and 200-nch telescopes, the Gemini Observatory and Kitt 1 Telescope in Hawaii, and the Very Large Array and Apache Point Observatories in New Mexico. This will allow a very detailed study of this event."
Great to see that this much firepower was brought to bear on the event! hopefully when the Large Synoptic Survey Telescope goes online, these sort of amazing observations will become much more frequent…
May 21st, 2008 at 9:47 pm
You are correct, Brian. I'm not a scientist, but I do remember 1987A being proclaimed as exactly that. In fact, if I remember correctly, it was considered so because they caught it before it peaked.
I guess we will find out that this is a "first" based on some other criteria.
With that said, it may be that they have determined that SWIFT has been continuously trained on that area starting prior to the event, even if not focused on the original star itself. I guess that would beat out the previous first.
May 21st, 2008 at 10:46 pm
"Dumb question, but wasn't Supernova 1987A the first to be "caught in the act" of exploding?"
Yeah – I reckon you could debate this point with support going either way. My take on it is that, while the neutrinos were detected at three separate observatories, they didn't quite know what they had seen for a little while. The 'discovery' was attributed to a visible light observation by Shelton, I think.
In the latest case, the X-ray burst arrived and was observed, signaling the imminent arrival of the optical component of the radiation. After reading the paper in question in 'Nature', the authors state "…Simultaneous observations of the field with the co-aligned Ultraviolet/Optical Telescope (UVOT) on board Swift showed no evidence for a contemporaneous counterpart [to the X-ray outburst]. However, UVOT observations just 1.4 h after the outburst revealed a brightening ultraviolet/optical counterpart. Subsequent ground-based optical observations also uncovered a coincident source."
So I guess they're claiming that, unlike for sn1987a, they witnessed the first actual supernova light-curve rising from the baseline to full intensity from the very first moment the optical signal came through .
May 22nd, 2008 at 4:04 am
I'm applying for a PR job with Nasa
. All this emphasis on "accident" or "serendipity" is totally missing the mark when it comes to the positive side of this astounding discovery. What is the positive side? Da SWIFT, da SWIFT boss! Had the scope not been funded and launched – there would be no "accident".
May 22nd, 2008 at 7:01 am
Concerning the "looking at it when it exploded" debate.
If I remember correctly, the neutrino signal from 1987A was not discovered until several days after the optical SN discovery. I mean, it did happen before Shelton's observation, but there was no real-time alert.
Actually, the Caltech team is twisting history here quite a lot… Every long Gamma-Ray Burst is an eminent signal of an exploding star. And the best claim for immediate detection is XRF 060218/SN 2006aj. In that case, the X-ray Outburst actually triggered Swift (with XRO 080109, it was discovered in ground analysis hours later), and both Swift's UVOT as well as the ROTSE robotic telescope discovered optical emission just 100 seconds or so after the begninning of the outburst. But that was not discovered by Caltech, so they are downplaying it…
@Astrofiend: This is not the only team reporting observations!! Do check out these papers too:
http://arxiv.org/abs/0805.1188
(This team was the first to identify that the new optical source was, indeed, a supernova)
http://arxiv.org/abs/0805.2201
(This team has sensitive limits just hours before the X-ray outburst, and also were the first to correctly identify this as a Type Ib SN, not Ic.)
May 22nd, 2008 at 11:17 am
pretty wild. i know nothing about telescope technology, but when could we expect an instrument that could really see more of the fine details in a discovery like this? or is that only available by sending out probes?
May 22nd, 2008 at 12:33 pm
I don't know why everyone is so excited about this. This thing happened thousands and thousands of years ago. :/
By now, its remnants are probably the shape of a beer can.
May 25th, 2008 at 1:37 am
Whoa
August 19th, 2008 at 3:41 pm
I believe it was Oscar Duhalde who was the first to see SN1987A on that fateful February night. Only after he and Ian Shelton submitted their discovery had the Neutrino detectors been checked.