Attention all astronomers! There is a new Type Ia supernova that has been seen in the nearby spiral galaxy M101, and it’s very young — currently only about a day old! This is very exciting news; getting as much data on this event as possible is critical.
Most likely professional astronomers are already aware of the supernova, since observations have already been taken by Swift (no X-rays have yet been seen, but it’s early yet) and Hubble observations have been scheduled. Still, I would urge amateur astronomers to take careful observations of the galaxy.
[As an aside, I'll note that this supernova won't get bright enough to see naked eye and poses no threat at all to us here on Earth. It may be visible in decent-sized telescopes, though, and as you'll see this may be a very important event in the annals of astronomy.]
So why is this a big deal?
First of all, a supernova is an exploding star — one of the most violent events in the Universe. There are different kinds of supernovae, but a Type Ia occurs, it’s thought, when a superdense white dwarf — the remnant core of a dead star — siphons material off a companion star. If enough material piles on top of the white dwarf, it can suddenly start to fuse hydrogen into helium. This starts a runaway effect, and the entire star explodes. This supernova can release so much energy it can actually outshine its host galaxy! If you want more details, I’ve written about Type Ia supernovae before: Astronomers spot ticking supernova time bomb and Dwarf merging makes for an explosive combo.
So this kind of supernova is incredibly bright, making them easy to spot over vast distances. These events are very important, because we think that each Type Ia supernova is very similar in the way it explodes, making them useful as benchmarks in gauging distances to very distant galaxies. In fact, it is the study of these explosions that has helped us nail down how fast the Universe is expanding, and also led to the discovery of dark energy. Clearly, the more we know about them, the better.
M101 is a spiral galaxy only about 25 million light years away, making it one of the closest big spirals in the sky. It’s also huge, boasting a trillions stars, ten times the mass of our Milky Way. You can read all about it in an earlier post featuring the image at the top of this article.
Given M101′s close distance, this new supernova will be relatively easy to study. And the best part is that the exploding star was caught young: most of the ones we see are far away, and too faint to be seen until they start to reach their maximum brightness after a few days. Getting data on them early is absolutely critical for understanding them, and it’s the hardest part of all this. I am not exaggerating to say this new supernova could be a linchpin in our understanding of these events.
Interestingly, Hubble took images of this galaxy in 2002, and astronomers dug up the archived images and looked at the spot of the supernova to see if anything was there back then. Nothing shows up in the blue filter, but in the red (shown here) there are two stars very close to the position of the future supernova (the circle is centered on the best measurement of the supernova’s position). From their brightness and color, both of these stars are red giants, stars like the Sun but near the ends of their lives. That would fit with the Type Ia supernova: red giants are so big that if there’s a white dwarf nearby, it could suck up their matter and start the chain of events that led to its doom. Further observations may pin this down. If one of these stars is what fed the supernova, that’s seriously cool; there are only a handful of supernova progenitor stars that have ever been seen*.
All in all, this is pretty much a big deal. The galaxy is close, pretty, a bit odd, and is hosting the nearest Type Ia supernova seen in decades which was caught when it was less than a day old. I’m excited! I know a lot of telescopes will be aimed at the northern skies over the next few days, and I’ll be very interested to find out what they see.
Image credits: Hubble M101 image: NASA, ESA, K. Kuntz (JHU), F. Bresolin (University of Hawaii), J. Trauger (Jet Propulsion Lab), J. Mould (NOAO), Y.-H. Chu (University of Illinois, Urbana), and STScI; Type Ia art: NASA/CXC/M.Weiss; Hubble image: NASA/ESA/Hubble. Tip o’ the dew shield to paulwarren73.
* Technically, if one of the red giants was behind this event, it wasn’t the star that actually exploded — the white dwarf which actually blew up was far, far too faint to be seen here. Still, very cool.
There he is, the Carl Sagan of my generation.

The US company has confirmed it will use the Atlas 5 rocket to test its CST-100 ship on three flights in 2015.
An unmanned capsule will be used on the first and second launches. On the third, Boeing test pilots will take the vessel to the space station.
The plan is dependent on a successful development programme and the availability of sufficient funding.
Boeing is one of a number of companies being encouraged by the US space agency (Nasa) to develop a commercially operated crew transport service to and from low-Earth orbit.
The idea is that Nasa and other space agencies around the world would buy seats in these vehicles to get their people to the international orbiting platform and other destinations that might one day include privately run space labs and hotels.
Last month, Nasa retired its space shuttles, partly on the grounds of cost - they were hugely expensive to maintain.
The agency believes that by handing operational responsibility to the commercial sector, the price of getting into low-Earth orbit can be reduced substantially.
It is giving Boeing financial support to help it develop the CST-100 ship.
The conical design will be capable of carrying up to seven individuals.
The choice of the Atlas 5 as the CST-100's launcher is not a major surprise. It has an excellent record - 27 flights with a 100% success rate.
It also happens to be operated by a company that is part-owned by Boeing called United Launch Alliance (ULA). However, Boeing says that relationship played no part in the decision to use Atlas; it was simply that Atlas was deemed the best rocket for the task.
"Our approach is to produce a reliable spacecraft built on existing simple systems and then integrate that with a proven launch vehicle, all focussed on putting in place a very safe system, one that will be reliable and that can be operational as soon as practical so that we can start flying US crew from US launch sites post the shuttle era," said John Elbon, vice president and programme manager of Boeing's Commercial Crew Programs.

The year 2015 will see the Atlas launch the capsule three times.
The first flight will put the ship in orbit. The second will take the CST-100 part-way towards space before practising an abort.
In this procedure, the capsule will push itself away from the rocket mid-flight as if there were some problem on the rocket. This will be a critical test of astronaut safety features built into the capsule in the event of an emergency.
Assuming these demonstration flights go well, the third mission will see Boeing test pilots take the CST-100 all the way to the International Space Station.
The CST-100 would then be ready for commercial service starting in 2016.
Boeing says the two pilots it plans to use on the manned mission in 2015 will emerge from a selection process that is already under way.
"We're actually interviewing now for the first one," said Mr Elbon. "I would like to get one on board so that they can be part of the design process and influence it from an operator's perspective."
The decision of Boeing to use the Atlas 5 follows hard on the heels of a recent agreement signed between Nasa and ULA to prepare the Atlas rocket for astronaut launch duties.
This work will determine which components on the Atlas already meet Nasa's stringent requirements for human spaceflight and which elements might need to be upgraded.
ULA is also developing an emergency detection system that would be placed inside the Atlas to give warning of a major malfunction. In addition, ULA needs to prepare a gantry structure that would allow astronauts to get in and out of a capsule when it is mounted on top of an Atlas at its launch pad.
"ULA will provide launch services from Space Launch Complex 41 at Cape Canaveral Air Force Station," explained George Sowers, ULA's vice president of business development.
"We will use the Atlas 412 configuration, which means it has a single solid rocket booster [attached to its liquid-fuelled core stage] and a dual engine Centaur upper stage.
"We believe the Atlas 5 provides the earliest possible initial launch capability for commercial crew and we'll be ready to support Boeing with both un-crewed and crewed test flights in 2015."