Late last night the Twitter world was abuzz with news about a supernova having been spotted in the 'Cigar' galaxy, Messier 82 or M82, which is about 11.4 million light-years away. With a brightness of 12th magnitude the stellar explosion quickly became a telescopic target. And, since it was "discovered" early in its explosive outburst, experts estimate the supernova can reach magnitude 8 and thereby become visible with binoculars. Indeed, some Caltech scientists project the supernova will reach peak brightness in the next two weeks.
This supernova is the closest in recent times to have been observed to explode. Prior to this one, there was a star that exploded back in 1987 in the Milky Way's satellite galaxy known as the Large Magellanic Cloud. Reaching magnitude 3, it was labelled SN1987A. Then in 1993, near Bode's Galaxy, or M81, there occurred a supernova, named SN1993J, which reached a maximum brightness of 10.5. Afterwards, in 2011, another star exploded in constellation Canes Venatici's spiral galaxy M51, about 23 million light-years away.
By comparison, the supernova observed last night, is at a distance from Earth that makes it "practically in our backyard by astronomical scales."
Because the supernova is roughly 11.4 million light-years away, that means the star in fact exploded 11.4 million years ago, and we are just seeing its effect now. That is, light from that past event traveled across the universe and has just arrived in Earth's line of sight.
Scientists are excited about this supernova because it was "caught young" -- thus making it possible for us to find clues to the explosion. Pre-imaging of M82 by the Hubble Space Telescope is being viewed so that the astronomical community can directly see the star that had gone supernova.
The star explosion was "discovered" last night (Tuesday, January 21st) by University College London (UCL) tutor Dr. Steve Fossey and his students as they imaged the galaxy while utilizing their university's observatory at Mill Hill in north London.
Russian astronomers I. Molotov and L. Elenin then confirmed the finding with a 0.4-meter telescope at the ISON-NM Observatory in the city of Mayhill NM. Molotov and Elenin provided the measurement of the supernova's magnitude as 11.7.
Thanks to Twitter the news spread like wildfire, especially amongst the night owl community of astronomers who quickly began comparing notes and even scoured old Hubble images to try pinpointing the star that went supernova.
According to University of Oxford's Chris Lintott: "This is a nearby supernova, by astronomical standards, and so we have the chance to learn about the causes and processes that drive these spectacular events. Early indications are this might be a type Ia -- they're the type we use to measure the expansion of the Universe and so that would be especially exciting."
Meanwhile, Australia's supernova specialist, Brad Tucker, who works at Mount Stromlo Observatory, added: "Any supernova that we catch early will help us understand how they explode and what the star is that explodes, as the earlier we can observe a supernova, the more clues we get. For instance, at very early times, between an hour and a couple of days, we may be able to see the shockwave of the explosion propagate through the star, much like the shockwave from a nuclear bomb occurs before the nastiness follows."
When prodded as to why this supernova is significant, Tucker continued: "This type of supernova is a type Ia, the ones we use to measure distances across the Universe. This use was what led to the 2011 Nobel Prize -- the discovery that the expansion of the Universe is accelerating, which implies the Universe consists of 70 percent Dark Energy, something we have no idea about."
Besides being the type of supernova scientists use to study dark energy, Tucker enthused about this supernova being a 'reddened' Ia, which is a type of supernova occurring in a dusty environment. He said: "By knowing there is lots of dust, we can analyze how the dust is impacting the colors of the SN and therefore the distance measurements, and use this to calibrate other SN. In short, this is the Holy Grail."
Supernovae are always welcomed because of the opportunities they provide to study neutrinos. However, a Type Ia -- caused by an exploded white dwarf that accreted too much matter -- emits fewer neutrinos than other types of supernovae. Hence, researchers are instead focusing on the possibility of this supernova helping to provide clues to SN-generated gamma rays.
The first supernova ever seen on Earth was documented by the Chinese two thousand years ago in 185 AD. Not until November 11, 1572 would a European witness a supernova -- the astronomer who did so was then 26-year-old Tycho Brahe.
Stargazers are encouraged to make time tonight to view this type Ia stellar phenomenon, which is binocular-visible. Galaxy M82 can be found near Ursa Major, or the Big Dipper. As soon as the sky gets dark Ursa Major, or the Big Dipper, shall already be aloft in the northeastern sky, thus making it possible for stargazers to observe the supernova spectacle at any time of the night.