Thursday, January 23, 2014

Undergrads discover closest supernova since 1980s

It was named SN 2014J

If you're an undergrad and you are being shown a telescope, watch carefully. You may very well find one of the most important dots that temporarily appears in the skies. The BBC was among the first ones that informed the public about the new observation:
Nearby supernova dazzles astronomers
The supernova was spotted during a telescope class at the University of London Observatory led by Steve Fossey who may be expected to lick enough milk from the kids' discovery to build his own Milky Way. That's what I call good luck. Since that time, the new supernova was confirmed by the International Astronomic Union.

Realtime Twitter buzz about the exploding star

The beast is located in Messier82 or M82, a prototype (irregular) nearby starburst cigar galaxy that is 12 million light years away from us (the supernova has the same distance, of course). That galaxy is about 5 times more luminous than our Milky Way homeland.

Type Ia supernovae always reach pretty much the same peak luminosity – that is why they are used as "standard candles" in cosmological measurements. The constancy occurs because the supernova explosion occurs when a hungry, accreting white dwarf (not to be confused with the small fat white old U.S. man who has caught Lenin's disease from too much sex) exceeds a tipping point of its mass.

It follows that the type Ia supernovae's peak luminosity is pretty much a decreasing function of the distance. The closer it is, the brighter it is. And this undergraduate 2014 supernova is the closest one since the late 1980s when, SN 1987A supernova which was so hot for astroparticle physicists (yes, the number is the year) occurred just 168,000 light years away from us, in a dwarf galaxy, but it was a type II-P (unusual) supernova. Well, type IIb SN 1993J supernova was 11 million light years, slightly closer than the new one, but they may be talking about type Ia ones only, anyway.

The host galaxy: before and after. Can you spot the difference? No, the supernova is neither the horizontal line nor the vertical line!

For another comparison, another type Ia supernova, SN 2011fe, was about 21 million light years from us which is about twice as much as the new undergraduate supernova. The difference between the distances is not "stunning" but the kids have found the recent winner, anyway. See a list of notable supernovae.

Could a supernova destroy life on Earth, you may ask?

The X-rays and gamma-rays would be very harmful for the ozone layer etc. if the supernova were up to 50 light years from us. That's many billions times smaller a volume than where we are routinely seeing supernovae. Moreover, we are pretty sure that there is no potential supernova this close, so don't worry.

No comments:

Post a Comment