Every day, nay, many times every day, somewhere in the visible universe a star goes BOOM!
If we humans are lucky, an automated search like the
Palomar Transient Factory (PTF), ably assisted by the eyes and brains of zooites, will catch such a
falling star (and put it in your pocket) supernova, and analyze its
dying scream light curve and spectrum.
On July 11th, 2010 the PTF and zooites saw this:
I call this the "Oops" supernova. First, its formal name is PTF1
0ops (OK, PTF10ops, and the symbol for zero is not the same as that for a capital O
you'll give me that they do look the same though, won't you?); but mainly because it seems to be a supernova in the middle of nowhere!
Supernovae, as all zooites surely know, can be classified into several different types, according to the shape of their light curve (i.e. intensity vs time, as measured in some clearly defined part of the electromagnetic spectrum, usually in the visual) and features of their spectra (e.g. the presence of hydrogen lines). One such type is the Ia (SNe Ia), and these are extremely useful, because they are particularly bright 'standard candles'; if you see one in some distant galaxy, you can, from analyzing its light curve and spectrum, get a pretty good estimate of the distance to that galaxy (you know it's the same galaxy as the SNe because the redshifts will be very similar; of course, you may not always be so lucky as to get a good enough spectrum or light curve ...).
About a decade ago, an unusual SNe Ia was discovered; since then several more like it have been found. Today these are called the 91bg-like family ... no prize for guessing that the first one discovered is named 1991bg! Since then at least one other type of peculiar SNe Ia has been found.
All this is both fascinating and somewhat disturbing, because we've never seen the object(s) that later went boom and looked, from a vast distance, like SNe Ia; i.e. no Ia progenitor has ever been seen. Theoretical models strongly suggest these progenitors are white dwarf stars which have had too much mass dumped on them, from their companion binary star, or that they are violent merger/collision of a pair of white dwarf stars.
That's what makes the Oops supernova so interesting; not only is it quite unlike (almost) any other Ia ever seen, but it seems to an orphan, a star without a galaxy to call home!
As luck would have it, the Hubble took a peek at it using STIS (the Space Telescope Imaging Spectrograph), while it was still young; its unusual features made it a very hot property, so it got a lot of attention from astronomers round the world, and a great many observations were made.
And it does seem like it might be a rare sub-type of Ia, one that occurs far from its host galaxy, in an environment low in metals, and among stars that may be as old as 13 billion years. However, at this stage, there are far more questions than answers, and what the progenitor of these rare SNe Ias is is really a mystery. Here is that environment (source for the second image? see below):
I'm saving the best for last;
here is robert gagliano's announcement of the zooite discovery ("
Discoverers: chrostek, ElisabethB, galaxirose, rphubbard, Alexandar Micic, volatile36, DIaspro, marek kaluzny, ciberjohn, graham d, John P Langridge"), but here's the best bit:
PTF10ops was discovered by the PTF using the Galaxy Zoo Supernovae citizen science project1 (Smith et al. 2011) on 2010 July 11.4 (UT dates are used throughout) at RA: 21:47:33.57, dec.: +05:51:30.3 (J2000) using the PTF search telescope, the Samuel Oschin 48-in telescope (P48) located at the Palomar Observatory.
[...]
1 PTF10ops discoverers: Aleksandar, Henryk Krawczyk, ciberjohn, Giovanni Iezzi, Elisabeth Baeten, Sarah Zahorchak, Graham Dungworth, John P Langridge, Marek, Robert Hubbard, Volatile
And:
7 ACKNOWLEDGMENTS
[...]
This publication has been made possible by the participation of more than 10,000 volunteers in the Galaxy Zoo Supernovae project, http://supernova.galaxyzoo.org/authors.
These quotes are from "
PTF10ops - a subluminous, normal-width lightcurve Type Ia supernova in the middle of nowhere",
Maguire et al. (2011), as is the image above [1]
Zooites, take a bow.
[1] Figure 1:
An image of the field of PTF10ops (located at the centre of the crosshairs) taken with the WHT+ACAM with 0.25 arcsec per pixel. The largest galaxy located in the upper left quadrant has a projected separation from PTF10ops of 115.2′′ (1.92′), which at zcmb = 0.062 corresponds to 148.3 kpc.
(Alice has connection challenges, and I'm standing in for her today)
Edit: changed the 'clapping hands' smilie/emoticon
