Exploding star

[arcticpenguin]

http://www.theaustralian.news.com.au/common/story_page/0,5744,6193804%255E2702,00.html

IN a blaze of glory, a humdrum star in the Constellation Monoceros has exploded into a cool supergiant, startling scientists and blasting astronomical theory.
...
But when the outburst faded, an unexpected "echo" of luminous light ringed the star like a halo, an international team of astronomers report today in the journal Nature.
...
Instead, they found the star – "for no completely satisfactory physical explanation" – turned into a luminous cool supergiant.


Great balls of fire!

[scotth]

Pretty cool.

Finding the unexpected is always the most interesting. I suspect we will learn a considerable bit from the observations of this star.

[BillHoyt]

Hmm. It looks like this star jumped into old age ahead of schedule. Premature sunescence?

Cheers,

[Dragonrock]

WHAT!!! Something happened that science didn't expect? All science must be wrong!!! God is real!!

I BELIEVE!!!!!!!

or not.

[garys_2k]

Hmmm, so the Hubble saw a star explode, but I'm confused about what was remaining. One part of the article describes "an unexpected 'echo' of luminous light ringed the star like a halo," while later they said they "found the star – 'for no completely satisfactory physical explanation' – turned into a luminous cool supergiant." So, it's a cool supergiant with a halo?

Not that a halo around a freshly exploded star surprises me, but I wonder why it surprised them.

[scotth]

I think they expected the star to collapse into a white dwarf or a neutron star.

The observed event was much like (if not just like) a nova type explosion. Having a "star" instead of some type of collapsed object wasn't expected.

[DrMatt]

Originally posted by garys_2k

Not that a halo around a freshly exploded star surprises me, but I wonder why it surprised them.

You'd expect STUFF to be there, but you wouldn't necessarily expect to be able to SEE it right away--at least not on the basis of prior observations. Maybe stuff from the explosion is hitting stuff that was already there and forming a shock wave that radiates light... or something.

One problem is that for a halo that distant to be noticeable, it has to be REALLY big (though using the Hubble helps). The size of the region of space affected by the explosion will itself be limited by the speed of light... so there's a limit to the expected rate at which shock waves grow out from a star...

[jj]

Originally posted by DrMatt


You'd expect STUFF to be there, but you wouldn't necessarily expect to be able to SEE it right away--at least not on the basis of prior observations. Maybe stuff from the explosion is hitting stuff that was already there and forming a shock wave that radiates light... or something.

One problem is that for a halo that distant to be noticeable, it has to be REALLY big (though using the Hubble helps). The size of the region of space affected by the explosion will itself be limited by the speed of light... so there's a limit to the expected rate at which shock waves grow out from a star...

Heh. How many rings, i.e. what is there about this star that has it tossing shells of gas every so often?

Just speculation, note, just speculation. When faced with the odd, consider the even first :)

[garys_2k]

Originally posted by DrMatt


You'd expect STUFF to be there, but you wouldn't necessarily expect to be able to SEE it right away--at least not on the basis of prior observations. Maybe stuff from the explosion is hitting stuff that was already there and forming a shock wave that radiates light... or something.

One problem is that for a halo that distant to be noticeable, it has to be REALLY big (though using the Hubble helps). The size of the region of space affected by the explosion will itself be limited by the speed of light... so there's a limit to the expected rate at which shock waves grow out from a star...
Ah, thanks! I see what you mean.

This confusing cosmological conundrum was cause by God, who is protesting the US led war on Iraq in His inimitable fashion. You'll all kneel before Him...

[jj]

Originally posted by Estimated Prophet
This confusing cosmological conundrum was cause by God, who is protesting the US led war on Iraq in His inimitable fashion. You'll all kneel before Him...

No, no, no, it was done by Allah to illuminate the downfall of his false prophet Saddamn. :D

Or was it just a ripple in still space-time, where there was no neutron dropped, nor tau to flow?

[The Bad Astronomer]

The star went nova, and emitted a flash of light. As the photons move out from the star, they light up material around it. I have not read the press release carefully, but the material lit up may have been from the star itself, but that's not always the case. The light pulse from Supernova 1987A lit up junk for hundreds of light years (see here, for example (http://www.ast.cam.ac.uk/AAO/images/captions/aat066.html)). The gas being lit up was not physically associated with the supernova.

The idea of light echoes has been around a long time, Nova Persei in 1901 gave them off. There is a journal paper from the 1920s describing the math; I referenced it in my thesis. :-)

Originally posted by The Bad Astronomer
The star went nova, and emitted a flash of light. As the photons move out from the star, they light up material around it. Blah blah blah...

Fu**in' know-it-alls...:p

[chance]

V838 was classified as “N?” type variable.

Description follows:

Novae. Close binary systems with orbital periods from 0.05 to 230 days. One of the components of these systems is a hot warf star that suddenly, during a time interval from one to several dozen or several hundred days, increases its brightness by 7-19 mag in V, then returns gradually to its former brightness over several months, years, or decades. Small changes at minimum light may be present. Cool components may be giants, subgiants, or dwarfs of K-M type. The spectra of novae near maximum light resemble A-F absorption spectra of luminous stars at first. Then broad emission lines (bands) of hydrogen, helium, and other elements with absorption components indicating the presence of a rapidly expanding envelope appear in the spectrum. As the light decreases, the composite spectrum begins to show forbidden lines characteristic of the spectra of gas nebulae excited by hot stars. At minimum light, the spectra of novae are generally continuous or resemble the spectra of Wolf-Rayet stars. Only spectra of the most massive systems show traces of cool components.

Some novae reveal pulsations of hot components with periods of approximately 100 s and amplitudes of about 0.05 mag in V after an outburst. Some novae eventually turn out to be eclipsing systems. According to the features of their light variations, novae are subdivided into fast (NA), slow (NB), very slow (NC), and recurrent (NR) categories.

[garys_2k]

This is the lead story in this month's Nature issue, and includes this photo of the star:

http://www.nature.com/nature/nuimages/030327cover.jpg

The gist of it is that the dust surrounding the star is likely from past eruptions, but the nature of the eruption(s) is unknown.

[Jim_MDP]

Originally posted by Dragonrock
WHAT!!! Something happened that science didn't expect? All science must be wrong!!! God is real!!

I BELIEVE!!!!!!!

or not.

Heh heh...


http://www.satirewire.com/news/aug02/jupiter.shtml

:D