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Hubble Chronicles Mysterious Outburst
An eruptive star that brightened to 600,000 times its initial intensity and briefly outshone all others in the Milky Way Galaxy has astronomers amazed and puzzled over what happened...The star, named V838 Monocerotis, has suddenly grown so big that if placed in the center of our solar system it would engulf Jupiter.
Maybe it's going through puberty? Explosive growth without getting any brighter =;-]
- In the beginning there was nothing, and then it exploded
While I was RTFA, I pretty much expected that this "sudden" event would be revealed as sudden only when measured in geologic or cosmic time; say, a few thousand millenia or so. The fact that this happened over only a few months is fascinating.
According to the article, this happened 20,000 years ago...
*yawn*
My father is a blogger.
This event goes contrary to everything what is known about the star life cycle so far.
New physics just for this star? I doubt it.
One reasonable suggestion without reaching for mysterious new physics is that it is part of a binary system, with a compact object (neutron star, white dwarf or possibly black hole) in a highly eccentric orbit around this main sequence star.
Every x number of years, the compact object skids in on its highly eccentric orbit, and slams through the upper layers of the visible star. Material falls onto compact object, flares up and heats the outer layer of the main sequence star, compact object whizzes out again and is not seen again for another few hundred years or so. The fraction of total mass ejected from the main star is miniscule, so this process does not significantly alter the main star's evolution on the timescale of a few million years, hence the repeated shells of dust seen in these light echoes.
Binary systems of this types have been known about for quite a while (well, on the order of 20 years). The trick is looking for the signature of the compact object, which is a difficult detection.
Dr Fish
42. Stay the fuck away from "V838 Monocerotis" today.
Check.
Well, that's me done for today. Time to troll Slashdot...
Opportunity knocks. Karma hunts you down.
For those who want a screen filling larger image, 1651x1651, it is the subject of today's Astronomy Picture of the Day (APOD).
-Adam
"In fact, at present it is one of the coolest stars known," Bond told SPACE.com.
The astronomer then proceded to slick back his hair and donned a pair of shades, while rythmically snapping the fingers of his free hand.
"Oh, yeah," added Bond.
The angel in the oatmeal.
Hubble took a series of 4 photos, and you all have been looking only at the last of them. Also is a link in case you want large versions of each individual photo, and another for links for all the text, images, and video concerning the event. I'm surprised Doctor Fishboy never pointed this out.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
1. If the star is moving at a certain velocity, then the average velocity of a particle in a cast-off shell of dust will be at the star's velocity. In other words, the star will stay centered in any spherical shell of material it gives off (yes, I know, some neutron stars get kicked out of their nebulae, but that's a far more energetic process). An interstellar wind, if present, would destroy the spherical shape of the nebula.
2. The nebula is acting as a reflector, no doubt, but it is so thin that the star is perfectly visible through it anyway. It's the red star in the photo(s).
3. The only way this could "magnify the apparent brightness" of the star is if the star and nebula were not resolvable as separate objects. Then light reflected from the nebula could be mistaken as light from the star (ignoring spectral techniques). But the photo is of a fully resolved nebula and star. A child could distinguish light from the star vs. reflected light from the nebula.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
I was with Mark (Wagner) and Sumner (Starrfield) when we got the spectra. . .now I'm going to be really pissed if I'm not on the paper since I was the one taking the spectra. . .
But anyhow. . .the spectra is really interesting, there are P Cygni profiles for every emission line in the spectra (P Cygni's look like half a gaussian in emission with a sharp cutoff to be half a gaussian in absorption). This object was actually noticed by people looking at variable stars and then was picked up by some other folks in Arizona which showed the light echos even in the relatively low resolution images we got on the ground compared to our HST ACS images.
It was meant as a joke. But maybe you can make a weapon with which you can expode a sun. Shouldn't be too hard considering the sun is one giant atomic bomb anyway...
If it's easy, it should happen all over the place already through natural processes. This does not seem to be the case (novae and supernovae are quite rare in the grand scheme of things).
Stars are very good at being self-balancing systems. As reaction rate increases, so does photon pressure, which makes the star less dense, which reduces reaction rate. This breaks down only in special cases.
Unstable giant stars, like this star appears to be, are one of those cases. Our sun may end up doing something not very different from this in a few billion years as its core runs out of fuel.
Violent explosions only occur when something overrides fusion-produced photon pressure and the star starts collapsing. This mainly happens when a star runs out of fuel, and stops again when either a new fusion stage starts, or when degeneracy pressure takes over.
Surprise! The "star filter" effect is in the clean, unaltered image. Your small image is just too small to show them. The crosshair produced by each star is a result of diffraction of light in the telescope. Diffraction is the inevitable result of any optical system that isn't infinite in size and is often what limits the resolution of modern telescopes (in the old days it was our messy atmosphere). Diffraction from the aperture of a telescope results in pointlike light sources being resolved as a series of circles surrounding a central dot (Airy disk). The spikes come from the supports that hold the secondary mirror. They are in front of the primary mirror and therefore in the path of incoming light. You might argue that not all stars in Hubble photographs have them. This is because the stars had to be overexposed to capture the much fainter nebula.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
5. Their distance estimate of 6 kpc was a lower limit. If anything it was even further away and brighter.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
Here's a link to Bond's paper in Nature.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show