Talk:Pistol Star

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Image[edit]

There's a nice image of the Pistol Star that could be used here and at Pistol Nebula, credited to Don Figer (UCLA) and NASA: [1]. However, it's not clear whether Dr. Figer or UCLA claim copyright on it. Wmahan. 05:26, 20 September 2005 (UTC)

The original Hubble press release image [2] is copyright free. But other images are copyrighted, unless explicitly otherwise mentioned.--Jyril 17:32, 20 September 2005 (UTC)

OK, I've added the image from the press release. Wmahan. 20:11, 20 September 2005 (UTC)

Luminosity[edit]

I just did a double revert of the statement that this star radiates as much energy "in 1 sec" as the Sun in a year. It was absurdly inconsistent with the luminosity claimed, as there are >31,500,000 seconds in a year, so I deleted the sentence. However, I tracked it back to a change in March from "in 20 sec", which is more reasonable, so I restored that.

Notice that there are typically big uncertainties on luminosity, as it involves photometry (±1% is not bad), spectral energy distribution (ie, you gotta measure that brightness accurately at several wavelengths), distance (and a 1% error in distance means a 2% error in luminosity), and extinction (which also has to be known as a function of wavelength). All these problems get piled on top of one another for bolometric luminosity. Wwheaton (talk) 21:22, 9 April 2009 (UTC)

Let's also not forget that, of all things, this is a Luminous Blue Variable star we're talking about, the key word being "variable." Hence, its luminosity is not going to ever be consistent, adding whole new levels to the uncertainty involved. It's perhaps a marvel that astronomers have managed to get a decent idea at all, even when they're working in such large increments. Nottheking (talk) 07:33, 22 May 2009 (UTC)
Just to clarify, the luminosity of LBVs *is* fairly constant. Their temperature and spectral type varies dramatically during their normal outbursts every few years, and their visual brightness also varies somewhat, but the bolometric absolute magnitude hardly budges. The very rare great outbursts (as typified by eta Car) do cause an increase in total luminosity, but it is possible that these are an unrelated type of event that just happens to have been seen in LBVs. All LBVs, and many similar stars, do show very small amplitude variation in luminosity but not enough to worry about given the level of uncertainty in the numbers. — Preceding unsigned comment added by Lithopsian (talkcontribs) 13:56, 1 July 2012 (UTC)

Star History[edit]

Not an expert, but it sounds misleading to point out that a star is 25,000 light years from Earth, then mention presumed activity from 4,000 to 6,000 years ago. My point is, we wouldn't be able to see the presumed outbursts for another 19-21,000 years from now. I assume it is meant that the presumed activity would have been witnessable 4-6K years ago. Perhaps it is understood in "star talk" but it seemed inconsistent and I leave it to more expert minds to decide Delibebek (talk) 17:29, 23 April 2009 (UTC)

Right—the (fairly standard) convention is to use "Earth arrival time" when talking about observations of astronomical bodies. This distinction becomes quite critical for JPL when talking about spacecraft event times.
The location of gamma-ray bursts by precision timing of observations from distant spacecraft went through an interesting period of confusion in the 1970s until this issue got straightened out. It turned out you needed to reduce all the observed times to UTC in the Earth's Lorentz frame, but of course at the spacecraft, to get the right answer, even if none of the spacecraft were anywhere near the Earth in position or velocity! And, I think, then one had to correct for stellar aberration as if the observations were made on the Earth!! Strange but true. Wwheaton (talk) 19:29, 23 April 2009 (UTC)