Astronomy Question !!!!
Moderator: Alyrium Denryle
Astronomy Question !!!!
Yes, I have a question on what is the most accurate measurement of an object that is over 6000 light years away.
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Wyrm
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I'm not sure of the exact distance that can be measured using highly accurate paralax methods, but the HIPPARCOS survey is your best bet here. I believe it's accurate for stars within a few thousand parsecs. It might suit you, given an appropriate definition of "few."
As for other methods, if the star is in a cluster with a standard candle (like a Cephied or an RR Lyrae), that can give you an accurate measure. Less accurate is to find the star's position on the HR diagram and compute its absolute magnitude, and from it, find it's distance using the inverse square law. If the star in question is a standard candle, you've got it made in the shade.
As for other methods, if the star is in a cluster with a standard candle (like a Cephied or an RR Lyrae), that can give you an accurate measure. Less accurate is to find the star's position on the HR diagram and compute its absolute magnitude, and from it, find it's distance using the inverse square law. If the star in question is a standard candle, you've got it made in the shade.
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wilfulton on Bible genetics: "If two screaming lunatics copulate in front of another screaming lunatic, the result will be yet another screaming lunatic.
"SirNitram: "The nation of France is a theory, not a fact. It should therefore be approached with an open mind, and critically debated and considered."
Cornivore! | BAN-WATCH CANE: XVII | WWJDFAKB? - What Would Jesus Do... For a Klondike Bar? | Evil Bayesian Conspiracy
It's a special case, but SN1987A is an excelent example of an object definitively older then the Genesis creation myth. The distance measurement itself is quite elegantly arrived at: the distance between the remnant of the star and the gas ring from the supernova event can be measured by contrasting a brightening of the stellar remnant and the reflection of this light from the gas ring, the angular distance between the two is known, and simple trigonometry can thus arrive at the distance, which is ~186,000 LY. It is described quite nicely in this YouTube video.
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Wyrm
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For standard candles, only if the standard candle's absolute luminosity can be determined within 1%. As I recall, none are. Cosmic scatter kills this level of detail.
As for the paralax method, only if the paralax shift can be determined better than 1 part in 600000. Which isn't going to happen, not even with HIPPARCOS.
As for the paralax method, only if the paralax shift can be determined better than 1 part in 600000. Which isn't going to happen, not even with HIPPARCOS.
Darth Wong on Strollers vs. Assholes: "There were days when I wished that my stroller had weapons on it."
wilfulton on Bible genetics: "If two screaming lunatics copulate in front of another screaming lunatic, the result will be yet another screaming lunatic."
SirNitram: "The nation of France is a theory, not a fact. It should therefore be approached with an open mind, and critically debated and considered."
Cornivore! | BAN-WATCH CANE: XVII | WWJDFAKB? - What Would Jesus Do... For a Klondike Bar? | Evil Bayesian Conspiracy
wilfulton on Bible genetics: "If two screaming lunatics copulate in front of another screaming lunatic, the result will be yet another screaming lunatic.
"SirNitram: "The nation of France is a theory, not a fact. It should therefore be approached with an open mind, and critically debated and considered."
Cornivore! | BAN-WATCH CANE: XVII | WWJDFAKB? - What Would Jesus Do... For a Klondike Bar? | Evil Bayesian Conspiracy
