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The North Star has been a guiding light for countless generations of navigators. But a new study reveals that its distance to Earth may have been grossly overestimated.
In fact, the North Star—also called Polaris—is 30 percent closer to our solar system than previously thought, at about 323 light-years away, according to an international team who studied the star's light output.
Using Russia's 6-Meter Telescope, the researchers were able to calculate the North Star's distance from our solar system by analyzing its spectrum of light and obtaining data on its temperature and changes in intrinsic brightness over time.
That significantly revises the previously accepted value of 434 light-years, which was obtained by the European star-mapping satellite Hipparcos in the 1990s.
Originally posted by MagicWand67
Scientists Discover Nibiru is Heading This Way
Polaris is the closest Cepheid variable to Earth so its physical parameters are of critical importance to the whole astronomical distance scale.[3] It is also the only one with a dynamically measured mass.
Originally posted by minnow
so Nibiru is closer than we thought, i knew it!!
Originally posted by MagicWand67
Scientists Discover Nibiru is Heading This Way
by almost a third!
so, what is it about the north star that is is so depended on in our sky, physically?
why is it so bright and so relatively fixed in our sky? does it have a constellation, and what else is known about it that is interesing?
and is the only breakthrough about the north star or were they wrong about other north star things in the past, too?
Originally posted by MagicWand67
Maybe another member here can assist us.
Being that it is the closet star to us. I think that accounts for it's brightness.
Originally posted by MagicWand67
reply to post by minnow
Sorry, I told you this is not my area of expertise.
Let me correct that.
" Polaris is the closest Cepheid variable to Earth "
Whatever that means.
The North Star's claim to fame is due to its fixed position in the sky for Northern Hemisphere observers—aligned with Earth's northern axis—while other stars appear to wheel around it.
Known to fade and brighten over a four-day period, this celestial beacon of true north is considered the closest and brightest member of a class of stars called Cepheids that change in brightness over time. (See star pictures.)
The star is also a type of cosmological yardstick used by researchers to measure great cosmic distances out to billions of light-years.
For this reason, it's vital for our understanding of the cosmos that scientists get a reliable grip on the North Star's true distance, emphasized Turner, whose study will appear in Astrophysical Journal Letters.
For instance, research on dark energy—the mysterious force thought to be causing the universe to fly apart faster over time—is dependent on stars such as the North Star.
Originally posted by MagicWand67
reply to post by XPLodER
Thanks for that explanation.
Originally posted by Phage
The claim of Turner et. al., that Polaris is 30% closer than indicated by the Hipparcos data is based on a different method of determining that distance. The article points out several clues that the Hipparcos calculations should have been suspect all along. It also points out that other, earlier (from the 1950s and 60s) calculations showed the distance to Polaris as being in agreement with theirs. Basically they are saying that the astronomers who determined the distance to Polaris from the Hipparcos data screwed up and probably should have realized it.
I'm sure this article will create a very lively discussion in the world of astrophysics but it doesn't really upset any apple carts concerning the distance other objects. It is about Polaris and Polaris alone and they haven't really figured that star out.
arxiv.org...
edit on 12/17/2012 by Phage because: (no reason given)
Your understanding is wrong. Polaris is not used as a measuring stick.
i had the understanding that polarus was used (closest to us) as an indicator of distance, this info was then used as a "standard candle" of sorts that equated all subsequent cephids to these measurements,
Originally posted by Phage
reply to post by XPLodER
Your understanding is wrong. Polaris is not used as a measuring stick.
i had the understanding that polarus was used (closest to us) as an indicator of distance, this info was then used as a "standard candle" of sorts that equated all subsequent cephids to these measurements,
The use of Cephid variables in determining distance is based on the discovery that for a given period of variability the star will have a given luminosity. By knowing the luminosity of the star, its distance can be determined (the farther away it is the less its apparent brightness, a direct calculation).
This article has refined the "typing" of Polaris and used that to determine its luminosity. It is from that luminosity that its distance was calculated.