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Astronomy Picture of the Day -- Nearby Cepheid Variable RS Pup
NASA ^ | September 09, 2013 | (see photo credit)

Posted on 09/09/2013 7:42:32 PM PDT by SunkenCiv

Explanation: It is one of the most important stars in the sky. This is partly because, by coincidence, it is surrounded by a dazzling reflection nebula. Pulsating RS Puppis, the brightest star in the image center, is some ten times more massive than our Sun and on average 15,000 times more luminous. In fact, RS Pup is a Cepheid type variable star, a class of stars whose brightness is used to estimate distances to nearby galaxies as one of the first steps in establishing the cosmic distance scale. As RS Pup pulsates over a period of about 40 days, its regular changes in brightness are also seen along the nebula delayed in time, effectively a light echo. Using measurements of the time delay and angular size of the nebula, the known speed of light allows astronomers to geometrically determine the distance to RS Pup to be 6,500 light-years, with a remarkably small error of plus or minus 90 light-years. An impressive achievement for stellar astronomy, the echo-measured distance also more accurately establishes the true brightness of RS Pup, and by extension other Cepheid stars, improving the knowledge of distances to galaxies beyond the Milky Way. The above image was taken by the Hubble Space Telescope and digitally processed by a volunteer.

September 09, 2013

(Excerpt) Read more at 129.164.179.22 ...


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; astronomy; cepheidvariable; science
[Credit: Hubble Legacy Archive, NASA, ESA; Processing: Stephen Byrne]

1 posted on 09/09/2013 7:42:32 PM PDT by SunkenCiv
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To: brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; steelyourfaith; Mmogamer; ...

Star Party? List it here.
The Big One

2 posted on 09/09/2013 7:42:58 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: SunkenCiv

LIKE!!!!


3 posted on 09/09/2013 7:55:10 PM PDT by left that other site (You Shall Know the Truth, and the Truth Shall Set You Free...John 8:32)
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To: SunkenCiv

and someone would say that there is no God.........pathetic


4 posted on 09/09/2013 9:05:36 PM PDT by terycarl
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