Astrophysics (Index)About

stellar distance determination

(methods by which the distance to a star is determined)

Stellar distance determination uses the shorter cosmic distance ladder methods, i.e., within the Milky Way. Parallax is the certain method up to the angular resolution accuracy of astrometry. Optical observations from opposite ends of Earth's orbit are used to determine the triangle from those two points to the observed star. This continues to improve with improvements in angular resolution and astrometry, and with current space astrometry (Gaia), provides useful data at thousands of parsecs.

When stellar luminosity determination produces a reasonable estimate, its luminosity distance provides a corresponding distant estimate. Spectroscopic parallax bases this on the typical luminosity of specific spectral types. (Despite its word "parallax", it is like parallax only in that it is a means of measuring distance.) Binary stars, depending upon the circumstance, may reveal mass and radius information, providing clues. Certain types of stars such as Cepheid variables provide luminosity information, through characteristics of pulses and/or spectral signatures. Given one or more stellar distance determinations of stars within a stellar cluster, it serves as a rough determination of distances to the rest of the cluster's stars. An estimate of the luminosity of cluster members can also make use of the group's characteristics, through main sequence fitting.


(stars,astrophysics,distance)
Further reading:
https://en.wikipedia.org/wiki/Cosmic_distance_ladder
https://en.wikipedia.org/wiki/Stellar_parallax
https://en.wikipedia.org/wiki/Spectroscopic_parallax
http://www.ast.cam.ac.uk/~mjp/
http://www.astro.ucla.edu/~wright/distance.htm

Referenced by pages:
Gliese-Jahreiss Catalog (GJ)
kinematic distance
main sequence fitting
stellar luminosity determination
stellar parameter determination
Wilson-Bappu effect

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