USNO: Astronomers Measure New Distances to Nearby Stars

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USNO: Astronomers Measure New Distances to Nearby Stars

Post by bystander » Thu Oct 05, 2017 3:20 pm

Astronomers Measure New Distances to Nearby Stars
US Naval Observatory | 2017 Oct 04

Astronomers from the U.S. Naval Observatory (USNO), in collaboration with others from the REsearch Consortium On Nearby Stars (RECONS), have determined new distances to a group of faint young stars located within 25 parsecs (pc) of the Sun. These measurements, based on parallax observations obtained over periods ranging from nine to twelve years, include new measures of the star known as TRAPPIST-1, which has been recently identified as having a system of up to seven Earth-sized planets orbiting around it. ...

Measuring the distances to nearby stars is accomplished by a technique called “trigonometric parallax,” in which the tiny apparent annual shift of a star’s position is related to the diameter of the Earth’s orbit around the Sun. By measuring the tiny angle produced by this motion, astronomers can use trigonometry to determine the distance to the star. The distances to these stars are measured in parsecs, short for “parallax second.” One parsec is the distance at which a star would show an annual parallax shift of one second of arc on the plane of the sky; it is equivalent to 3.26 light-years.

Utilizing the 0.9-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile, Dr. Bartlett and her colleagues measured the parallaxes of 32 stellar systems, most of which are very cool faint red dwarf stars. Of these systems, 17 have never had previous parallax measurements, and out of those, 14 have been found to lie less than 25 pc from the Earth. One of these new, nearby stars, 2MASS 2351-2537AB, also shows evidence of actually being two new nearby stars, i.e., a binary. ...

The Solar Neighborhood. XXXX. Parallax Results from the CTIOPI 0.9 m Program: New Young Stars Near the Sun - Jennifer L. Bartlett et al
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