Gliese 667
Gliese 667 (142 G. Scorpii) is a triple-star system in the constellation of Scorpius lying at a distance of about 6.8 pc (23.6 ly) from Earth. All three of the stars have masses smaller than the Sun. There is a 12th magnitude star close to the other three, but it is not gravitationally bound to the system. To the naked eye, the system appears to be a single faint star of magnitude 5.89.
The system has a relatively high proper motion, exceeding 1 second of arc per year.
Star system
The two brightest stars in this system, GJ 667 A and GJ 667 B, are orbiting each other at an average angular separation of 1.81 arcseconds with a high eccentricity of 0.58. At the estimated distance of this system, this is equivalent to a physical separation of about 12.6 AU, or nearly 13 times the separation of the Earth from the Sun. Their eccentric orbit brings the pair as close as about 5 AU to each other, or as distant as 20 AU, corresponding to an eccentricity of 0.6. This orbit takes approximately 42.15 years to complete and the orbital plane is inclined at an angle of 128° to the line of sight from the Earth. The third star, GJ 667 C, orbits the GJ 667 AB pair at an angular separation of about 30", which equates to a minimum separation of 230 AU.
HD 147513
HD 147513 (62 G. Scorpii) is a star in the southern constellation of Scorpius. It was first catalogued by Italian astronomer Piazzi in his star catalogue as "XVI 55". With an apparent magnitude of 5.38, according to the Bortle scale it is visible to the naked eye from suburban skies. Based upon stellar parallax measurements by the Hipparcos spacecraft, HD 147513 lies some 42 light years from the Sun.
Properties
This is a Sun-like main sequence star with a stellar classification of G1VH-04. It has about 11% greater mass than the Sun, and is considered young with an estimated age of 400 million years. As such, it has a similar luminosity to the Sun despite being more massive. Although the abundance of elements is similar to the Sun, it is a Barium star that is overabundant in elements produced through the s-process. HD 147513 is suspected of being a variable star.
HD 147513 is a member of the Ursa Major moving group that share a common proper motion through space. It has a nearby co-moving companion: a DA-class white dwarf located some 5,360 AU distant, where an AU is the average separation of the Earth from the Sun. At one time the pair may have been members of a multiple star system. The progenitor of the white dwarf may have been a closer companion, and while passing through the asymptotic giant branch stage of its evolution, could have transferred matter onto HD 147513 and contaminated this star's photosphere.
G Scorpii
G Scorpii (G Sco) is a star in the constellation Scorpius. It is an orange K-type giant with an apparent magnitude of +3.19. It is approximately 126 light years from Earth. The measured angular diameter of the primary star is 3.94 ± 0.21 mas. At the estimated distance of this system, this yields a physical size of about 16 times the radius of the Sun.
Just 8.5 arcminutes to the east is the globular cluster NGC 6441.
It was formerly known as "Gamma Telescopii" (γ Tel) and "Fuyue" （傅說） in ancient China.
See also
References
Podcasts:
