HD 139691
Encyclopedia
HD
139691 is a star system that consists of six stars. Four of the stars are visually separate in the sky, forming a visual star system, which was resolved using adaptive optics
in 1995. Two of these stars were themselves found to be spectroscopic binaries in 1998, resulting in a total of six known stars in the system.
The combined light from the whole system results in an integrated V magnitude of 6.9. The parallax
measured by the Hipparcos
satellite indicates that the system is relatively nearby at around 110 pc from the Sun. However, this distance is highly uncertain because the multiple stars in the system prevented Hipparcos from accurately measuring the parallax; the system may instead be at a distance of about 200 pc.
The star system has been considered as a possible target for direct imaging searches for exoplanets, but no planets have yet been detected in the system.
Henry Draper Catalogue
The Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...
139691 is a star system that consists of six stars. Four of the stars are visually separate in the sky, forming a visual star system, which was resolved using adaptive optics
Adaptive optics
Adaptive optics is a technology used to improve the performance of optical systems by reducing the effect of wavefront distortions. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, and in retinal imaging systems to reduce the...
in 1995. Two of these stars were themselves found to be spectroscopic binaries in 1998, resulting in a total of six known stars in the system.
The combined light from the whole system results in an integrated V magnitude of 6.9. The parallax
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
measured by the Hipparcos
Hipparcos
Hipparcos was a scientific mission of the European Space Agency , launched in 1989 and operated between 1989 and 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky...
satellite indicates that the system is relatively nearby at around 110 pc from the Sun. However, this distance is highly uncertain because the multiple stars in the system prevented Hipparcos from accurately measuring the parallax; the system may instead be at a distance of about 200 pc.
The star system has been considered as a possible target for direct imaging searches for exoplanets, but no planets have yet been detected in the system.