HD 150136 is a multiple star system in the southern constellation of

Ara ARA may refer to: Media and the arts * American-Romanian Academy of Arts and Sciences * '' Artistička Radna Akcija'', compilation album released in former Yugoslavia * Associate of the Royal Academy, denoting membership in the British Royal Aca ...

, around 4,300 light years away. It is the brightest member of the faint

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, an ...

NGC 6193 NGC 6193 (also known as Caldwell 82) is open cluster containing 27 stars in the constellation Ara ARA may refer to: Media and the arts * American-Romanian Academy of Arts and Sciences * '' Artistička Radna Akcija'', compilation album release ...

, part of the Ara OB1

association Association may refer to: *Club (organization), an association of two or more people united by a common interest or goal *Trade association, an organization founded and funded by businesses that operate in a specific industry *Voluntary associatio ...

System

HD 150136 is listed in the

Washington Double Star Catalog The Washington Double Star Catalog, or WDS, is a catalog of double stars, maintained at the United States Naval Observatory. The catalog contains positions, magnitudes, proper motions and spectral types and has entries for (as of June 2017) 141, ...

as having seven visual components within . Component A is a close triple system containing three massive class O main sequence stars. The brightest companion is catalogued individually as HD 150135 as well as component C of the multiple system, separated by only 10 arcseconds. It is another O class spectroscopic binary and also a member of NGC 6193. The other catalogued components are all 10th to 12th magnitude, similar to many other stars known to be members of

. The primary star consists of a double-lined spectroscopic binary with a more distant tertiary companion. The third star is orbiting the other two with a

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

of 8.2 years, an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.73, and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 108°. The close binary stars are separated by hardly more than their own diameters and orbit in less than 3 days, but the third is separated enough to have been resolved visually by

VLTI The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across ...

. The measured separation in 2012 was 9 milli-arcseconds, corresponding to 11-12 AU.

Properties

All three (four, including HD 150135) of the brightest stars are massive luminous O class main sequence stars, 27 to 54 times as massive as the Sun. They are around 10 times the size of the Sun, but 6-8 times hotter and each is over 100,000 times as luminous. The primary star is the closest O3 star to Earth, , visually 18,000 times as bright as the sun, but because of its high temperature it is around three quarters of a million times more luminous including all wavelengths.

References

External links

*
HR 6187

Image HD 150136

CCDM J16413-4846
*

{{DEFAULTSORT:HD 150136 Ara (constellation) 150136 Triple star systems 6187 O-type main-sequence stars 081702 Durchmusterung objects Emission-line stars