Atlas (star)
Template:Short description Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox orbit Template:Starbox detail Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end
Atlas Template:IPAc-en,<ref name=Kunitzsch>Template:Cite book</ref> designation 27 Tauri, is a triple star system in the constellation of Taurus. It is a member of the Pleiades, an open star cluster (M45). It is 431 light-years (132 parsecs) away,<ref name=Zwahlen/> and is 3.92 degrees north of the ecliptic.
NomenclatureEdit
27 Tauri is the star's Flamsteed designation.
In 2016 the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> to catalogue and standardize proper names for stars. The WGSN approved the name Atlas for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.<ref name="IAU-CSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
MythologyEdit
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Atlas was a Titan and the father of the Pleiades sisters in Greek mythology.
PropertiesEdit
Atlas is a triple star system, with the inner pair orbiting in under a year and the outer star orbiting in 260 years. The outer star, component Ab (sometimes component B, such as in CCDM and SIMBAD<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>), has been resolved at a distance of Template:Val from the unresolved spectroscopic binary. It is too close to have been assigned a spectral class, but has an apparent magnitude of 6.8, three magnitudes fainter than the combined magnitude of the closer pair. Its mass is estimate to be twice that of the Sun. In the WDS catalog, there are 8 other stars, ranging from B-I, which have been classed as companions of Atlas.<ref name="msc">Template:Cite journal</ref>
The inner pair have a well-defined orbit with a period of 291 days, a semi-major axis of Template:Val, and an eccentricity of 0.24. At an inclination of 108°, it is not thought to show eclipses.<ref name=Zwahlen/> Although the two stars cannot be resolved, the primary, component Aa1, is calculated to be 1.6 magnitudes brighter than the secondary, component Aa2.<ref name=msc/>
Low amplitude variability of the brightness of Atlas was tentatively detected in observations by STEREO and clearly detected by Kepler/K2. The light curve varies with several periods, the most prominent being 2.427, 0.7457 and 1.214 days.<ref name="WhiteMNRAS471"/> Template:Clear left