Alpha Vulpeculae


Alpha Vulpeculae, officially named Anser, is the brightest star in the constellation of Vulpecula. It is approximately 297 light-years from Earth. It forms a wide optical binary with 8 Vulpeculae.
Alpha Vulpeculae is a red giant of spectral class M1 and has apparent magnitude +4.4. It has been analysed as a member of the Arcturus stream, a group of stars with high proper motion and metal-poor properties thought to be the remnants of a small galaxy consumed by the Milky Way.

Nomenclature

α Vulpeculae is the system's Bayer designation.
It bore the traditional name Anser, derived from when the constellation had the name Vulpecula cum Ansere 'the little fox with the goose'. In 2016, the IAU organized a Working Group on Star Names to catalog and standardize proper names for stars. The WGSN approved the name Anser for this star on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.

Description

α Vulpeculae has evolved away from the main sequence after exhausting its core hydrogen and is now a red giant, probably on the red giant branch. It is about 11.3 billion years since it first formed. It has an effective surface temperature of and a bolometric luminosity of, meaning that its radius is.
α Vulpeculae has been suspected to be variable in brightness by about a tenth of a magnitude, but this has never been confirmed. Analysis of the isotopic ratios in its photosphere show that it has a mass less than and has not yet evolved to the asymptotic giant branch and experienced a third dredge up.