V538 Aurigae

V538 Aurigae

A light curve for V538 Aurigae, plotted from TESS data. The data was folded with the period of 10.86 days which was published by Gaidos et al. (2000).
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension 05h 41m 20.33573s
Declination +53° 28 51.8106
Apparent magnitude (V) 6.25
Characteristics
Evolutionary stage Main sequence
Spectral type K1 V
U−B color index 0.50
B−V color index 0.84
Variable type BY Dra
Astrometry
Radial velocity (Rv)0.9 km/s
Proper motion (μ) RA: +2.784 mas/yr
Dec.: −523.602 mas/yr
Parallax (π)81.4300±0.0487 mas
Distance40.05 ± 0.02 ly
(12.280 ± 0.007 pc)
Absolute magnitude (MV)5.75
Details
Mass0.871 M
Radius0.82+0.02
−0.03
 R
Luminosity0.478±0.001 L
Surface gravity (log g)4.55 cgs
Temperature5,303+100
−63
 K
Metallicity [Fe/H]+0.16 dex
Rotation11 days
Rotational velocity (v sin i)2.80 km/s
Age3.76 Gyr
Other designations
V538 Aur, BD+53°934, GJ 211, HD 37394, HIP 26779, HR 1925, WDS J05413+5329A
Database references
SIMBADdata

V538 Aurigae is a single star in the northern constellation of Auriga. With an apparent visual magnitude of 6.23, this star requires good dark sky conditions to view with the naked eye. It is located at a distance of 40.0 light-years (12.3 pc) from Sun based on parallax. The star is drifting further away with a radial velocity of 0.9 km/s. It is a member of the Local Association, and is most likely a thin disk star.

Eric Gaidos et al. discovered that V538 Aurigae is a variable star based on observations by robotic telescopes at Fairborn Observatory from 1993 through 1999, and they announced their discovery in 2000. The star was given its variable star designation in 2006. This is a BY Draconis variable, which means it undergoes changes in luminosity because regions of pronounced surface magnetic activity are moved into and out of the line of sight from the Earth as the star rotates (once every 11 days). It has a spectral class of K1 V, indicating that it is a K-type main sequence star. The star has 87% of the mass of the Sun and 82% of the Sun's radius. It is an estimated 3.76 billion years old. The star is radiating 48% of the Sun's luminosity from its photosphere at an effective temperature of 5,303 K.

It has a common proper motion companion designated Vys 465 (HD 233153), which is a red dwarf with a class of M0.5V and a visual magnitude of 9.87. Their projected separation is 1,204 AU.