VW Leo Minoris is a tight quadruple[6] star system, located in the constellation of Leo Minor. With a peak combined apparent visual magnitude of 8.07,[3] it is too faint to be seen with the naked eye. Parallax measurements give a distance estimate of approximately 370 light years from the Sun, and it is drifting further away with a radial velocity of +5 km/s.[3]

VW Leonis Minoris

A light curve VW Leonis Minoris, plotted from TESS data[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Leo Minor
Right ascension	11h 02m 51.910s[2]
Declination	30° 24′ 54.70″[2]
Apparent magnitude (V)	8.07[3]
Characteristics
Spectral type	F2V + G2V[4]
B−V color index	+0.410±0.015[3]
Variable type	Suspected W UMa[5]
Astrometry
Radial velocity (Rv)	+5.00±0.75[3] km/s
Proper motion (μ)	RA: +12.304 mas/yr[2] Dec.: −4.764 mas/yr[2]
Parallax (π)	8.8238 ± 0.1046 mas[2]
Distance	370 ± 4 ly (113 ± 1 pc)
Absolute magnitude (MV)	2.46[3]
Orbit – Contact (1 & 2)[6]
Period (P)	11.461225 h
Eccentricity (e)	0.0
Semi-amplitude (K1) (primary)	105.8±1.0 km/s
Semi-amplitude (K2) (secondary)	250.2±1.2 km/s
Orbit – Non-contact (3 & 4)[6]
Period (P)	7.93063 d
Eccentricity (e)	0.035±0.003
Periastron epoch (T)	2,452,274.54±0.11 HJD
Argument of periastron (ω) (secondary)	1.90±0.09°
Semi-amplitude (K1) (primary)	63.99±0.23 km/s
Semi-amplitude (K2) (secondary)	65.53±0.27 km/s
Orbit – Mutual (12 & 34)[6]
Period (P)	355.02±0.17 d
Eccentricity (e)	0.097±0.011
Periastron epoch (T)	2,453,046±6 HJD
Argument of periastron (ω) (secondary)	2.20±0.12°
Semi-amplitude (K1) (primary)	21.61±0.49 km/s
Semi-amplitude (K2) (secondary)	23.22±0.33 km/s
Details
Component 1
Mass	1.68±0.02[7] M☉
Radius	1.69±0.02[7] R☉
Luminosity	8.73[3] L☉
Surface gravity (log g)	4.21±0.02[7] cgs
Component 2
Mass	0.71±0.02[7] M☉
Radius	1.18±0.02[7] R☉
Surface gravity (log g)	4.14±0.02[7] cgs
Other designations
VW LMi, BD+31°2225, HD 95660, HIP 54003, SAO 62372[8]
Database references
SIMBAD	data

This system was found to be variable using observations with the Hipparcos satellite. It is classified as an A-type[7] W Ursae Majoris eclipsing binary, where the two stars share a common envelope. The eclipse of the primary causes the magnitude of the system to drop to 8.45.[5] These components (1 & 2) have an orbital period of 11.4611 hours and the orbital plane has an inclination of 72.4° to the line of sight from the Earth.[6] They have a combined stellar classification of F2V, matching an F-type main sequence star.[4]

In 2006 an additional, detached binary component was discovered, making this a quadruple star system.[9] This binary has an orbital period of 7.93 days, a mild eccentricity (ovalness) of 0.04,[6] and it shows an apsidal precession with a period of 78.6±1.6 years.[4] The components (3 & 4) have a combined stellar class of G2V,[4] showing a match with a G-type main-sequence star.[4]

The two binaries (1–2 & 3–4) orbit each other with a period of 355 days and an eccentricity of 0.1.[6] The plane of their orbit is close to coplanar (within 5°) with the orbital plane of the detached binary. This outer orbit appears stable, suggesting there is no additional outlying component to this system.[4] The nearby ninth magnitude star HD 95606 (HIP 53969) shares a common proper motion with this system and may be loosely gravitationally bound. They likely all formed in the same protostellar cloud.[6]

References