Stein 2051

Observation data Epoch J2000 Equinox J2000

ConstellationCamelopardalis

Stein 2051 A

Right ascension04h 31m 11.5144s

Declination+58° 58′ 37.464″

Apparent magnitude (V)10.98

Stein 2051 B

Right ascension04h 31m 12.5714s

Declination+58° 58′ 41.293″

Apparent magnitude (V)12.43

Characteristics

Stein 2051 A

Evolutionary stagemain sequence

Spectral typeM4.0Ve

U−B color index+1.21

B−V color index+1.65

Stein 2051 B

Evolutionary stagewhite dwarf

Spectral typeDC5

U−B color index-0.53

B−V color index+0.31

Astrometry

Stein 2051 A

Radial velocity (R v )+29km/s

Proper motion (μ)RA: +1,300.365mas/yr Dec.: −2,046.106mas/yr

Parallax (π)181.2438±0.0499 mas

Distance17.995 ± 0.005 ly (5.517 ± 0.002 pc)

Absolute magnitude (M V )+12.36

Stein 2051 B

Radial velocity (R v )+2.0km/s

Proper motion (μ)RA: +1,334.780±0.021mas/yr Dec.: −1,947.638±0.019mas/yr

Parallax (π)181.2730±0.0203 mas

Distance17.993 ± 0.002 ly (5.5165 ± 0.0006 pc)

Absolute magnitude (M V )+13.71

Details

Stein 2051 A

Mass0.252±0.013 M☉

Radius0.292±0.031 R☉

Luminosity0.0081 L☉

Surface gravity (log g )4.80+0.13 −0.10 cgs

Temperature3277+42 −75 K

Metallicity [Fe/H]0.26+0.06 −0.22 dex

Rotational velocity ( v sin i )5.2+1.7 −2.7 km/s

Age1.9 - 3.6 Gyr

Stein 2051 B

Mass0.675±0.051 M☉

Radius0.0114±0.0004 R☉

Luminosity0.00003 L☉

Surface gravity (log g )8.153 cgs

Temperature7122±181 K

Age1.9±0.4 (cooling age) Gyr

Other designations

Stein 2051, G 175-34, HIP 21088, WDS J04312+5858AB, GJ 169.1, PLX 986.01

Stein 2051 A: LHS 26, NLTT 13373, TYC 3744-412-1, 2MASS J04311147+585837, WISE J043113.20+585816.7

Stein 2051 B: EGGR 180, LHS 27, NLTT 13375, TYC 3744-2062-1, 2MASS J04311201+5858476, WD 0426+58, WD2 0426+585, WD3 0426+588

Database references

SIMBAD

Stein 2051 (Gliese 169.1, G 175-034, LHS 26/27) is a nearby binary star system, containing a red dwarf (component A) and a degenerate star (white dwarf) (component B), located in constellation Camelopardalis at about 18 ly from Earth.

Stein 2051 is the nearest (red dwarf + white dwarf) separate binary system (40 Eridani BC is located closer at 16.26 light-years, but it is a part of a triple star system).

Stein 2051 B is the 6th nearest white dwarf after Sirius B, Procyon B, van Maanen's star, LP 145-141 and 40 Eridani B.

Properties

The brighter of these two stars is A (a red dwarf), but the more massive is component B (a white dwarf).

In 2017, Stein 2051 B was observed passing in front of a more distant star. The bending of starlight by the gravitational field of the nearer star allowed its mass to be directly measured. The estimated mass of Stein 2051 B is 0.675±0.051 M☉, which fits the expected range of a white dwarf with a carbon-oxygen core.

Notes

External links

. Centre de Données astronomiques de Strasbourg. (the whole system)
. Centre de Données astronomiques de Strasbourg. (component A)
. Centre de Données astronomiques de Strasbourg. (component B)