![]() Image of Stein 2051 B and a background star taken by the Hubble Space Telescope. [1] Credit: NASA, ESA, and K. Sahu (STScI) | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Camelopardalis [2] |
Stein 2051 A | |
Right ascension | 04h 31m 11.5144s [3] |
Declination | +58° 58′ 37.464″ [3] |
Apparent magnitude (V) | 10.98 [4] |
Stein 2051 B | |
Right ascension | 04h 31m 12.5714s [5] |
Declination | +58° 58′ 41.293″ [5] |
Apparent magnitude (V) | 12.43 [6] |
Characteristics | |
Stein 2051 A | |
Evolutionary stage | main sequence [7] |
Spectral type | M4.0Ve [8] |
U−B color index | +1.21 [9] |
B−V color index | +1.65 [9] |
Stein 2051 B | |
Evolutionary stage | white dwarf [10] |
Spectral type | DC5 [11] |
U−B color index | -0.53 [9] |
B−V color index | +0.31 [9] |
Astrometry | |
Stein 2051 A | |
Radial velocity (Rv) | 29 [12] km/s |
Proper motion (μ) | RA: 1300.365 mas/yr [3] Dec.: -2046.106 mas/yr [3] |
Parallax (π) | 181.2438±0.0499 mas [3] |
Distance | 17.995 ± 0.005 ly (5.517 ± 0.002 pc) |
Absolute magnitude (MV) | +12.36 [13] |
Stein 2051 B | |
Radial velocity (Rv) | 2.0 [14] km/s |
Proper motion (μ) | RA: 1334.780±0.021 [5] mas/yr Dec.: −1947.638±0.019 [5] mas/yr |
Parallax (π) | 181.2730 ± 0.0203 mas [5] |
Distance | 17.993 ± 0.002 ly (5.5165 ± 0.0006 pc) |
Absolute magnitude (MV) | +13.71 [15] |
Details [7] | |
Stein 2051 A | |
Mass | 0.252±0.013 [16] M☉ |
Radius | 0.292±0.031 [16] R☉ |
Luminosity | 0.0081 [16] L☉ |
Surface gravity (log g) | 4.80+0.13 −0.10 cgs |
Temperature | 3277+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 |
Stein 2051 B | |
Mass | 0.675±0.051 [10] M☉ |
Radius | 0.0114±0.0004 [10] R☉ |
Temperature | 7122±181 [10] K |
Other designations | |
Stein 2051, G 175-34, HIP 21088, [17] WDS J04312+5858AB, GJ 169.1, [18] PLX 986.01 [19] | |
Stein 2051 A: LHS 26, NLTT 13373, TYC 3744-412-1, 2MASS J04311147+585837, WISE J043113.20+585816.7 [20] | |
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 [21] | |
Database references | |
SIMBAD | A |
B | |
Location of Stein 2051 in the constellation Camelopardalis |
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. [19]
Stein 2051 is the nearest (red dwarf + white dwarf) separate binary system (40 Eridani BC is located closer at 16.26 light-years, [22] 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.
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. [10]