Stein 2051
Star in the constellation Camelopardalis
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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.[18]
Annotated Hubble Space Telescope image of the Stein 2051 components and a background star ("source") used to measure the bending of starlight Credit: NASA, ESA, and K. Sahu (STScI) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Camelopardalis[1] |
| Stein 2051 A | |
| Right ascension | 04h 31m 11.5144s[2] |
| Declination | +58° 58′ 37.464″[2] |
| Apparent magnitude (V) | 10.98[3] |
| Stein 2051 B | |
| Right ascension | 04h 31m 12.5714s[4] |
| Declination | +58° 58′ 41.293″[4] |
| Apparent magnitude (V) | 12.43[5] |
| Characteristics | |
| Stein 2051 A | |
| Evolutionary stage | main sequence[6] |
| Spectral type | M4.0Ve[7] |
| U−B color index | +1.21[8] |
| B−V color index | +1.65[8] |
| Stein 2051 B | |
| Evolutionary stage | white dwarf[9] |
| Spectral type | DC5[10] |
| U−B color index | -0.53[8] |
| B−V color index | +0.31[8] |
| Astrometry | |
| Stein 2051 A | |
| Radial velocity (Rv) | +29[11] km/s |
| Proper motion (μ) | RA: +1,300.365 mas/yr[2] Dec.: −2,046.106 mas/yr[2] |
| Parallax (π) | 181.2438±0.0499 mas[2] |
| Distance | 17.995 ± 0.005 ly (5.517 ± 0.002 pc) |
| Absolute magnitude (MV) | +12.36[12] |
| Stein 2051 B | |
| Radial velocity (Rv) | +2.0[13] km/s |
| Proper motion (μ) | RA: +1,334.780±0.021[4] mas/yr Dec.: −1,947.638±0.019[4] mas/yr |
| Parallax (π) | 181.2730±0.0203 mas[4] |
| Distance | 17.993 ± 0.002 ly (5.5165 ± 0.0006 pc) |
| Absolute magnitude (MV) | +13.71[14] |
| Details[6] | |
| Stein 2051 A | |
| Mass | 0.252±0.013[15] M☉ |
| Radius | 0.292±0.031[15] R☉ |
| Luminosity | 0.0081[15] 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 |
| Age | 1.9 - 3.6 [9] Gyr |
| Stein 2051 B | |
| Mass | 0.675±0.051[9] M☉ |
| Radius | 0.0114±0.0004[9] R☉ |
| Luminosity | 0.00003[a] L☉ |
| Surface gravity (log g) | 8.153[b] cgs |
| Temperature | 7122±181[9] K |
| Age | 1.9±0.4 (cooling age)[9] Gyr |
| Other designations | |
| Stein 2051, G 175-34, HIP 21088,[16] WDS J04312+5858AB, GJ 169.1,[17] PLX 986.01[18] | |
| Stein 2051 A: LHS 26, NLTT 13373, TYC 3744-412-1, 2MASS J04311147+585837, WISE J043113.20+585816.7[19] | |
| 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[20] | |
| Database references | |
| SIMBAD | A |
| B | |
  Stein 2051 Location of Stein 2051 in the constellation Camelopardalis | |
Stein 2051 is the nearest (red dwarf + white dwarf) separate binary system (40 Eridani BC is located closer at 16.26 light-years,[21] 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.[9]