Gliese 223.2
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Coordinates: 
05h 55m 09.53s, −04° 10′ 07.1″
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Orion |
| Right ascension | 05h 55m 09.53s[1] |
| Declination | −04° 10′ 07.1″[1] |
| Apparent magnitude (V) | 14.488[2] |
| Characteristics | |
| Spectral type | DZ11.8[2] |
| Apparent magnitude (B) | 15.49[1] |
| Apparent magnitude (V) | 14.488[2] |
| Apparent magnitude (RKC) | 13.99[3] |
| Apparent magnitude (IKC) | 13.51[3] |
| Apparent magnitude (J) | 13.05 ± 0.03[3] |
| Apparent magnitude (H) | 12.86 ± 0.03[3] |
| Apparent magnitude (KS) | 12.78 ± 0.03[3] |
| B−V color index | 1.0[1][2] |
| Astrometry | |
| Proper motion (μ) | RA: 551[3] mas/yr Dec.: −2311[3] mas/yr |
| Parallax (π) | 156.13 ± 0.84[3] mas |
| Distance | 20.9 ± 0.1 ly (6.40 ± 0.03 pc) |
| Absolute magnitude (MV) | 15.44 ± 0.03[3] |
| Details | |
| Mass | 0.45 ± 0.01,[2] or 0.80 ± 0.01[3] M☉ |
| Radius | 0.014,[2][note 1] or 0.010[3] R☉ |
| Surface gravity (log g) | 7.80 ± 0.02,[2] or 8.35 ± 0.01[3] |
| Temperature | 4270 ± 70,[2] or 5180 ± 70[3] K |
| Age | 6.42,[4] or 6.82 ± 0.02[3][note 2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Gliese 223.2 (GJ 9193) is a degenerate (white dwarf) star in the constellation of Orion,[1] the single known object in its system. It has an apparent visual magnitude of approximately 14.488.[2]
Contents |
Distance [edit]
According to a 2009 paper, it is the eighth closest known white dwarf to the Sun (after Sirius B, Procyon B, van Maanen's star, Gliese 440, 40 Eridani B, Stein 2051 B and GJ 1221).[6] Its trigonometric parallax from the CTIOPI (Cerro Tololo Inter-American Observatory (CTIO) Parallax Investigation) 0.9 m telescope program, published in 2009, is 0.15613 ± 0.00084 arcsec,[3] corresponding to a distance 6.40 ± 0.03 pc, or 20.89 ± 0.11 ly. Also, previous less precise parallax measurements of Gliese 223.2 present in YPC (Yale Parallax Catalog) and among results of CTIOPI 1.5 m telescope program:
Gliese 223.2 parallax measurements
| Source | Paper | Parallax, mas | Distance, pc | Distance, ly | Ref. |
|---|---|---|---|---|---|
| YPC | van Altena et al., 1995 | 155.0 ± 2.1 | 6.45 ± 0.09 | 21.04 ± 0.29 | [5] |
| CTIOPI 1.5 m | TSN-14 (Costa et al., 2005) | 156.93 ± 2.67 | 6.37 ± 0.11 | 20.78 ± 0.35 | [7] |
| CTIOPI 0.9 m | TSN-21 (Subasavage et al., 2009) | 156.13 ± 0.84 | 6.40 ± 0.03 | 20.89 ± 0.11 | [3] |
Physical parameters [edit]
There are two sets of published physical parameters of Gliese 223.2, significantly differing from each other: from Holberg et al. 2008, April[2] / Sion et al. 2009, December[4] articles, and from Subasavage et al. 2009, June[3] article:
Holberg et al. 2008 / Sion et al. 2009 version [edit]
- Mass: 0.45 ± 0.01 Solar masses
- Surface gravity: 107.80 ± 0.02 (6.31 · 107) cm·s−2, or approximately 64 000 of Earth's
- Radius: 9771 km, or 153% of Earth's[note 1]
- Temperature: 4270 ± 70 K
- Age: 6.42 Gyr[4][note 2]
Subasavage et al. 2009 version [edit]
- Mass: 0.80 ± 0.01 Solar masses
- Surface gravity: 108.35 ± 0.01 (2.24 · 108) cm·s−2, or approximately 228 000 of Earth's
- Radius: 6916 km, or 109% of Earth's[note 1]
- Temperature: 5180 ± 70 K
- Age: 6.82 ± 0.02 Gyr[note 2]
Color [edit]
Despite it is classified as "white dwarf", it should appear orange, not white, due low temperature, comparable with that of late (according Holberg et al. 2008 / Sion et al. 2009 version), or early (according Subasavage et al. 2009 version) K-type main sequence stars.
Notes [edit]
- ^ a b c From surface gravity and mass.
- ^ a b c White dwarf cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star)
References [edit]
- ^ a b c d e f NAME HL 4 -- White Dwarf, database entry, SIMBAD. Accessed on line January 17, 2011.
- ^ a b c d e f g h i j Holberg, J. B.; Sion; Oswalt; McCook; Foran; Subasavage (2008). "A NEW LOOK AT THE LOCAL WHITE DWARF POPULATION". The Astronomical Journal 135: 1225–1238. Bibcode:2008AJ....135.1225H. doi:10.1088/0004-6256/135/4/1225.
- ^ a b c d e f g h i j k l m n o p q Subasavage, John P.; Jao; Henry; Bergeron; Dufour; Ianna; Costa; Mendez (2009). "THE SOLAR NEIGHBORHOOD. XXI. PARALLAX RESULTS FROM THE CTIOPI 0.9 m PROGRAM: 20 NEW MEMBERS OF THE 25 PARSEC WHITE DWARF SAMPLE". The Astronomical Journal 137: 4547–4560. Bibcode:2009AJ....134.4547S. doi:10.1088/0004-6256/137/6/4547.
- ^ a b c Sion, Edward M.; Holberg; Oswalt; McCook; Wasatonic (2009). "THE WHITE DWARFS WITHIN 20 PARSECS OF THE SUN: KINEMATICS AND STATISTICS". The Astronomical Journal 138: 1681–1689. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681.
- ^ a b Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
- ^ Table 1, "The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics", Edward M. Sion et al., The Astronomical Journal 138, #6 (December 2009), pp. 1681-1689, doi:10.1088/0004-6256/138/6/1681, Bibcode: 2009AJ....138.1681S.
- ^ Costa, Edgardo; Mendez; Jao; Henry; Subasavage; Brown; Ianna; Bartlett (2005). "THE SOLAR NEIGHBORHOOD. XIV. PARALLAXES FROM THE CERRO TOLOLO INTER-AMERICAN OBSERVATORY PARALLAX INVESTIGATION—FIRST RESULTS FROM THE 1.5 m TELESCOPE PROGRAM". The Astronomical Journal 130: 337–349. Bibcode:2005AJ....130..337C. doi:10.1086/430473.
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