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G 99-47

Summary

G 99-47 (V1201 Orionis) is a nearby degenerate star (white dwarf) of spectral class DAP8 (DAP8.9,[4] or DAP8.7[3]), the single known component of the system, located in the constellation Orion. G 99-47 is probably the tenth closest white dwarf, followed by Gliese 293, Gliese 518 and Gliese 915.

G 99-47

A visual band light curve for V1201 Orionis, adapted from Brinkworth et al. (2013)[1]
Observation data
Epoch J2000[2]      Equinox J2000[2]
Constellation Orion
Right ascension 05h 56m 25.47s[2]
Declination +05° 21′ 48.6″[2]
Apparent magnitude (V) 14.105[3]
Characteristics
Spectral type DAP8.9[4]
Apparent magnitude (B) 14.69[2]
Apparent magnitude (V) 14.10[2]
Apparent magnitude (R) 14.0[2]
Apparent magnitude (I) 13.6[2]
Apparent magnitude (J) 12.930 ± 0.022[2]
Apparent magnitude (H) 12.720 ± 0.025[2]
Apparent magnitude (K) 12.653 ± 0.024[2]
Astrometry
Proper motion (μ) RA: -444.685[5] mas/yr
Dec.: -925.140[5] mas/yr
Parallax (π)123.1989 ± 0.0170 mas[5]
Distance26.474 ± 0.004 ly
(8.117 ± 0.001 pc)
Absolute magnitude (MV)14.59[3][6][note 1]
Details
Mass0.71 ± 0.03[3] M☉
Radius0.011[3][note 2] R☉
Surface gravity (log g)8.20 ± 0.05[3] cgs
Temperature5790 ± 110[3] K
Age3.97[4][note 3] Gyr
Other designations
WD 0553+053,[3][4] V1201 Ori,[2] LHS 212,[3] LTT 17891,[2] NLTT 15834,[2] G 099-047,[6] GJ 1087,[2] G 102-40,[2] G 106-15,[2] EGGR 290,[2] 2MASS J05562547+0521486,[2] USNO-B1.0 0953-00073703, Gaia DR2 3320184202856027776[2]
Database references
SIMBADdata

The mass of G 99-47 is 0.71±0.03 Solar masses;[3] its surface gravity is 108.20 ± 0.05 (1.58 · 108) cm·s−2,[3] or approximately 162 000 of Earth's, corresponding to a radius 7711 km, or 121% of Earth's. Its temperature is 5790 ± 110 K,[3] almost like the Sun's; its cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star) is 3.97 Gyr.[4] Due almost equal to the Sun's temperature, GJ 1087 should appear almost the same white color as the Sun. The white dwarf has a strong magnetic field, with measured vertical component near surface equal to 560 T.[7]

See also edit

Notes edit

  1. ^ From apparent magnitude and parallax.
  2. ^ From surface gravity and mass.
  3. ^ White dwarf cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star)

References edit

  1. ^ Brinkworth, Carolyn S.; Burleigh, Matthew R.; Lawrie, Katherine; Marsh, Thomas R.; Knigge, Christian (August 2013). "Measuring the Rotational Periods of Isolated Magnetic White Dwarfs". The Astrophysical Journal. 773 (1): 47. Bibcode:2013ApJ...773...47B. doi:10.1088/0004-637X/773/1/47. hdl:2381/37593. S2CID 56285149.
  2. ^ a b c d e f g h i j k l m n o p q r s t "V* V1201 Ori -- White Dwarf". Centre de Données astronomiques de Strasbourg. Retrieved 2011-11-01.
  3. ^ a b c d e f g h i j k l Holberg, J. B.; Sion; Oswalt; McCook; Foran; Subasavage (2008). "A New Look at the Local White Dwarf Population". The Astronomical Journal. 135 (4): 1225–1238. Bibcode:2008AJ....135.1225H. doi:10.1088/0004-6256/135/4/1225. S2CID 122855486.
  4. ^ a b c d e Sion, Edward M.; Holberg; Oswalt; McCook; Wasatonic (2009). "The White Dwarfs within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal. 138 (6): 1681–1689. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. S2CID 119284418.
  5. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  6. ^ a b Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
  7. ^ Bagnulo, Stefano; Landstreet, John D. (2020), "Discovery of six new strongly magnetic white dwarfs in the 20 pc local population", Astronomy & Astrophysics, 643: A134, arXiv:2010.05795, Bibcode:2020A&A...643A.134B, doi:10.1051/0004-6361/202038565, S2CID 222290583