G 99-47

From Wikipedia, the free encyclopedia
Jump to: navigation, search

Coordinates: Sky map 05h 56m 25.47s, +05° 21′ 48.6″

G 99-47
Observation data
Epoch J2000[1]      Equinox J2000[1]
Constellation Orion
Right ascension 05h 56m 25.47s[1]
Declination +05° 21′ 48.6″[1]
Apparent magnitude (V) 14.105[2]
Characteristics
Spectral type DAP8.9[3]
Apparent magnitude (B) 14.69[1]
Apparent magnitude (V) 14.10[1]
Apparent magnitude (R) 14.0[1]
Apparent magnitude (I) 13.6[1]
Apparent magnitude (J) 12.930 ± 0.022[1]
Apparent magnitude (H) 12.720 ± 0.025[1]
Apparent magnitude (K) 12.653 ± 0.024[1]
Astrometry
Proper motion (μ) RA: -434[3] mas/yr
Dec.: -931[3] mas/yr
Parallax (π) 125.0 ± 3.6[4] mas
Distance 26.1 ± 0.8 ly
(8.0 ± 0.2 pc)
Absolute magnitude (MV) 14.59[2][4][note 1]
Details
Mass 0.71 ± 0.03[2] M
Radius 0.011[2][note 2] R
Surface gravity (log g) 8.20 ± 0.05[2] cgs
Temperature 5790 ± 110[2] K
Age 3.97[3][note 3] Gyr
Other designations
WD 0553+053,[2][3] V1201 Ori,[1] LHS 212,[2] LTT 17891,[1] NLTT 15834,[1] G 099-047,[4] GJ 1087,[1] G 102-40,[1] G 106-15,[1] EGGR 290,[1] 2MASS J05562547+0521486,[1] USNO-B1.0 0953-00073703[1]
Database references
SIMBAD data

G 99-47 (V1201 Orionis) is a nearby degenerate star (white dwarf) of spectral class DAP8 (DAP8.9,[3] or DAP8.7[2]), the single known component of the system, located in the constellation Orion.

Distance[edit]

G 99-47 is probably the tenth closest white dwarf (or possibly the 9th–12th: see Gliese 293, Gliese 518 and Gliese 915). Its trigonometric parallax from the Yale Parallax Catalog is 0.1250 ± 0.0036 arcsec,[4] corresponding to a distance 8.00 ± 0.23 pc, or 26.09 ± 0.75 ly.

Parallax data

Source Paper Parallax, mas Distance, pc Distance, ly Ref.
Nearby Stars, 3rd ed. prelim., 3rd version Gliese, Jahreiss, 1991 125.1 ± 4.1 7.99 ± 0.26 26.07 ± 0.85 [5]
YPC, 4th edition van Altena et al., 1995 125.0 ± 3.6 8.00 ± 0.23 26.09 ± 0.75 [4]

Physical parameters[edit]

G 99-47's mass is 0.71 ± 0.03 Solar masses;[2] its surface gravity is 108.20 ± 0.05 (1.58 · 108) cm·s−2,[2] or approximately 162 000 of Earth's, corresponding to a radius 7711 km, or 121% of Earth's.

Its temperature is 5790 ± 110 K,[2] 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.[3] Due almost equal to the Sun's temperature, GJ 1087 should appear almost the same color as the Sun.

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. ^ 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. 
  2. ^ 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: 1225–1238. Bibcode:2008AJ....135.1225H. doi:10.1088/0004-6256/135/4/1225. 
  3. ^ a b c d e f g 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. 
  4. ^ a b c d e Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
  5. ^ Nearby Stars, Preliminary 3rd Version (Gliese+ 1991)