WD 2359-434 (Gliese 915, LHS 1005, L 362-81) is a nearby degenerate star (white dwarf) of spectral class DAP5.8,^[3] the single known component of the system, located in the constellation Phoenix, the nearest star in this constellation.

Quick Facts Constellation, Right ascension ...

WD 2359−434

Size of WD 2359−434 in comparison with Earth. On the left is Earth, on the right is WD 2359-434.
Observation data Epoch J2000[1]      Equinox J2000[1]
Constellation	Phoenix
Right ascension	00h 02m 10.766s[1]
Declination	−43° 09′ 56.02″[1]
Apparent magnitude (V)	12.76[2]
Characteristics
Spectral type	DAP5.8[3]
Apparent magnitude (B)	13.12[1]
Apparent magnitude (V)	12.76[2]
Apparent magnitude (RKC)	12.82[4]
Apparent magnitude (IKC)	12.66[4]
Apparent magnitude (J)	12.60 ± 0.03[4]
Apparent magnitude (H)	12.43 ± 0.02[4]
Apparent magnitude (KS)	12.45 ± 0.02[4]
Astrometry
Radial velocity (Rv)	-58.8 ± 10.8[5] km/s
Proper motion (μ)	RA: 589[4] mas/yr Dec.: -664[4] mas/yr
Parallax (π)	120.0143 ± 0.0215 mas[6]
Distance	27.176 ± 0.005 ly (8.332 ± 0.001 pc)
Absolute magnitude (MV)	13.20[2][4][note 1]
Details
Mass	0.85 ± 0.01[4] M☉
Radius	0.0097[4][note 2] R☉
Surface gravity (log g)	8.39 ± 0.01[4] cgs
Temperature	8570 ± 50[2] K
Age	1.82 ± 0.06[4][note 3] Gyr
Other designations
Gliese 915,[2][3] LHS 1005,[2] LFT 1849,[1] LTT 9857,[1] LP 988-88,[1] L 362-81,[7] EGGR 165,[1] LAWD 96,[1] 2MASS J00021076-4309560[1]
Database references
SIMBAD	data
WD 2359−434 Location of WD 2359−434 in the constellation Phoenix

Close

WD 2359−434, probably, is the 11th closest white dwarf, or, possibly, 9th, 10th, or 12th (see Gliese 293, GJ 1087 and Gliese 518). Currently, the most accurate distance estimate of WD 2359−434 is trigonometric parallax from CTIOPI (Cerro Tololo Inter-American Observatory Parallax Investigation) 0.9 m telescope program, published in 2009 in the 21st paper of RECONS's The Solar Neighborhood (TSN) series^[8] Subasavage et al. 2009:^[4] 122.27 ± 1.13 mas, corresponding to a distance 8.18 ± 0.08 pc, or 26.68 ± 0.25 ly.

The most accurate estimate is marked in bold.

WD 2359−434's mass is 0.85 ± 0.01 Solar masses,^[4] its surface gravity is 10^{8.39 ± 0.01} (2.45 · 10⁸) cm·s⁻²,^[4] or approximately 250,000 of Earth's, corresponding to a radius 6780 km, or 1.06 of Earth's.

WD 2359−434 is relatively hot and young white dwarf, its temperature is 8570 ± 50 K;^[2] its cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star) is 1.82 ± 0.06 Gyr.^[4] Gliese 518 should appear bluish-white, due temperature, comparable with that of A-type main sequence stars.

As all white dwarfs, WD 2359−434 is composed of very dense degenerate matter, its mean density is 1,300,000 g·cm⁻³,^{[4][note 4]} i.e. mass of one cubic millimetre of WD 2359−434 matter is 1.3 kg.

Unusually for a white dwarf star, WD 2359-434 has a weak, non-dipole magnetic field of 50,000 - 100,000 Gauss.^[11]

As all degenerate stars, WD 2359−434 previously existed initially as main-sequence star and then as giant star, until all the thermonuclear fuel was exhausted, after which WD 2359−434 lost most of its mass. According to the 2010 thesis for the degree of Doctor of Science,^[12] using Wood model D^[13] initial–final mass relation and WD 2359−434's white dwarf mass value 0.97 ± 0.03 M_☉ from Holberg et al. 2008,^[2] its main sequence progenitor mass was 7.09 M_☉. Using expression for pre-white dwarf lifetime 10 · (M_MS/M_☉)^2.5 (Gyr),^[13] was found WD 2359−434 main sequence age 0.07 Gyr.

White dwarf mass value 0.85 ± 0.01 M_☉ from Subasavage et al. 2009,^[4] in Wood model D yields MS (main sequence) mass 6.03 M_☉, and MS lifetime 0.11 Gyr, corresponding to B-type main sequence star.

According to initial-final mass relation from Weidemann 2000 paper,^[14] WD 2359−434's main sequence progenitor should have mass about 4.6 M_☉ and lifespan 0.22 Gyr, and, again, should be of B spectral type. There are also other models.

• List of star systems within 25–30 light-years