Magnitude 12.76 Apparent magnitude (V) 12.76 Radius 0.0097 R☉ | Constellation Phoenix Surface gravity (log g) 8.39 ± 0.01 cgs | |
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Distance 26.7 ± 0.2 ly; (8.18 ± 0.08 pc) People also search for Mu Phoenicis, Psi Phoenicis | ||
WD 2359-434 (Gliese 915, LHS 1005, L 362-81) is a nearby degenerate star (white dwarf) of spectral class DAP5.8, the single known component of the system, located in the constellation Phoenix, the nearest star in this constellation.
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Distance
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 Subasavage et al. 2009: 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.
Physical parameters
WD 2359-434's mass is 0.85 ± 0.01 Solar masses, its surface gravity is 108.39 ± 0.01 (2.45 · 108) cm·s−2, 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; 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. 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, i.e. mass of one cubic millimetre of WD 2359-434 matter is 1.3 kg.
Main sequence progenitor properties
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 2010 thesis for the degree of Doctor of Science, using Wood model D initial–final mass relation and WD 2359-434's white dwarf mass value 0.97 ± 0.03 M☉ from Holberg et al. 2008, its main sequence progenitor mass was 7.09 M☉. Using expression for pre-white dwarf lifetime 10 · (MMS/M☉)2.5 (Gyr), 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, 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 initial-final mass relation from Weidemann 2000 paper, 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.