This is a list of exceptional white dwarf stars. An extensive database of all known white dwarfs and their properties is available in the Montreal White Dwarf Database. [1]
These were the first white dwarfs discovered fitting these conditions
Title | Star | Date | Data | Comments | Notes | Refs |
---|---|---|---|---|---|---|
First discovered | Sirius B | 1852 | Sirius system | Sirius B is also the nearest white dwarf (as of 2005) | [2] [3] | |
First found in a binary star system | ||||||
First double white dwarf system | LDS 275 | 1944 | L 462-56 system | [4] | ||
First solitary white dwarf | Van Maanen 2 | 1917 | Van Maanen's star is also the nearest solitary white dwarf | [5] | ||
First white dwarf with a planet | WD B1620−26 | 2003 | PSR B1620-26 b (planet) | This planet is a circumbinary planet, which circles both stars in the PSR B1620-26 system | [6] [7] | |
First singular white dwarf with a transiting object | WD 1145+017 | 2015 | Known object is a disintegrating planetesimal, most likely an asteroid. | [8] | ||
First white dwarf that is a pulsar | AR Scorpii A | 2016 | The star is in a binary system with a red dwarf | [9] | ||
These are the white dwarfs which are currently known to fit these conditions
Title | Star | Date | Data | Comments | Notes | Refs |
---|---|---|---|---|---|---|
Nearest | Sirius | 1852 | 8.6 ly (2.6 pc ) | Sirius B is also the second white dwarf discovered. | [2] [3] | |
Farthest | SN UDS10Wil progenitor | 2013 | 10,000,000,000 ly z=1.914 | SN Wilson is a type-Ia supernova whose progenitor was a white dwarf | [10] [11] [12] | |
Oldest | WD 0346+246 | 2021 | 11.5 billion years | [13] | ||
Youngest | ||||||
Highest surface temperature | RX J0439.8−6809 | 2015 | 250,000 K (250,000 °C ; 450,000 °F ) | This star is located in the Milky Way's galactic halo, in the field of the Large Magellanic Cloud | [14] [15] [13] | |
Lowest surface temperature | PSR J2222–0137 B WD J2147–4035 | 2021 2022 | 3000K 3050 K | in binary single | [13] [16] | |
Most luminous | Central star of the Skull Nebula | 2018 | 18,620+7,630 −10,990 L☉ | [17] | ||
Least luminous | WD 0343+247 | 1.62×10−5 L☉ | [18] [19] | |||
Brightest apparent | Sirius B | 1852 | 8.44 (V) | |||
Dimmest apparent | ||||||
Most massive | ZTF J1901+1458 [20] | 2020 | 1.35 M☉ | [20] | ||
Least massive | NLTT 11748 | 2007 | 0.13–0.16 M☉ | [13] | ||
Largest | Z Andromedae B | 0.17—0.36 R☉ | [21] | |||
Smallest | HD 49798 | 2021 | 0.0023 R☉ | [22] |
Star | Distance | Comments | Notes | Refs | |
---|---|---|---|---|---|
Sirius B | 8.58 ly (2.63 pc) | Sirius B is also the second white dwarf discovered. It is part of the Sirius system. | [2] [3] [23] [24] | ||
Procyon B | 11.43 ly (3.50 pc) | Part of Procyon system | [23] [24] | ||
van Maanen's Star | 14.04 ly (4.30 pc) | [23] [24] | |||
GJ 440 | 15.09 ly (4.63 pc) | [23] | |||
40 Eridani B | 16.25 ly (4.98 pc) | Part of 40 Eridani system | [23] [24] | ||
Stein 2051 B | 18.06 ly (5.54 pc) | Part of Stein 2051 system | [23] [24] | ||
LP 44-113 | 20.0 ly (6.1 pc) | [24] | |||
G 99-44 | 20.9 ly (6.4 pc) | [24] | |||
L 97-12 | 25.8 ly (7.9 pc) | [24] | |||
Wolf 489 | 26.7 ly (8.2 pc) | [24] | |||
A supernova is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the progenitor, either collapses to a neutron star or black hole, or is completely destroyed to form a diffuse nebula. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months.
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place in a white dwarf; what light it radiates is from its residual heat. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name white dwarf was coined by Willem Jacob Luyten in 1922.
Van Maanen 2, or van Maanen's Star, is the closest known solitary white dwarf to the Solar System. It is a dense, compact stellar remnant no longer generating energy and has equivalent to about 68% of the Sun's mass but only 1% of its radius. At a distance of 14.1 light-years it is the third closest of its type of star after Sirius B and Procyon B, in that order. Discovered in 1917 by Dutch–American astronomer Adriaan van Maanen, Van Maanen 2 was the third white dwarf identified, after 40 Eridani B and Sirius B, and the first solitary example.
HD 38529 is a binary star approximately 138 light-years away in the constellation of Orion.
A Type Ia supernova is a type of supernova that occurs in binary systems in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf.
GD 362 is a white dwarf approximately 150 light years from Earth. In 2004, spectroscopic observations showed that it had a relatively high concentration of metals in its atmosphere. Since the high gravitational field of white dwarfs quickly forces heavy elements to settle towards the bottom of the atmosphere, this meant that the atmosphere was being polluted by an external source. In 2005, infrared photometric observations suggested that it was surrounded by a ring of dust with size comparable to the rings of Saturn, providing an explanation for this pollution.
A circumbinary planet is a planet that orbits two stars instead of one. The two stars orbit each other in a binary system, while the planet typically orbits farther from the center of the system than either of the two stars. In contrast, circumstellar planets in a binary system have stable orbits around one of the two stars, closer in than the orbital distance of the other star. Studies in 2013 showed that there is a strong hint that a circumbinary planet and its stars originate from a single disk.
An exocomet, or extrasolar comet, is a comet outside the Solar System, which includes rogue comets and comets that orbit stars other than the Sun. The first exocomets were detected in 1987 around Beta Pictoris, a very young A-type main-sequence star. There are now a total of 27 stars around which exocomets have been observed or suspected.
In astronomy, a calcium-rich supernova is a subclass of supernovae that, in contrast to more well-known traditional supernova classes, are fainter and produce unusually large amounts of calcium. Since their luminosity is located in a gap between that of novae and other supernovae, they are also referred to as "gap" transients. Only around 15 events have been classified as a calcium-rich supernova – a combination of their intrinsic rarity and low luminosity make new discoveries and their subsequent study difficult. This makes calcium-rich supernovae one of the most mysterious supernova subclasses currently known.
Ross 640 is a white dwarf star in the northern constellation of Hercules, positioned near the constellation border with Corona Borealis. With an apparent visual magnitude of 13.83, it is too faint to be visible to the naked eye. Its trigonometric parallax from the Gaia mission is 62.9″, corresponding to a distance of 52 light-years.
WD J2356−209 is a white dwarf star located 65 pc away from the Earth. It is a very faint white dwarf, with an apparent visual magnitude of 21.03. Its visible spectrum is dominated by a broad absorption feature that has been attributed to pressure-broadened sodium D lines. The presence of this sodium absorption feature and the detection of spectral lines from other heavy elements indicate that the photosphere of WD J2356−209 has been polluted by a recent rocky debris accretion episode. A detailed analysis of the spectrum of WD J2356−209 shows that the accreted planetesimal was abnormally sodium-rich, containing up to ten times more sodium than calcium. With an effective temperature of 4040 K, WD J2356−209 was the coolest metal-polluted white dwarf observed at the time.
ESO 439-26 was considered the least luminous white dwarf known. Located 140 light years away from the Sun, it is roughly 10 billion years old and has a temperature of 4560 Kelvin. Thus, despite being classified as a "white dwarf", it would actually appear yellowish in color.
WD 1856+534 is a white dwarf located in the constellation of Draco. At a distance of about 25 parsecs (80 ly) from Earth, it is the outer component of a visual triple star system consisting of an inner pair of red dwarf stars, named G 229-20. The white dwarf displays a featureless absorption spectrum, lacking strong optical absorption or emission features in its atmosphere. It has an effective temperature of 4,700 K, corresponding to an age of approximately 5.8 billion years. WD 1856+534 is approximately half as massive as the Sun, while its radius is much smaller, being 40% larger than Earth.
SDSS J1228+1040 is a white dwarf with a debris disk around it. The disk formed when a planetary body was tidally disrupted around the white dwarf. It is the first gaseous disk discovered around a white dwarf.
SDSS 1557 is a binary system composed of a white dwarf and a brown dwarf. The system is surrounded by a circumbinary debris disk. The debris disk was formed when a minor planet was tidally disrupted around the white dwarf in the past.
GALEX J2339–0424 is a white dwarf that is suspected to be polluted with material originating from an icy exomoon. This is evident from the first detection of beryllium in this white dwarf, together with GD 378.
WD 2317+1830 is one of the first white dwarfs with lithium detected in its atmosphere. The white dwarf is surrounded by a debris disk and is actively accreting material. Researchers suggest that the presence of alkali metals indicates the accretion of crust material. Another work however cautions to use alkali metals as a single indicator of crust material. They suggest that such objects could be polluted by mantle material instead. An analysis in 2024 finds that the abundance of lithium is in agreement with Big Bang nucleosynthesis (BBN) and galactic nucleosynthesis. WD 2317+1830 likely was a star with sub-solar metallicity, which is evident from its old age, as well as from its thick disk or halo kinematics. This low metallicity means that the planetesimals that formed around this old white dwarf had a composition more similar to BBN abundances. The lithium-enhancement is not in agreement with the accretion of terrestrial continental crust material. The accretion of an exotic exoplanet is not ruled out, but the accretion of a primitive planetesimal is more likely. The accretion of an exomoon as a lithium source is excluded.