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About 6% of white dwarfs show infrared excess due to a disk around a white dwarf. [66] In the past only a relative small sample of white dwarf disks was known. [67] Due to advances in white dwarf detection (e.g. with Gaia or LAMOST) and improvement of WISE infrared catalogs with unWISE/CatWISE, the number has increased to hundreds of candidates.
An accretion disk is a structure (often a circumstellar disk) formed by diffuse material [a] in orbital motion around a massive central body. The central body is most frequently a star . Friction , uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward ...
[1] [2] Until 2021 it was the oldest and coldest white dwarf known to host a disk. The white dwarf WD 2317+1830 with a detected disk is at least twice as old and around 2,000 K colder. [3] [4] The white dwarf has a radius of 0.011 R ☉, which is about 1.2 times the radius of the earth. Because white dwarfs are such dense objects, LSPM J0207 ...
Matter is stripped from a white dwarf (sphere at lower right) orbiting within the innermost accretion disk surrounding 1ES 1927+654's supermassive black hole.
While old white dwarfs show evidence of dust accretion, white dwarfs older than ~1 billion years or >7000 K with dusty infrared excess were not detected [177] until the discovery of LSPM J0207+3331 in 2018, which has a cooling age of ~3 billion years. The white dwarf shows two dusty components that are being explained with two rings with ...
The researchers also detected infrared excess, indicative of a debris disk, around this white dwarf. The disk is inclined by 70°, has an inner disk temperature of 1,500 K and an outer disk temperature of 500 K. In the past WD 2317+1830 had a mass of 4.8 ± 0.2 M ☉ and was likely a B-type star. [3]
In intermediate polar systems, material stripped from a red dwarf secondary star flows into an accretion disk around the white dwarf, but the inner disk is truncated by the magnetic field of the white dwarf. In extreme instances, the disk can be fully disrupted, although this is uncommon. [2] In the region where the disk is truncated, the gas ...
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 ...