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Alvan Graham Clark was born in Fall River, Massachusetts, the son of Alvan Clark, founder of Alvan Clark & Sons. [1]On January 31, 1862, while testing a new 18.5-inch (470 mm) aperture great refractor telescope in Cambridgeport, Massachusetts, Clark made the first ever observation of a white dwarf star.
Sirius B, which is a white dwarf, can be seen as a faint point of light to the lower left of the much brighter Sirius A. 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.
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− ...
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.
Sirius is a binary star consisting of a main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. The distance between the two varies between 8.2 and 31.5 astronomical units as they orbit every 50 years.
Iota Canis Majoris, lying between Sirius and Gamma, is another star that has been classified as a Beta Cephei variable, varying from magnitude 4.36 to 4.40 over a period of 1.92 hours. [36] It is a remote blue-white supergiant star of spectral type B3Ib, around 46,000 times as luminous as the sun and, at 2500 light-years distant, 300 times ...
1910 – the spectrum of 40 Eridani B is observed, making it the first confirmed white dwarf. 1914 – Walter Sydney Adams determines an incredibly high density for Sirius B. 1926 – Ralph Fowler uses Fermi–Dirac statistics to explain white dwarf stars. 1930 – Subrahmanyan Chandrasekhar discovers the white dwarf maximum mass limit.
The revised Yerkes Atlas system [7] listed a dense grid of A-type dwarf spectral standard stars, but not all of these have survived to this day as standards. The "anchor points" and "dagger standards" of the MK spectral classification system among the A-type main-sequence dwarf stars, i.e. those standard stars that have remained unchanged over years and can be considered to define the system ...