PSR B1257+12 A
Exoplanet | List of exoplanets | |
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300px (Based on selected hypothetical modeled compositions) |
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Parent star | ||
Star | PSR B1257+12 | |
Constellation | Virgo | |
Right ascension | (α) | 13h 00m 01s |
Declination | (δ) | +12° 40′ 57″ |
Distance | 980 ly (300 pc) |
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Spectral type | Pulsar | |
Mass | (m) | assumed 1.4 M☉ |
Radius | (r) | ~0.00002 R☉ |
Age | 0.8 Gyr | |
Orbital elements | ||
Semi-major axis | (a) | 0.19[1] AU |
Eccentricity | (e) | 0.0[1] |
Orbital period | (P) | 25.262 ± 0.003[1] d |
Inclination | (i) | 50[1][note 1]° |
Time of periastron | (T0) | 2,449,765.6 ± 0.2[1] JD |
Physical characteristics | ||
Mass | (m) | 0.020 ± 0.002[1][note 1] M⊕ |
Discovery information | ||
Discovery date | 22 April 1994 | |
Discoverer(s) | <templatestyles src="Plainlist/styles.css"/> | |
Discovery method | Pulsar timing | |
Discovery site | United States[2] | |
Discovery status | Published | |
Database references | ||
Extrasolar Planets Encyclopaedia |
data | |
SIMBAD | data | |
Exoplanet Archive | data | |
Open Exoplanet Catalogue | data |
PSR B1257+12 b (ex PSR B1257+12 A) or Draugr is an exoplanet (or extrasolar planet) approximately 980 light-years away in the constellation of Virgo. The planet is the innermost object orbiting the pulsar PSR B1257+12, i.e. a pulsar planet in the dead stellar system. It is about twice as massive as the Moon, and is listed as the least massive exoplanet known, including among the planets in the Solar System.[2]
Contents
Name
The planets of PSR B1257+12 are designated from A to D (ordered by increasing distance). The reason that these planets are not named the same as other extrasolar planets is mainly because of time. Being the first extrasolar planets discovered, and being discovered around a pulsar, the planets were given the uppercase letters "B" and "C" (like other planets). When a third planet was discovered around the system (in a closer orbit than the other two), the name "A" was commonly used. The extrasolar planet name 51 Pegasi b (the first planet found around a Sun-like star) was the template used for naming planets. Although these pulsar planets were not officially renamed, some have done it themselves. PSR B1257+12 A is catalogued as "PSR 1257+12 b" in The Extrasolar Planets Encyclopaedia.
The planet with its host star is one of the planetary systems selected by the International Astronomical Union as part of their public process for giving proper names to exoplanets and their host star (where no proper name already exists).[3][4] The process involved public nomination and voting for the new names.[5] In December 2015, the IAU announced the winning names were Draugr for the planet and Lich for the pulsar.[6]
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Notes
- ↑ 1.0 1.1 The value of the inclination is assumed to be 50° based on the inclinations of the other two planets in the system, which have inclinations of 53° and 47° respectively. The quoted mass value is based on this assumed inclination.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
- ↑ NameExoWorlds.
- ↑ NameExoWorlds.
- ↑ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
- Lua error in package.lua at line 80: module 'strict' not found.
External links
Media related to Lua error in package.lua at line 80: module 'strict' not found. at Wikimedia Commons
Preceded by | Least massive exoplanet 1994 — |
Succeeded by |
Coordinates: 13h 00m 01s, +12° 40′ 57″
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