Xi Puppis
Star in the constellation Puppis
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Xi Puppis (ξ Puppis, abbreviated Xi Pup, ξ Pup) is a multiple star system in the southern constellation of Puppis. With an apparent visual magnitude of 3.35,[2] it is one of the brighter members of this constellation. Based on parallax measurements made during the Hipparcos mission, it is located approximately 1,200 light-years (370 parsecs) from the Sun, with a 7.5% margin of error.[1]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Puppis |
| Right ascension | 07h 49m 17.65567s[1] |
| Declination | −24° 51′ 35.2305″[1] |
| Apparent magnitude (V) | 3.35[2] |
| Characteristics | |
| Spectral type | G6 Iab-Ib[3] |
| U−B color index | +1.18[2] |
| B−V color index | +1.25[2] |
| Astrometry | |
| Radial velocity (Rv) | +2.7[4] km/s |
| Proper motion (μ) | RA: −4.81[1] mas/yr Dec.: −0.89[1] mas/yr |
| Parallax (π) | 2.72±0.21 mas[1] |
| Distance | 1,200 ± 90 ly (370 ± 30 pc) |
| Absolute magnitude (MV) | –3.89[5] |
| Details | |
| Mass | 9.9 ± 1.0[3] M☉ |
| Radius | 124[6] R☉ |
| Luminosity | 6,824±641[6] L☉ |
| Surface gravity (log g) | 1.21±0.14[3] cgs |
| Temperature | 4,712±125,[6] 4,925[5] K |
| Metallicity [Fe/H] | +0.13[5] dex |
| Rotational velocity (v sin i) | 9.2[7] km/s |
| Age | 23[3] Myr |
| Other designations | |
| Azmidi, Azmidiske, Asmidiske, ξ Puppis, ξ Pup, Xi Pup, 7 Puppis, CCDM J07493-2452A; CPD−24 2939, FK5 1204, GC 10562, HD 63700, HIP 38170, HR 3045, IDS 07451-2437 A, PPM 253258, SAO 174601, WDS J07493-2452A. | |
| Database references | |
| SIMBAD | data |
The system consists of a spectroscopic binary, designated Xi Puppis A,[8] together with a third companion star, Xi Puppis B. A's two components are themselves designated Xi Puppis Aa (formally named Azmidi /ˈæzmɪdi/)[9] and Ab.
Nomenclature
ξ Puppis (Latinised to Xi Puppis) is the system's Bayer designation. The designations of the two constituents as Xi Puppis A and B, and those of A's components - Xi Puppis Aa and Ab - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[10]
The system was sometimes known as Asmidiske (Azmidiske), a misspelling and misplacement of Aspidiske (from the Greek for 'little shield), the traditional name of Iota Carinae.[11] In 2016, the IAU organized a Working Group on Star Names (WGSN)[12] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[13] It approved the name Azmidi for the component Xi Puppis Aa on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[9]
Properties
Because of the distance of this system from the Earth, its visual magnitude is reduced by 0.73 as a result of extinction from the intervening gas and dust.[14]
Xi Puppis A presents as a yellow supergiant of spectral class G6 with a luminosity 8,300 times that of the Sun.[11]
The 13th-magnitude companion, Xi Puppis B, is about 5 arcseconds distant and is a Sun-like star that orbits at least 2000 AU away with an orbital period of at least 26,000 years.[11]