Xi Puppis

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]

ξ Puppis

Location of ξ Puppis (circled)
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]