Zeta Pyxidis

Zeta Pyxidis (ζ Pyxidis) is a wide binary star^[9] system in the southern constellation of Pyxis. It is visible to the naked eye with a combined apparent visual magnitude of +4.88.^[2] Based upon an annual parallax shift of 13.35 mas as seen from Earth,^[1] it is located around 244 light years from the Sun.

Zeta Pyxidis

Location of ζ Pyxidis (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Pyxis
Right ascension	08h 39m 42.47410s[1]
Declination	−29° 33′ 39.8989″[1]
Apparent magnitude (V)	+4.88[2] (4.97 + 9.59)[3]
Characteristics
Spectral type	G6 IIIb CN-0.5[4]
B−V color index	+0.90[2]
Astrometry
Radial velocity (Rv)	−30.10[5] km/s
Proper motion (μ)	RA: −24.81[1] mas/yr Dec.: −90.96[1] mas/yr
Parallax (π)	13.35 ± 0.23 mas[1]
Distance	244 ± 4 ly (75 ± 1 pc)
Absolute magnitude (MV)	+0.49[6]
Details
ζ Pyx A
Mass	1.96[5] M☉
Luminosity	69[5] L☉
Surface gravity (log g)	2.72±0.06[7] cgs
Temperature	4,876±8[5] K
Metallicity [Fe/H]	−0.43±0.02[7] dex
Age	1.88[5] Gyr
Other designations
ζ Pyx, CPD−29° 2756, FK5 2680, HD 73898, HIP 42483, HR 3433, SAO 176253, WDS J08397-2934A[8]
Database references
SIMBAD	data

The yellow-hued primary, component A, is an evolved G-type giant star with a stellar classification of G6 IIIb CN-0.5,^[4] where the suffix notation indicating it has anomalously weak lines of cyanogen. At the age of 1.88 billion years,^[5] is a red clump star that is generating energy through the fusion of helium at its core.^[10] The primary has nearly double the mass of the Sun and is radiating 69 times the Sun's luminosity from its photosphere at an effective temperature of 4,876 K.^[5]

The companion, component B, is a magnitude 9.59 star at an angular separation of 52.20 arc seconds along a position angle of 61°, as of 2010.^[3]

References

1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
2. Cousins, A. W. J.; et al. (1966), "Photoelectric magnitudes and colours of southern stars, II", Royal Observatory Bulletins, 121: 1, Bibcode:1966RGOB..121....1C.
3. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
4. Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373, S2CID 123149047.
5. Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
6. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
7. Alves, S.; et al. (April 2015), "Determination of the spectroscopic stellar parameters for 257 field giant stars", Monthly Notices of the Royal Astronomical Society, 448 (3): 2749–2765, arXiv:1503.02556, Bibcode:2015MNRAS.448.2749A, doi:10.1093/mnras/stv189, S2CID 119217930.
8. "zet Pyx". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-16.
9. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
10. Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.