Chi Lupi

Chi Lupi (Chi Lup, χ Lupi, χ Lup) is a spectroscopic binary star in the constellation of Lupus.^[1] It has an apparent visual magnitude of approximately 3.957.^[1] The primary star in the binary is a mercury-manganese star of spectral type B9.5V; the secondary is a metallic-lined star of type A2Vm.^[2]

χ Lupi

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Lupus
Right ascension	15h 50m 57.5376s[1]
Declination	−33° 37′ 37.796″[1]
Apparent magnitude (V)	3.957[1]
Characteristics
Spectral type	B9.5V + A2Vm[2]
U−B color index	−0.13[3]
B−V color index	−0.04[3]
R−I color index	−0.07[3]
Astrometry
Radial velocity (Rv)	5 ± 20[1] km/s
Proper motion (μ)	RA: −5.92[1] mas/yr Dec.: −24.91[1] mas/yr
Parallax (π)	15.86 ± 0.84 mas[1]
Distance	210 ± 10 ly (63 ± 3 pc)
Details[4]
χ Lup A
Mass	2.84±0.12 M☉
Radius	2.85±0.15 R☉
Luminosity	63[5] L☉
Surface gravity (log g)	4.08[5] cgs
Temperature	10,200[5] K
Rotational velocity (v sin i)	0[3] km/s
Age	280±30 Myr
χ Lup B
Mass	1.94±0.09 M☉
Radius	1.75±0.18 R☉
Surface gravity (log g)	4.2 cgs
Temperature	9,200 K
Other designations
χ Lup, Chi Lupi, Chi Lup, 5 Lupi, 5 Lup, CD−33 10754, CPD−33 3933, FK5 586, GC 21281, HD 141556, HIP 77634, HR 5883, PPM 294334, SAO 207040.[1]
Database references
SIMBAD	data

This system is a proper motion member of the Upper Scorpius sub-group in the Scorpius–Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.^[5] The Upper Scorpius subgroup contains thousands of stars with an average age of 11 million years old at mean distances of 145 parsecs (470 light years).^[6]

References

1. "chi Lup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved August 14, 2008.
2. On the Ga II and Ga III Resonance Lines and the Implication for Chemical Stratification in HgMn Stars, K. E. Nielsen et al., Astronomical Journal 130, #5 (November 2005), pp. 2312–2317, Bibcode:2005AJ....130.2312N, doi:10.1086/491703.
3. HR 5883, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line August 14, 2008.
4. Le Bouquin, J.-B.; Beust, H.; Duvert, G.; Berger, J. P.; Ménard, F.; Zins, G. (March 2013), "Masses and age of the chemically peculiar double-lined binary χ Lupi", Astronomy & Astrophysics, 551: 9, arXiv:1302.5014, Bibcode:2013A&A...551A.121L, doi:10.1051/0004-6361/201220454, S2CID 13860888, A121.
5. de Geus, E. J.; de Zeeuw, P. T.; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics, 216 (1–2): 44–61, Bibcode:1989A&A...216...44D
6. Mark J. Pecaut; Eric E. Mamajek & Eric J. Bubar (February 2012). "A Revised Age for Upper Scorpius and the Star Formation History among the F-type Members of the Scorpius–Centaurus OB Association". Astrophysical Journal. 746 (2): 154. arXiv:1112.1695. Bibcode:2012ApJ...746..154P. doi:10.1088/0004-637X/746/2/154. S2CID 118461108.