Pi Lupi

π Lupi (Latinised to Pi Lupi) is a multiple star system in the southern constellation Lupus. Two components form a wide binary pair with an orbital period of 517 years and a semimajor axis of 1.59″. They belong to the Upper Centaurus Lupus component of the Sco–Cen complex.[4]

π Lupi

A light curve for Pi Lupi, adapted from Sharma et al. (2022)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Lupus
Right ascension 15h 05m 07.08596s[2]
Declination −47° 03′ 04.4976″[2]
Apparent magnitude (V) 3.89[3]
Characteristics
Spectral type B5V + B5IV[4]
U−B color index −0.59[3]
B−V color index −0.14[3]
Astrometry
Radial velocity (Rv)+4.50[5] km/s
Proper motion (μ) RA: −22.98[2] mas/yr
Dec.: −22.81[2] mas/yr
Parallax (π)7.36 ± 0.55 mas[2]
Distance440 ± 30 ly
(140 ± 10 pc)
Details
A
Mass4.5[6] M☉
Surface gravity (log g)4.5[6] cgs
Temperature16,000[6] K
Rotational velocity (v sin i)10[6] km/s
B
Mass4.7[6] M☉
Temperature14,000[6] K
Rotational velocity (v sin i)10[6] km/s
Age14[6] Myr
Other designations
CD−46°9773, HIP 73807, SAO 225426
π Lupi A: HD 133242, HR 5605
π Lupi B: HD 133243, HR 5606
Database references
SIMBADdata
A
B

At least one of the components is a spectroscopic binary and produces eclipses 15.5 days apart, making it an eclipsing binary. There are also other brightness variations with a period of 16 hours that are likely to be pulsations of the Slowly pulsating B-type star. The eclipses are shallow, with the brightness dropping by only 1% or about 0.01 magnitudes. The amplitude of the pulsations is even smaller.[1]

π Lupi A (HR 5605, HD 133242) has been classified as a spectroscopic binary by at least two studies,[7][8] but both components may be spectroscopic binaries.[9]

References
  1. Sharma, Awshesh N.; Bedding, Timothy R.; Saio, Hideyuki; White, Timothy R. (2022), "Pulsating B stars in the Scorpius–Centaurus Association with TESS", Monthly Notices of the Royal Astronomical Society, 515 (1): 828–840, arXiv:2203.02582, Bibcode:2022MNRAS.515..828S, doi:10.1093/mnras/stac1816
  2. 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 18759600Vizier catalog entry
  3. Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N
  4. Nitschelm, C. (December 2004), Hilditch, R. W.; Hensberge, H.; Pavlovski, K. (eds.), "Discovery and confirmation of some double-lined spectroscopic binaries in the Sco-Cen Complex", Spectroscopically and Spatially Resolving the Components of the Close Binary Stars, Proceedings of the Workshop held 20–24 October 2003 in Dubrovnik, Croatia., ASP Conference Series, Astronomical Society of the Pacific, vol. 318, pp. 291–293, Bibcode:2004ASPC..318..291N
  5. Kharchenko, N. V.; et al. (2007), "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations", Astronomische Nachrichten, 328 (9): 889–896, arXiv:0705.0878, Bibcode:2007AN....328..889K, doi:10.1002/asna.200710776, S2CID 119323941
  6. Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah (25 July 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 40, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, eISSN 1538-3881
  7. Buscombe, W.; Stoeckley, T. R. (1975), "Absorption Line Profiles and Rotational Velocities for 59 Stars", Astrophysics and Space Science, 37 (1): 197, Bibcode:1975Ap&SS..37..197B, doi:10.1007/BF00646073, S2CID 122985118
  8. Chini, R.; Hoffmeister, V. H.; Nasseri, A.; Stahl, O.; Zinnecker, H. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x, S2CID 119120749
  9. Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
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