Nu Pavonis

ν Pavonis, Latinized as Nu Pavonis, is a possible triple star system[11] in the southern constellation of Pavo. It is visible to the naked eye as a faint star that varies in apparent visual magnitude from 4.60 to 4.64 over a period of 0.85584 days.[2] The system lies approximately 440 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +17 km/s.[6] It is a possible member of the Wolf 630 group of co-moving stars.[3]

A light curve for Nu Pavonis, plotted from TESS data[12]
Not to be confused with NU Pavonis.
Nu Pavonis
Location of ν Pavonis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pavo
Right ascension 18h 31m 22.42509s[1]
Declination −62° 16′ 41.8853″[1]
Apparent magnitude (V) 4.64 (4.60 - 4.64[2])
Characteristics
Evolutionary stage main sequence[3]
Spectral type B7III[4]
U−B color index −0.39[5]
B−V color index −0.11[5]
Variable type SPB[2]
Astrometry
Radial velocity (Rv)+16.95[6] km/s
Proper motion (μ) RA: −1.11[1] mas/yr
Dec.: −45.31[1] mas/yr
Parallax (π)7.43 ± 0.24 mas[1]
Distance440 ± 10 ly
(135 ± 4 pc)
Absolute magnitude (MV)-1.01[4]
Orbit[7]
Period (P)1.711529±0.000005 d
Eccentricity (e)0.0
Periastron epoch (T)2,450,276.5502±0.0007 HJD
Argument of periastron (ω)
(secondary)		127±12°
Semi-amplitude (K1)
(primary)		43.8±0.1 km/s
Details
Mass4.39[8] M☉
Luminosity659[8] L☉
Temperature12,764[8] K
Rotational velocity (v sin i)125.0[9] km/s
Other designations
ν Pav, CD−62°1213, GC 25227, HD 169978, HIP 90797, HR 6916, SAO 254273, WDS J18314-6217AB[10]
Database references
SIMBADdata

This is a single-lined spectroscopic binary system with an orbital period of just 1.71 days in a circular orbit.[7] The unresolved[3] components are close enough that their tidal interaction is significant.[7] The visible component is a slowly pulsating B-type star with a stellar classification of B7III.[4] This implies it is an evolved giant star, but it is actually more likely to be on the main sequence. An X-ray emission has been detected from the pair.[3]

The third component is a visible companion, probably a pre-main-sequence star, at magnitude 13.7 and separation 3.1″. This star is estimated at 0.15 solar masses and an effective temperature of 3,192 K.[8] It too is an X-ray source.[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. Vizier catalog entry
  2. Watson, C. L. (2006). "The International Variable Star Index (VSX)". The Society for Astronomical Sciences 25th Annual Symposium on Telescope Science. Held May 23–25. 25: 47. Bibcode:2006SASS...25...47W.
  3. Stelzer, B.; et al. (September 2003). "Late B-type stars and their candidate companions resolved with Chandra". Astronomy and Astrophysics. 407 (3): 1067–1078. arXiv:astro-ph/0306401. Bibcode:2003A&A...407.1067S. doi:10.1051/0004-6361:20030934. S2CID 16766165.
  4. 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. Vizier catalog entry
  5. Ducati, J. R. (2002). "VizieR On-Line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  6. Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID 119387088.
  7. De Cat, P.; Aerts, C.; De Ridder, J.; Kolenberg, K.; Meeus, G.; Decin, L. (2000). "A study of bright southern slowly pulsating B stars. I. Determination of the orbital parameters and of the main frequency of the spectroscopic binaries". Astronomy and Astrophysics. 355: 1015–1030. Bibcode:2000A&A...355.1015D.
  8. Hubrig, S.; Le Mignant, D.; North, P.; Krautter, J. (2001). "Search for low-mass PMS companions around X-ray selected late B stars". Astronomy and Astrophysics. 372: 152–164. arXiv:astro-ph/0103201. Bibcode:2001A&A...372..152H. doi:10.1051/0004-6361:20010452. S2CID 17507782.
  9. Glebocki, R.; Gnacinski, P. (2005). "Catalog of Stellar Rotational Velocities". VizieR On-Line Data Catalog: III/244. 3244. Bibcode:2005yCat.3244....0G. Vizier catalog entry
  10. "nu. Pav". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-01.
  11. 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.
  12. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 24 September 2022.
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