Astronomy:Nu2 Sagittarii
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 55m 07.14098s[1] |
| Declination | −22° 40′ 16.8185″[1] |
| Apparent magnitude (V) | +4.98[2] |
| Characteristics | |
| Spectral type | K1 Ib–II[3] |
| B−V color index | +1.32[2] |
| Astrometry | |
| Radial velocity (Rv) | −109.6[2] km/s |
| Proper motion (μ) | RA: −109.04[1] mas/yr Dec.: −35.25[1] mas/yr |
| Parallax (π) | 11.91 ± 0.52[1] mas |
| Distance | 270 ± 10 ly (84 ± 4 pc) |
| Absolute magnitude (MV) | +0.38[4] |
| Details | |
| ν2 Sgr A | |
| Mass | 1.44[2] M☉ |
| Radius | 85[5] R☉ |
| Luminosity | 120[2] L☉ |
| Surface gravity (log g) | 1.03[6] cgs |
| Temperature | 4,244±57[2] K |
| Metallicity [Fe/H] | −0.13[6] dex |
| Age | 4.52[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Nu2 Sagittarii (ν2 Sagittarii), also named Pabilsang,[8] is a binary star[9] system in the zodiac constellation of Sagittarius. It is faintly visible to the naked eye, having an apparent visual magnitude of +4.98;[2] it is 0.16 degree north of the ecliptic. The annual parallax shift of 11.91 mas as seen from Earth,[1] indicates this system is roughly 270 light years from the Sun. Nu2 Sagittarii has a high peculiar velocity of 86.0+11.6
−14.4 km/s and is most likely a runaway star system.[3]
The spectrum of the primary component displays a stellar classification of K1 Ib–II,[3] indicating this is a K-type star with a mixed luminosity class of an evolved bright giant/supergiant star. It is a mild barium star, showing an enhanced abundance of s-process elements in its outer atmosphere. This material was most likely acquired during a previous mass transfer from its now white dwarf companion.[10] The primary has an estimated 1.4[2] times the mass of the Sun and has expanded to 85[5] times the Sun's radius.
Pabilsaĝ was the original Sumerian name of the constellation Sagittarius; a god depicted as a centaur-like hybrid creature with a scorpion tail and wings. The IAU Working Group on Star Names adopted the name Pabilsang for this star on 13 August 2026.[8]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L.
- ↑ 3.0 3.1 3.2 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 5.0 5.1 Pasinetti Fracassini, L. E. et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics 367 (2): 521–24, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ 6.0 6.1 Soubiran, C. et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics 515: A111, doi:10.1051/0004-6361/201014247, Bibcode: 2010A&A...515A.111S.
- ↑ "nu02 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=nu02+Sgr.
- ↑ 8.0 8.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Gomez, A. E. et al. (1997), "Absolute magnitudes and kinematics of barium stars", Astronomy and Astrophysics 319: 881, Bibcode: 1997A&A...319..881G.
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