Gamma2 Normae

  1. Home
  2. Wiki
For other stars with this Bayer designation, see γ Normae.
Gamma2 Normae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Norma
Right ascension 16h 19m 50.42231s[1]
Declination −50° 09′ 19.8216″[1]
Apparent magnitude (V) 4.02[2]
Characteristics
Evolutionary stage Red clump[3]
Spectral type K0III[4]
U−B color index +1.16[5]
B−V color index +1.08[5]
Astrometry
Radial velocity (Rv)−29.15±0.42[1] km/s
Proper motion (μ) RA: −159.666 mas/yr[1]
Dec.: −51.94 mas/yr[1]
Parallax (π)23.5698±0.1272 mas[1]
Distance138.4 ± 0.7 ly
(42.4 ± 0.2 pc)
Absolute magnitude (MV)0.86±0.04[6]
Details
Mass2.06±0.23[6] M☉
Radius10.35±0.35[6] R☉
Luminosity49.7±2.2[6] L☉
Surface gravity (log g)2.750±0.171[6] cgs
Temperature4,763±63[6] K
Metallicity [Fe/H]+0.250±0.036[6] dex
Rotational velocity (v sin i)2.3[7] km/s
Age1.44[8] Gyr
Other designations
γ2 Nor, CD−49°10536, GC 12216, GJ 9554, HD 146686, HIP 80000, HR 6072, SAO 243643[9]
Database references
SIMBADdata
ARICNSdata

Gamma2 Normae, Latinized from γ2 Nor, is the brightest star in the southern constellation of Norma. Its apparent magnitude is 4.02[5] – making it a faint star but visible to the naked eye. Based upon an annual parallax shift of 23.57 mas as seen from Earth,[1] this star is located roughly 138 light years away. It is moving closer to the Sun with a radial velocity of −29 km/s.[1]

This is an evolved, orange-hued giant of spectral type K0 III.[4] A red clump star,[3] it has started the fusion of helium at its core and is now in the evolutionary stage known as the horizontal branch. The star is around 2.16 times as massive as the Sun and has grown to a diameter 10.35 times that of the Sun. The star is radiating 50 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,763 K.[6]

Gamma2 Normae is a double star, with a magnitude 10 companion 45″ away. The pair has been previously identified as a binary star system,[10] but parallax measurements the Gaia spacecraft data showed the companion star to be much more distant.[11] A white dwarf located 24.38" away[12] has similar distance and proper motion with Gamma2 Normae.[13]

References

[edit]
  1. ^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ Ducati, J. R. (2002), "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system.", VizieR Online Data Catalog, 2237, Bibcode:2002yCat.2237....0D.
  3. ^ a b Liu, Y. J.; Zhao, G.; Shi, J. R.; Pietrzyński, G.; Gieren, W. (December 2007), "The abundances of nearby red clump giants", Monthly Notices of the Royal Astronomical Society, 382 (2): 553–566, Bibcode:2007MNRAS.382..553L, doi:10.1111/j.1365-2966.2007.11852.x, ISSN 0035-8711.
  4. ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  5. ^ a b c Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  6. ^ a b c d e f g h Ottoni, G.; Udry, S.; Ségransan, D.; Buldgen, G.; Lovis, C.; Eggenberger, P.; Pezzotti, C.; Adibekyan, V.; Marmier, M.; Mayor, M.; Santos, N. C.; Sousa, S. G.; Lagarde, N.; Charbonnel, C. (2022-01-01), "CORALIE radial-velocity search for companions around evolved stars (CASCADES). I. Sample definition and first results: Three new planets orbiting giant stars", Astronomy and Astrophysics, 657: A87, arXiv:2201.01528, Bibcode:2022A&A...657A..87O, doi:10.1051/0004-6361/202040078, ISSN 0004-6361.
  7. ^ De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014). "A catalog of rotational and radial velocities for evolved stars. V. Southern stars". Astronomy and Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762.
  8. ^ Kordopatis, G.; Schultheis, M.; McMillan, P. J.; Palicio, P. A.; De Laverny, P.; Recio-Blanco, A.; Creevey, O.; Álvarez, M. A.; Andrae, R.; Poggio, E.; Spitoni, E.; Contursi, G.; Zhao, H.; Oreshina-Slezak, I.; Ordenovic, C.; Bijaoui, A. (2023). "Stellar ages, masses, extinctions, and orbital parameters based on spectroscopic parameters of Gaia DR3". Astronomy and Astrophysics. 669: A104. arXiv:2206.07937. Bibcode:2023A&A...669A.104K. doi:10.1051/0004-6361/202244283.
  9. ^ "* gam02 Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 22 December 2012.
  10. ^ 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.
  11. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  12. ^ "SIMBAD search". simbad.cds.unistra.fr. Retrieved 2025-06-02.
  13. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.