Gamma Sagittae

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

γ Sagittae
Sagitta constellation map.svg
Red circle.svg
Location of γ Sagittae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagitta
Right ascension 19h 58m 45.42863s[1]
Declination +19° 29′ 31.7281″[1]
Apparent magnitude (V) +3.47[2]
Characteristics
Evolutionary stage Red Giant
Spectral type M0 III[3][4][5]
U−B color index +1.93[2]
B−V color index +1.57[2]
Astrometry
Radial velocity (Rv)−34.0±0.2[6] km/s
Proper motion (μ) RA: 66.21±0.14[1] mas/yr
Dec.: 22.22±0.12[1] mas/yr
Parallax (π)12.62 ± 0.18[1] mas
Distance258 ± 4 ly
(79 ± 1 pc)
Absolute magnitude (MV)−1.11[7]
Details
Mass1.37[8] M
Radius55.13±3.29[9] R
Luminosity (bolometric)562±75[9] L
Surface gravity (log g)1.71[10] cgs
Temperature3,862±40[4] K
Metallicity [Fe/H]−0.14[9] dex
Age2.35[4] Gyr
Other designations
β Sge, 12 Sagittae, BD+19° 4229, FK5 752, GC 27672, HD 189319, HIP 98337, HR 7635, SAO 105500, PPM 137344
Database references
SIMBADdata

Gamma Sagittae, Latinized from γ Sagittae, is the brightest star in northern constellation of Sagitta. A single star,[11] it is visible to the naked eye with an apparent visual magnitude of +3.47.[2] Based upon an annual parallax shift of 12.62 mas as seen from Earth, it is located about 258 light years from the Sun. It is moving closer to the Sun with a radial velocity of −34 km/s.[6]

This is an evolved red giant star with a stellar classification of M0 III.[12] It is around 2.35[4] billion years old with an estimated 1.37[8] times the mass of the Sun and roughly 55[9] times the Sun's radius. The star is radiating about 562[9] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,862 K.[4]

Naming[edit]

In Chinese, 左旗 (Zuǒ Qí), meaning Left Flag, refers to an asterism consisting of γ Sagittae, α Sagittae, β Sagittae, δ Sagittae, ζ Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, γ Sagittae itself is known as 左旗五 (Zuǒ Qí wǔ, English: the Fifth Star of Left Flag.)[13]

References[edit]

  1. ^ a b c d e van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics. 474 (2): 653–64. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D. 
  3. ^ Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. 
  4. ^ a b c d e Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". Astronomical Journal. 150 (3). 88. arXiv:1507.01466Freely accessible. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88. 
  5. ^ Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/mk. Originally published in: Lowell Observatory (October 2014). 1. Bibcode:2014yCat....1.2023S. 
  6. ^ a b Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165. arXiv:astro-ph/0409579Freely accessible. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. 
  7. ^ Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1. 
  8. ^ a b Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas (2015). "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity". Astronomy & Astrophysics. 574: A116. arXiv:1412.4634Freely accessible. Bibcode:2015A&A...574A.116R. doi:10.1051/0004-6361/201322360. 
  9. ^ a b c d e Piau, L.; Kervella, P.; Dib, S.; Hauschildt, P. (2011). "Surface convection and red-giant radius measurements". Astronomy and Astrophysics. 526: 12. arXiv:1010.3649Freely accessible. Bibcode:2011A&A...526A.100P. doi:10.1051/0004-6361/201014442. A100. 
  10. ^ Bluhm, P.; Jones, M. I.; Vanzi, L.; Soto, M. G.; Vos, J.; Wittenmyer, R. A.; Drass, H.; Jenkins, J. S.; Olivares, F.; Mennickent, R. E.; Vučković, M.; Rojo, P.; Melo, C. H. F. (2016). "New spectroscopic binary companions of giant stars and updated metallicity distribution for binary systems". Astronomy & Astrophysics. 593: A133. arXiv:1608.08260Freely accessible. Bibcode:2016A&A...593A.133B. doi:10.1051/0004-6361/201628459. 
  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:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  12. ^ Wittkowski, M.; Hummel, C. A.; Aufdenberg, J. P.; Roccatagliata, V. (December 2006), "Tests of stellar model atmospheres by optical interferometry. III. NPOI and VINCI interferometry of the M0 giant γ Sagittae covering 0.5-2.2 μm", Astronomy and Astrophysics, 460 (3): 843–853, arXiv:astro-ph/0610149Freely accessible, Bibcode:2006A&A...460..843W, doi:10.1051/0004-6361:20065853. 
  13. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日

External links[edit]