Eta Sagittae
  | |
| Observation data EpochJ2000.0EquinoxJ2000.0(ICRS) | |
|---|---|
| Constellation | Sagitta |
| Right ascension | 20h05m09.49303s[1] |
| Declination | +19° 59′ 27.8575″[1] |
| Apparent magnitude(V) | +5.09[2] |
| Characteristics | |
| Spectral type | K2 III[3] |
| U−Bcolor index | +0.98[2] |
| B−Vcolor index | +1.06[2] |
| Astrometry | |
| Radial velocity(Rv) | −40.53[4]km/s |
| Proper motion(μ) | RA:+29.962±0.173[4]mas/yr Dec.:+80.440±0.173[4]mas/yr |
| Parallax(π) | 20.9262 ± 0.1208mas[4] |
| Distance | 155.9 ± 0.9ly (47.8 ± 0.3pc) |
| Absolute magnitude(MV) | 1.61[5] |
| Details[6] | |
| Mass | 1.73±0.09M☉ |
| Radius | 7.08±0.21R☉ |
| Luminosity | 26L☉ |
| Surface gravity(logg) | 3.03±0.10cgs |
| Temperature | 4,784±3.03K |
| Metallicity[Fe/H] | +0.10dex |
| Rotational velocity(vsini) | 1.3[5]km/s |
| Age | 1.69±0.25Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Eta Sagittae(η Sagittae) is solitary[8]starin the northernconstellationofSagitta.It is faintly visible to the naked eye, having anapparent visual magnitudeof +5.09.[2]Based upon an annualparallaxshift of20.34mas,[1]it is approximately160light yearsdistant from theSun.There is a 61.1% chance that it is a member of theHyades-Pleiadesstream of stars that share acommon motion through space.[9]
This is anevolvedK-typegiant starwith astellar classificationof K2 III.[3]At the age of about 1.7 billion years,[6]it is now ared clumpstar that is generating energy through the fusion of helium at its core.[10]Eta Sagittae has 1.7 times themass of the Sunand has expanded to seven times theSun's radius.It is radiating 25.7 times theSun's luminosityfrom itsphotosphereat aneffective temperatureof4,784K.[6]
References
[edit]- ^abcvan 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,S2CID18759600.
- ^abcdArgue, A. N. (1966), "UBV photometry of 550 F, G and K type stars",Monthly Notices of the Royal Astronomical Society,133(4): 475–493,Bibcode:1966MNRAS.133..475A,doi:10.1093/mnras/133.4.475.
- ^abRoman, Nancy G. (July 1952), "The Spectra of the Bright Stars of Types F5-K5",Astrophysical Journal,116:122,Bibcode:1952ApJ...116..122R,doi:10.1086/145598.
- ^abcdBrown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
- ^abSetiawan, 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.
- ^abcMaldonado, J.; et al. (June 2013), "The metallicity signature of evolved stars with planets",Astronomy & Astrophysics,554:18,arXiv:1303.3418,Bibcode:2013A&A...554A..84M,doi:10.1051/0004-6361/201321082,S2CID119289111,A84.
- ^"eta Sge".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved2017-07-11.
{{cite web}}:CS1 maint: postscript (link) - ^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,S2CID14878976.
- ^Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters",Astronomy and Astrophysics,430:165–186,arXiv:astro-ph/0409579,Bibcode:2005A&A...430..165F,doi:10.1051/0004-6361:20041272,S2CID17804304.
- ^Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity",The Astrophysical Journal,539(2): 732–741,arXiv:astro-ph/0003329,Bibcode:2000ApJ...539..732A,doi:10.1086/309278,S2CID16673121.
