HD 173791
HD 173791 (HR 7065) is a solitary[14] yellow hued star located in the southern constellation Telescopium. It has an apparent magnitude of 5.80,[2] allowing it to be viewed with the naked eye under suitable viewing conditions. Parallax measurements place the object at a distance of 364 light years ,[1] and it is currently receding from the Solar System with a heliocentric radial velocity of 9.7 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)  | |
|---|---|
| Constellation | Telescopium | 
| Right ascension | 18h 49m 27.3433s[1] | 
| Declination | –45° 48′ 36.3601″[1] | 
| Apparent magnitude (V) | 5.80 ± 0.01[2] | 
| Characteristics | |
| Evolutionary stage | Horizontal branch[3] | 
| Spectral type | G8 III[4] | 
| B−V color index | +0.9[5] | 
| Astrometry | |
| Radial velocity (Rv) | 9.7 ± 2.9[6] km/s | 
| Proper motion (μ) |  RA: +74.263[1] mas/yr  Dec.: +57.015[1] mas/yr  | 
| Parallax (π) | 8.9671 ± 0.0429 mas[1] | 
| Distance | 364 ± 2 ly  (111.5 ± 0.5 pc)  | 
| Absolute magnitude (MV) | +0.6[7] | 
| Details | |
| Mass | 1.31[8] M☉ | 
| Radius | 10.3[9] R☉ | 
| Luminosity | 63.6±0.9[10] L☉ | 
| Surface gravity (log g) | 2.46[8] cgs | 
| Temperature | 5,093±123[9] K | 
| Metallicity [Fe/H] | −0.43 ± 0.16[3] dex | 
| Rotational velocity (v sin i) | 2.7±1.5[11] km/s | 
| Other designations | |
| Database references | |
| SIMBAD | data | 
This is a red giant with a stellar classification of G8 III.[4] It is currently on the cool end of the horizontal branch, fusing helium at its core.[3] At present it has 1.31 times the mass of the Sun[8] but has expanded to 10.3 times its girth.[9] It radiates at 63.6 L☉[10] from its enlarged photosphere at an effective temperature of 5,093 K.[9] HD 173791 is metal deficient–with a metallicity only 37% that of the Sun;[3] it spins modestly with a projected rotational velocity of 2.7 km/s.[3]
References
    
- Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
 - Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
 - Jones, M. I.; Jenkins, J. S.; Rojo, P.; Melo, C. H. F. (December 2011). "Study of the impact of the post-MS evolution of the host star on the orbits of close-in planets: I. Sample definition and physical properties⋆⋆⋆". Astronomy & Astrophysics. 536: A71. arXiv:1110.6459. Bibcode:2011A&A...536A..71J. doi:10.1051/0004-6361/201117887. ISSN 0004-6361.
 - Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. Bibcode:1978mcts.book.....H.
 - Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1 January 1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
 - Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
 - Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 255204555.
 - Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. eISSN 1432-0746. ISSN 0004-6361.
 - Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256.
 - Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data 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 source at VizieR.
 - De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. eISSN 1432-0746. ISSN 0004-6361.
 - Gould, B. A., Uranometria Argentina, Reprinted and updated by Pilcher, F, archived from the original on 2012-02-27, retrieved 2012-01-06
 - "HR 7065 -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-19
 - 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