HD 194612 (HR 7812) is a solitary[14] orange hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.9,[2] making it visible to the naked eye under ideal conditions. Parallax measurements place it at a distance of 760 light years[1] and it has a low heliocentric radial velocity of 0.3 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Octans |
| Right ascension | 20h 38m 18.6064s[1] |
| Declination | −81° 17′ 20.6261″[1] |
| Apparent magnitude (V) | 5.89±0.01[2] |
| Characteristics | |
| Evolutionary stage | RGB[3] |
| Spectral type | K5 III[4] |
| U−B color index | +2.02[5] |
| B−V color index | +1.71[5] |
| Astrometry | |
| Radial velocity (Rv) | 0.3±0.4[6] km/s |
| Proper motion (μ) | RA: +1.597 mas/yr[1] Dec.: −37.819 mas/yr[1] |
| Parallax (π) | 4.3006 ± 0.0707 mas[1] |
| Distance | 760 ± 10 ly (233 ± 4 pc) |
| Absolute magnitude (MV) | −0.56[7] |
| Details | |
| Mass | 2.1[8] M☉ |
| Radius | 59.9[9] R☉ |
| Luminosity | 598±13[10] L☉ |
| Surface gravity (log g) | 0.99±0.02[3] cgs |
| Temperature | 3941±122[9] K |
| Rotational velocity (v sin i) | 2.3±1.2[11] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a red giant with a stellar classification of K5 III,[4] and Gaia DR3 stellar evolution models place it on the red giant branch.[3] It has double the mass of the Sun[8] and an enlarged radius of 59.9 R☉[9] due to its evolved status. It shines with a luminosity of 598 L☉[10] from its photosphere at an effective temperature of 3,941 K.[9] Like many giants, HD 194612 has a comparatively modest projected rotational velocity, which is around 2.3 km/s.[11]
References
edit- ^ a b c d e 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.
- ^ a b 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.
- ^ a b c 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.
- ^ a b Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode:1975mcts.book.....H.
- ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
- ^ a b 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 119257644.
- ^ a b Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b c d 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.
- ^ a b 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.
- ^ a b 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: V. Southern stars⋆⋆⋆". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. 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 7812". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 28, 2022.
- ^ Eggleton, P. P.; Tokovinin, A. A. (11 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. eISSN 1365-2966. ISSN 0035-8711.