Astronomy:HD 204904
Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
---|---|
Constellation | Octans |
Right ascension | 21h 38m 56.38010s[1] |
Declination | −79° 26′ 33.2989″[1] |
Apparent magnitude (V) | 6.17±0.01[2] |
Characteristics | |
Spectral type | F6 IV[3] or F4 IV[4] |
U−B color index | +0.02[5] |
B−V color index | +0.46[5] |
Astrometry | |
Radial velocity (Rv) | −5.2±0.5[6] km/s |
Proper motion (μ) | RA: +71.185[1] mas/yr Dec.: −26.928[1] mas/yr |
Parallax (π) | 15.369 ± 0.0195[1] mas |
Distance | 212.2 ± 0.3 ly (65.07 ± 0.08 pc) |
Absolute magnitude (MV) | +2.13[7] |
Details | |
Mass | 1.53[8] M☉ |
Radius | 2.87±0.15[9] R☉ |
Luminosity | 12.1±0.1[1] L☉ |
Surface gravity (log g) | 3.67+0.10−0.09[10] cgs |
Temperature | 6,443±80[11] K |
Metallicity [Fe/H] | −0.20±0.06[12] dex |
Rotational velocity (v sin i) | 12±1.6[13] km/s |
Age | 2.56[8] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 204904 (HR 8234; 59 G. Octantis) is a spectroscopic binary located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.17,[2] placing it near the limit for naked eye visibility, even under ideal conditions. The object is located relatively close at distance of 212 light-years based on Gaia DR3 parallax measurements[1] and it is drifting closer with a heliocentric radial velocity of −5.2 km/s.[6] At its current distance, HD 204904's brightness is diminished by 0.19 magnitudes due to interstellar extinction[15] and it has an absolute magnitude of +2.13.[7]
HD 204904 has a stellar classification of either F6 IV or F4 IV,[4] indicating that it is a slightly evolved F-type subgiant. It has 1.53 times the mass of the Sun[8] and a slightly enlarged radius 2.87 times that of the Sun's.[9] It radiates 12.1 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 6,443 K,[11] giving it the typical yellowish-white hue of an F-type star. HD 204904 is metal deficient with an iron abundance of [Fe/H] = −0.20 or 63.1% of the Sun's iron abundance.[12] It is estimated to be 2.56 billion years old[8] and it spins modestly with a projected rotational velocity of 12 km/s.[13]
In 2014, J. R. De Medeiros and colleagues detected radial velocity variations from the star, indicating that it was a spectroscopic binary.[13] However, the system does not have a defined orbit.[16]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H.
- ↑ Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars: Declinations −90° to −53°. 1. Bibcode: 1975mcts.book.....H.
- ↑ 4.0 4.1 Malaroda, S. (August 1975). "Study of the F-Type Stars I: MK spectral types.". The Astronomical Journal 80: 637. doi:10.1086/111786. ISSN 0004-6256. Bibcode: 1975AJ.....80..637M.
- ↑ 5.0 5.1 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.
- ↑ 6.0 6.1 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. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode: 2006AstL...32..759G.
- ↑ 7.0 7.1 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A.
- ↑ 8.0 8.1 8.2 8.3 David, Trevor J.; Hillenbrand, Lynne A. (12 May 2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal 804 (2): 146. doi:10.1088/0004-637X/804/2/146. Bibcode: 2015ApJ...804..146D.
- ↑ 9.0 9.1 Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics 426 (1): 297–307. doi:10.1051/0004-6361:20035930. ISSN 0004-6361. Bibcode: 2004A&A...426..297K.
- ↑ Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S.
- ↑ 11.0 11.1 Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.; Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S. (26 May 2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s): Improved astrophysical parameters for the Geneva-Copenhagen Survey⋆". Astronomy & Astrophysics 530: A138. doi:10.1051/0004-6361/201016276. ISSN 0004-6361. Bibcode: 2011A&A...530A.138C.
- ↑ 12.0 12.1 Netopil, Martin (4 May 2017). "Metallicity calibrations for dwarf stars and giants in the Geneva photometric system". Monthly Notices of the Royal Astronomical Society 469 (3): 3042–3055. doi:10.1093/mnras/stx1077. ISSN 0035-8711. Bibcode: 2017MNRAS.469.3042N.
- ↑ 13.0 13.1 13.2 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. doi:10.1051/0004-6361/201220762. ISSN 0004-6361. Bibcode: 2014A&A...561A.126D.
- ↑ "HD 204904". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+204904.
- ↑ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society 472 (4): 3805–3820. doi:10.1093/mnras/stx2219. ISSN 0035-8711. Bibcode: 2017MNRAS.472.3805G.
- ↑ Tokovinin, Andrei (14 March 2014). "From Binaries to Multiples. I. Data on F and G Dwarfs within 67 pc of the Sun". The Astronomical Journal 147 (4): 86. doi:10.1088/0004-6256/147/4/86. ISSN 0004-6256. Bibcode: 2014AJ....147...86T.
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