Astronomy:HD 170773
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| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 33m 00.91673s[1] |
| Declination | −39° 53′ 31.2751″[1] |
| Apparent magnitude (V) | 6.22±0.01[2] |
| Characteristics | |
| Spectral type | F5 V[3][4] |
| B−V color index | +0.42[5] |
| Astrometry | |
| Radial velocity (Rv) | −25.2±1.0[6] km/s |
| Proper motion (μ) | RA: +86.353[1] mas/yr Dec.: −79.927[1] mas/yr |
| Parallax (π) | 27.0749 ± 0.03[1] mas |
| Distance | 120.5 ± 0.1 ly (36.93 ± 0.04 pc) |
| Absolute magnitude (MV) | +3.38[7] |
| Details | |
| Mass | 1.30[8] M☉ |
| Radius | 1.43±0.07[9] R☉ |
| Luminosity | 3.62±0.01[1] L☉ |
| Surface gravity (log g) | 4.21±0.04[10] cgs |
| Temperature | 6,694±126[11] K |
| Metallicity [Fe/H] | −0.02±0.04[12] dex |
| Rotational velocity (v sin i) | 67.2±6.2[13] km/s |
| Age | 1.50+1.2−0.7[10] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 170773 (HR 6948; 14 G. Coronae Australis) is a solitary star located in the southern constellation Corona Australis. It has an apparent magnitude of 6.22,[2] placing it near the limit for naked eye visibility, even under ideal conditions. The object is located relatively close at a distance of 120 light-years based on Gaia DR3 parallax measurements[1] and it is drifting closer with a heliocentric radial velocity of −25.2 km/s.[6] At its current distance, HD 170773's brightness is diminished by an interstellar extinction of 0.19 magnitudes[14] and it has an absolute magnitude of +3.38.[7]
HD 170773 has a stellar classification of F5 V,[3][4] indicating that it is an ordinary F-type main-sequence star that is generating energy via hydrogen fusion at its core. It has also been given a classification of F5 IV, indicating that it is a slightly evolved subgiant that is ceasing hydrogen fusion at its core. It has 1.30 times the mass of the Sun[8] and 1.43 times the radius of the Sun.[9] It radiates 3.62 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 6,694 K,[11] giving it the typical yellowish-white hue of a F-type star. HD 170773 has a near solar metallicity of [Fe/H] = −0.02[12] and it is estimated to be 1.5 billion years old.[10] It spins fairly quickly with a projected rotational velocity of 67.2 km/s.[13]
The star has a debris disk located 78 astronomical unit|AU away and it has a temperature of 43 K.[15] It was first observed in 1986 by astronomers K. Sakadane and M. Nishida in their survey of Vega-like stars due to the star displaying an infrared excess that could suggest the presence of a circumstellar disk.[16] However, the actual disk was not discovered until 2004 using the Spitzer Space Telescope.[17] There might be a second cooler disk surrounding the star, but subsequent observations have not confirmed this.[15]
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.
- ↑ 3.0 3.1 Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Declinations −40° to −26°. 3. Bibcode: 1982mcts.book.....H.
- ↑ 4.0 4.1 Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2 June 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. ISSN 0004-6256. Bibcode: 2006AJ....132..161G.
- ↑ Corben, P. M. (1966). "Photoelectric magnitudes and colours for bright southern stars". Monthly Notes of the Astronomical Society of South Africa 25: 44. ISSN 0024-8266. Bibcode: 1966MNSSA..25...44C.
- ↑ 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 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.
- ↑ 10.0 10.1 10.2 Sepulveda, Aldo G.; Matrà, Luca; Kennedy, Grant M.; Burgo, Carlos del; Öberg, Karin I.; Wilner, David J.; Marino, Sebastián; Booth, Mark et al. (August 14, 2019). "The REASONS Survey: Resolved Millimeter Observations of a Large Debris Disk around the Nearby F Star HD 170773". The Astrophysical Journal 881 (1): 84. doi:10.3847/1538-4357/ab2b98. ISSN 1538-4357. Bibcode: 2019ApJ...881...84S.
- ↑ 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 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.
- ↑ 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.
- ↑ 15.0 15.1 Moór, A.; Pascucci, I.; Kóspál, á.; Ábrahám, P.; Csengeri, T.; Kiss, L. L.; Apai, D.; Grady, C. et al. (March 2011). "Structure and Evolution of Debris Disks Around F-type Stars. I. Observations, Database, and Basic Evolutionary Aspects". The Astrophysical Journal Supplement Series 193 (1): 4. doi:10.1088/0067-0049/193/1/4. ISSN 0067-0049. Bibcode: 2011ApJS..193....4M.
- ↑ Sadakane, K.; Nishida, M. (July 1986). "Twelve additional 'Vega-like' stars". Publications of the Astronomical Society of the Pacific 98: 685. doi:10.1086/131813. ISSN 0004-6280. Bibcode: 1986PASP...98..685S.
- ↑ Zuckerman, B.; Song, Inseok (March 10, 2004). "Dusty Debris Disks as Signposts of Planets: Implications for Spitzer Space Telescope". The Astrophysical Journal 603 (2): 738–743. doi:10.1086/381700. ISSN 0004-637X. Bibcode: 2004ApJ...603..738Z.
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