HD 170773

Last updated
HD 170773
The 74 exocomet belts imaged by ALMA's REASONS survey, showing belts of all shapes, sizes and ages (REASONS comboplot full nonames).jpg
Image of the disk with the REASONS survey [1]
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Corona Australis
Right ascension 18h 33m 00.91673s [2]
Declination −39° 53′ 31.2751″ [2]
Apparent magnitude  (V)6.22±0.01 [3]
Characteristics
Spectral type F5 V [4] [5]
B−V color index +0.42 [6]
Astrometry
Radial velocity (Rv)−25.2±1.0 [7] km/s
Proper motion (μ)RA: +86.353 mas/yr [2]
Dec.: −79.927 mas/yr [2]
Parallax (π)27.0749±0.03  mas [2]
Distance 120.5 ± 0.1  ly
(36.93 ± 0.04  pc)
Absolute magnitude  (MV)+3.38 [8]
Details
Mass 1.30 [9]   M☉
Radius 1.43±0.07 [10]   R☉
Luminosity 3.62±0.01 [2]   L☉
Surface gravity (log g)4.21±0.04 [11]   cgs
Temperature 6,694±126 [12]   K
Metallicity [Fe/H]−0.02±0.04 [13]   dex
Rotational velocity (v sin i)67.2±6.2 [14]  km/s
Age 1.50+1.2
−0.7 [11]   Gyr
Other designations
14 G. Coronae Australis [15] , CD−39°12704, CPD−39°8118, FK5 3470, GC 25304, HD 170773, HIP 90936, HR 6948, SAO 210286, TIC 313723578
Corona Australis constellation map.svg
Red circle.svg
Location of HD 170773 on the map (circled)
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, [3] 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 [2] and it is drifting closer with a heliocentric radial velocity of −25.2  km/s . [7] At its current distance, HD 170773's brightness is diminished by an interstellar extinction of 0.19 magnitudes [16] and it has an absolute magnitude of +3.38. [8]

HD 170773 has a stellar classification of F5 V, [4] [5] 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 [9] and 1.43 times the radius of the Sun. [10] It radiates 3.62 times the luminosity of the Sun [2] from its photosphere at an effective temperature of 6,694  K , [12] giving it the typical yellowish-white hue of a F-type star. HD 170773 has a near solar metallicity of [Fe/H] = −0.02 [13] and it is estimated to be 1.5 billion years old. [11] It spins fairly quickly with a projected rotational velocity of 67.2  km/s . [14]

The star has a debris disk located 78  AU away and it has a temperature of 43 K. [17] 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. [18] However, the actual disk was not discovered until 2004 using the Spitzer Space Telescope. [19] There might be a second cooler disk surrounding the star, but subsequent observations have not confirmed this. [17]

References

  1. ↑ Matrà, L.; Marino, S.; Wilner, D. J.; Kennedy, G. M.; Booth, M.; Krivov, A. V.; Williams, J. P.; Hughes, A. M.; Burgo, C. del (2025-01-15). "REsolved ALMA and SMA Observations of Nearby Stars (REASONS): A population of 74 resolved planetesimal belts at millimetre wavelengths". Astronomy and Astrophysics. 693. arXiv: 2501.09058 . Bibcode:2025A&A...693A.151M. doi:10.1051/0004-6361/202451397.
  2. 1 2 3 4 5 6 7 8 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.
  3. 1 2 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. S2CID   17128864.
  4. 1 2 Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Declinations −40° to −26°. Vol. 3. Bibcode:1982mcts.book.....H.
  5. 1 2 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. arXiv: astro-ph/0603770 . Bibcode:2006AJ....132..161G. doi: 10.1086/504637 . eISSN   1538-3881. ISSN   0004-6256. S2CID   250741593.
  6. ↑ Corben, P. M. (1966). "Photoelectric magnitudes and colours for bright southern stars". Monthly Notes of the Astronomical Society of South Africa. 25: 44. Bibcode:1966MNSSA..25...44C. ISSN   0024-8266.
  7. 1 2 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.
  8. 1 2 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.
  9. 1 2 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. arXiv: 1501.03154 . Bibcode:2015ApJ...804..146D. doi: 10.1088/0004-637X/804/2/146 . eISSN   1538-4357. S2CID   33401607.
  10. 1 2 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. arXiv: astro-ph/0404180 . Bibcode:2004A&A...426..297K. doi: 10.1051/0004-6361:20035930 . eISSN   1432-0746. ISSN   0004-6361. S2CID   6077801.
  11. 1 2 3 Sepulveda, Aldo G.; Matrà, Luca; Kennedy, Grant M.; Burgo, Carlos del; Öberg, Karin I.; Wilner, David J.; Marino, Sebastián; Booth, Mark; Carpenter, John M.; Davies, Claire L.; Dent, William R. F.; Ertel, Steve; Lestrade, Jean-Francois; Marshall, Jonathan P.; Milli, Julien; Wyatt, Mark C.; MacGregor, Meredith A.; Matthews, Brenda C. (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. arXiv: 1906.08797 . Bibcode:2019ApJ...881...84S. doi: 10.3847/1538-4357/ab2b98 . ISSN   1538-4357. S2CID   195316295.
  12. 1 2 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. arXiv: 1103.4651 . Bibcode:2011A&A...530A.138C. doi: 10.1051/0004-6361/201016276 . eISSN   1432-0746. ISSN   0004-6361. S2CID   56118016.
  13. 1 2 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. arXiv: 1705.00883 . Bibcode:2017MNRAS.469.3042N. doi: 10.1093/mnras/stx1077 . eISSN   1365-2966. ISSN   0035-8711. S2CID   119034918.
  14. 1 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. arXiv: 1312.3474 . Bibcode:2014A&A...561A.126D. doi: 10.1051/0004-6361/201220762 . eISSN   1432-0746. ISSN   0004-6361. S2CID   54046583.
  15. ↑ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  16. ↑ 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. arXiv: 1709.01160 . Bibcode:2017MNRAS.472.3805G. doi: 10.1093/mnras/stx2219 . eISSN   1365-2966. ISSN   0035-8711. S2CID   118879856.
  17. 1 2 Moór, A.; Pascucci, I.; Kóspál, á.; Ábrahám, P.; Csengeri, T.; Kiss, L. L.; Apai, D.; Grady, C.; Henning, Th.; Kiss, Cs.; Bayliss, D.; Juhász, A.; Kovács, J.; Szalai, T. (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. arXiv: 1012.3631 . Bibcode:2011ApJS..193....4M. doi: 10.1088/0067-0049/193/1/4 . ISSN   0067-0049. S2CID   119243287.
  18. ↑ Sadakane, K.; Nishida, M. (July 1986). "Twelve additional 'Vega-like' stars". Publications of the Astronomical Society of the Pacific. 98: 685. Bibcode:1986PASP...98..685S. doi: 10.1086/131813 . ISSN   0004-6280. S2CID   120682699.
  19. ↑ 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. arXiv: astro-ph/0311546 . Bibcode:2004ApJ...603..738Z. doi: 10.1086/381700 . ISSN   0004-637X. S2CID   3456817.
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