A-type dwarf; Corona Australis
HD 170384 , also known as HR 6931 or rarely 11 G. Coronae Australis , is a solitary white-hued star located in the southern constellation Corona Australis . It has an apparent magnitude of 6.02,[ 2] making it barely visible to the naked eye , even under ideal conditions. The object is located relatively close at a distance of 229.1 light-years based on Gaia DR3 parallax measurements[ 1] and it is drifting closer with a heliocentric radial velocity of −11.4 km/s .[ 6] At its current distance, HD 170384's brightness is diminished by interstellar extinction of 0.28 magnitudes [ 16] and it has an absolute magnitude of +1.86.[ 7]
This object has a stellar classification of A3 V, indicating that it is an ordinary A-type main-sequence star . It has double the Sun's mass [ 8] and 1.91 times the radius of the Sun .[ 9] It radiates 16.7 times the luminosity of the Sun [ 3] from its photosphere at an effective temperature of 8,694 K .[ 11] HD 170384 has a near solar metallicity at [Fe/H] = −0.01 (97% solar)[ 12] and it is estimated to be 544 million years old,[ 8] having completed 45% of its main sequence lifetime.[ 3] Like many hot stars HD 170384 spins rapidly, having a projected rotational velocity of 127 km/s and an estimated rotation period of 19.2 hours .[ 13]
References
^ a b c d e 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 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 .
^ a b c d Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities" . Astronomy & Astrophysics . 537 : A120. arXiv :1201.2052 . Bibcode :2012A&A...537A.120Z . doi :10.1051/0004-6361/201117691 . eISSN 1432-0746 . ISSN 0004-6361 . S2CID 55586789 .
^ Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars: Declinations −53° to −40° . Vol. 2. Bibcode :1978mcts.book.....H .
^ Corben, P. M. (April 1971). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa . 30 (4): 37. Bibcode :1971MNSSA..30...37C . ISSN 0024-8266 .
^ 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 .
^ a b 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 c d 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 .
^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants" . 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 .
^ 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 . eISSN 1538-3881 . hdl :1721.1/124721 . S2CID 166227927 .
^ a b Balona, L. A. (October 7, 2019). "Evidence for spots on hot stars suggests major revision of stellar physics" . Monthly Notices of the Royal Astronomical Society . 490 (2). Oxford University Press (OUP): 2112– 2116. arXiv :1910.01584 . doi :10.1093/mnras/stz2808 . ISSN 0035-8711 . S2CID 203642124 .
^ a b Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters . 38 (12): 771– 782. arXiv :1606.08814 . Bibcode :2012AstL...38..771G . doi :10.1134/S1063773712120031 . eISSN 1562-6873 . ISSN 1063-7737 . S2CID 118345778 .
^ a b c Reiners, A.; Royer, F. (February 2004). "First signatures of strong differential rotation in A-type stars" . Astronomy & Astrophysics . 415 (1): 325– 329. arXiv :astro-ph/0311341 . Bibcode :2004A&A...415..325R . doi :10.1051/0004-6361:20034175 . eISSN 1432-0746 . ISSN 0004-6361 . S2CID 15726297 .
^ 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 .
^ "HD 170384" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved June 5, 2023 .
^ 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 .