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Eta1 Coronae Australis 
Summary
Eta1 Coronae Australis, Latinized from η1 CrA, is a suspected astrometric binary[11] star system in the constellation of Corona Australis. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.456.[2] Parallax measurements put it at a distance of 317 light-years away from the Sun.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 48m 50.49216s[1] |
| Declination | −43° 40′ 48.1977″[1] |
| Apparent magnitude (V) | 5.456[2] |
| Characteristics | |
| Spectral type | A3V[3] |
| B−V color index | +0.13[4] |
| Astrometry | |
| Radial velocity (Rv) | −4.0±4.2[5] km/s |
| Proper motion (μ) | RA: 22.312[1] mas/yr Dec.: −14.139[1] mas/yr |
| Parallax (π) | 10.2735 ± 0.1889 mas[1] |
| Distance | 317 ± 6 ly (97 ± 2 pc) |
| Absolute magnitude (MV) | 0.84[6] |
| Details | |
| Radius | 2.2[7] R☉ |
| Luminosity | 57.72[8] L☉ |
| Surface gravity (log g) | 4.04[6] cgs |
| Temperature | 8371+4692 −444[9] K |
| Rotational velocity (v sin i) | 122.3[10] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
The visible component is an A-type main-sequence star with a stellar classification of A3V,[3] which indicates it is generating energy through core hydrogen fusion. It has broad spectrum absorption lines associated with its rotation period, having a projected rotational velocity of 122.3 km/s.[10] The star is radiating 58[8] times the luminosity of the Sun from its photosphere at an effective temperature of 8,371 K.[9]
References edit
- ^ a b c d e 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 Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ a b Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 2. Ann Arbor: Dept. of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
- ^ Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
- ^ Gontcharov, G. A. (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. S2CID 119231169.
- ^ a b Philip, A. Davis; Egret, D. (1980). "An Analysis of the Hauck / Mermilliod Catalogue of Homgeneous Four-Color Data - Part Two". Astronomy and Astrophysics Supplement. 40: 199. Bibcode:1980A&AS...40..199P.
- ^ Pasinetti Fracassini, L. E.; et al. (February 2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics". Astronomy and Astrophysics. 367 (2): 521–524. arXiv:astro-ph/0012289. Bibcode:2001A&A...367..521P. doi:10.1051/0004-6361:20000451. S2CID 425754.
- ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Ammons, S. Mark; Robinson, Sarah E.; Strader, Jay; Laughlin, Gregory; Fischer, Debra; Wolf, Aaron (2006). "The N2K Consortium. IV. New Temperatures and Metallicities for More than 100,000 FGK Dwarfs". The Astrophysical Journal. 638 (2): 1004–1017. arXiv:astro-ph/0510237. Bibcode:2006ApJ...638.1004A. doi:10.1086/498490. S2CID 118834752.
- ^ a b Díaz, C. G.; González, J. F.; Levato, H.; Grosso, M. (2011). "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum". Astronomy & Astrophysics. 531: A143. arXiv:1012.4858. Bibcode:2011A&A...531A.143D. doi:10.1051/0004-6361/201016386. S2CID 119286673.
- ^ Eggleton, P. P.; Tokovinin, A. A. (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, S2CID 14878976.