Astronomy:V701 Coronae Australis

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Short description: Delta Scuti variable; Corona Australis
V701 Coronae Australis
Corona Australis constellation map.svg
Red circle.svg
Location of HD 168592 (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Corona Australis
Right ascension  19h 03m 17.69619s[1]
Declination −38° 15′ 11.3335″[1]
Apparent magnitude (V) 5.69 to 5.73[2]
Characteristics
Spectral type F2 III/IV[3] or F0 IIIn[4]
B−V color index +0.32[5]
Variable type δ Scuti[2]
Astrometry
Radial velocity (Rv)4±7.4[6] km/s
Proper motion (μ) RA: +12.794[1] mas/yr
Dec.: +14.271[1] mas/yr
Parallax (π)15.2952 ± 0.0559[1] mas
Distance213.2 ± 0.8 ly
(65.4 ± 0.2 pc)
Absolute magnitude (MV)+1.55[7]
Details
Mass1.83+0.07−0.06[8] M
Radius2.85±0.14[9] R
Luminosity17.5+0.2−0.1[1] L
Surface gravity (log g)3.75±0.12[10] cgs
Temperature7,046±240[11] K
Metallicity [Fe/H]−0.21[12] dex
Rotational velocity (v sin i)265[13] km/s
Age1.25[11] Gyr
Other designations
V701 CrA, CD−38°13300, CPD−38°7685, GC 26177, HD 176723, HIP 93552, HR 7197, SAO 210859[14]
Database references
SIMBADdata

V701 Coronae Australis (HD 176723; HR 7197; 40 G. Coronae Australis), or simply V701 CrA, is a solitary,[15] yellowish-white hued variable star located in the southern constellation Corona Australis. It has an average apparent magnitude of 5.72,[16] making it faintly visible to the naked eye under ideal conditions. The object is located relatively close at a distance of 213 light-years based on Gaia DR3 parallax measurements,[1] and it is currently receding with a poorly constrained heliocentric radial velocity of km/s.[6] At its current distance, V701 CrA's brightness is diminished by a quarter of a magnitude due to extinction[17] and it has an absolute magnitude of +1.55.[7]

A light curve for V701 Coronae Australis, plotted from TESS data[18]

The object was first suspected to be variable in 1990. The variations matched that of δ Scuti variables.[19] Three years later, it was confirmed to be variable and was given the variable star designation V701 Coronae Australis.[20] It ranges from magnitude 5.69 to 5.73[2] within 3.25 hours.[21]

V701 CrA has a stellar classification of F2 III/IV,[3] indicating that it is an evolved F-type star with the blended luminosity class of a subgiant and giant star. It has also been given a class of F0 IIIn,[4] indicating broad or nebulous absorption lines due to rapid rotation. It has 1.83 times the mass of the Sun[8] and a slightly enlarged radius of 2.85 R.[9] It radiates 17.5 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 7,046 K.[11] The star spins rapidly with a projected rotational velocity of 265 km/s,[13] which causes it to have an equatorial bulge that is 26% larger than the poles.[22] It is metal deficient with an iron abundance 62% that of the Sun ([Fe/H] = −0.21)[12] and it is estimated to be 1.25 billion years old.[11] V701 CrA was considered to be a chemically peculiar star and was given a class of FpSr. Its peculiarity is now considered to be doubtful.[23]

References

  1. 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. 2.0 2.1 2.2 Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports 61 (1): 80–88. doi:10.1134/S1063772917010085. ISSN 1063-7729. Bibcode2017ARep...61...80S. 
  3. 3.0 3.1 Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Declinations −40° to −26°. 3. Bibcode1982mcts.book.....H. 
  4. 4.0 4.1 Evans, D. S.; Laing, J. D.; Menzies, A.; Stoy, R. H. (1964). "Fundamental data for southern stars (fifth list)". Royal Greenwich Observatory Bulletins 85: 207–224. Bibcode1964RGOB...85..207E. 
  5. 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. Bibcode1966CoLPL...4...99J. 
  6. 6.0 6.1 Holmberg, J.; Nordström, B.; Andersen, J. (6 August 2007). "The Geneva-Copenhagen survey of the Solar neighbourhood II". Astronomy & Astrophysics 475 (2): 519–537. doi:10.1051/0004-6361:20077221. ISSN 0004-6361. Bibcode2007A&A...475..519H. 
  7. 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. Bibcode2012AstL...38..331A. 
  8. 8.0 8.1 Nordström, B.; Mayor, M.; Andersen, J.; Holmberg, J.; Pont, F.; Jørgensen, B. R.; Olsen, E. H.; Udry, S. et al. (16 April 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood". Astronomy & Astrophysics 418 (3): 989–1019. doi:10.1051/0004-6361:20035959. ISSN 0004-6361. Bibcode2004A&A...418..989N. 
  9. 9.0 9.1 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. doi:10.1051/0004-6361:20035930. ISSN 0004-6361. Bibcode2004A&A...426..297K. 
  10. Allende Prieto, C.; Lambert, D. L. (December 1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics 352: 555–562. ISSN 0004-6361. Bibcode1999A&A...352..555A. 
  11. 11.0 11.1 11.2 11.3 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. Bibcode2015ApJ...804..146D. 
  12. 12.0 12.1 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. Bibcode2011A&A...530A.138C. 
  13. 13.0 13.1 Huang, Su-Shu (September 1953). "A Statistical Study of the Rotation of the Stars.". The Astrophysical Journal 118: 285. doi:10.1086/145751. ISSN 0004-637X. Bibcode1953ApJ...118..285H. 
  14. "V* V701 Coronae Australis". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+V701+Coronae+Australis. 
  15. Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. Bibcode2008MNRAS.389..869E. 
  16. 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. Bibcode2000A&A...355L..27H. 
  17. 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. Bibcode2017MNRAS.472.3805G. 
  18. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  19. Lampens, P.; Rufener, F. (April 1990). "Study of delta Scuti stars in the Geneva photometric system. I. New photometric data and period analysis for nine stars.". Astronomy and Astrophysics Supplement Series 83: 145–182. ISSN 0365-0138. Bibcode1990A&AS...83..145L. 
  20. Kazarovets, E. V.; Samus, N. N.; Goranskij, V. P. (February 1993). "The 71st Name-List of Variable Stars". Information Bulletin on Variable Stars 3840: 1. ISSN 0374-0676. Bibcode1993IBVS.3840....1K. 
  21. Rodriguez, E.; Lopez de Coca, P.; Rolland, A.; Garrido, R.; Costa, V. (July 1994). "δ Scuti stars: a new revised list". Astronomy and Astrophysics Supplement Series 106: 21–28. ISSN 0365-0138. Bibcode1994A&AS..106...21R. 
  22. van Belle, Gerard T. (14 March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review 20 (1): 51. doi:10.1007/s00159-012-0051-2. ISSN 0935-4956. Bibcode2012A&ARv..20...51V. 
  23. Renson, P.; Manfroid, J. (19 March 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy & Astrophysics 498 (3): 961–966. doi:10.1051/0004-6361/200810788. ISSN 0004-6361. Bibcode2009A&A...498..961R. 
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