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HD 201772

Topic: Astronomy

 From HandWiki - Reading time: 6 min

Short description: Star in the constellation Microscopium
HD 201772
HD 201772 is the star circled in red
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Microscopium
Right ascension  21h 13m 03.06827s[1]
Declination −39° 25′ 29.7097″[1]
Apparent magnitude (V) 5.26[2]
Characteristics
Spectral type F5 IV-V[3] or F6 V Fe−0.9 CH−0.5[4]
B−V color index +0.44[2]
Astrometry
Radial velocity (Rv)−41±1[5] km/s
Proper motion (μ) RA: +185.855[1] mas/yr
Dec.: −113.449[1] mas/yr
Parallax (π)29.2823 ± 0.0827[1] mas
Distance111.4 ± 0.3 ly
(34.15 ± 0.10 pc)
Absolute magnitude (MV)+2.66[6]
Details
Mass1.5[1] M☉
Radius2.18±0.09[7] R☉
Luminosity7.83±0.04[1] L☉
Surface gravity (log g)3.91±0.09[8] cgs
Temperature6,519±80[9] K
Metallicity [Fe/H]−0.18±0.03[10] dex
Rotational velocity (v sin i)10[11] km/s
Age2.23±0.04 Gyr
Other designations
CD−39°14152, CPD−39°8898, GC 29640, HD 201772, HIP 104738, HR 8104, SAO 212793, LTT 8413[12]
Database references
SIMBADdata

HD 201772, also known as HR 8104, is a yellowish-white hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.26,[2] making it one of the brighter members of this generally faint constellation. The object is located relatively close at a distance of 111 light-years based on Gaia DR3 parallax measurements[1] but is approaching closer with a heliocentric radial velocity of −41 km/s.[5] At its current distance, HD 201772's brightness is diminished by 0.11 magnitudes due to interstellar dust.[13]

The star has been given multiple stellar classifications over the years. It was given the luminosity class of a subgiant and main sequence star (IV/V; IV-V)[14][3] and a dwarf (V).[15][16] Most sources generally agree that it is a F5 star. Richard O. Gray and colleagues give HD 201772 a class of F6 V Fe−0.9 CH−0.5, which indicates that it is a F-type main-sequence star with an underabundance of iron and CH molecules in its spectrum.[4]

It has 1.47 times the mass of the Sun[17] and an enlarged radius of 2.2 R☉.[7] It radiates 7.8 times the luminosity of the Sun from its photosphere at an effective temperature of 6,519 K.[9] At an age of 2.5 billion years, HD 201722 is currently 1.33 magnitudes above the ZAMS, consistent with a star that is evolving off the main sequence.[11] The star has an iron abundance 66% that of the Sun,[10] making it metal deficient. It spins modestly with a projected rotational velocity of 10 km/s.[11]

HD 201772 is suspected to be a spectroscopic binary consisting of the subgiant described above and an ordinary F6 V star with a mass of 1.31 M☉.[18] However, the stars have no separation or an orbital period.[19] This is because the companion might be a result of spectrum contamination, so HD 201772 is more likely to be a solitary star.[20]

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 Corben, P. M.; Stoy, R. H. (1968). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa 27: 11. ISSN 0024-8266. Bibcode: 1968MNSSA..27...11C. 
  3. ↑ 3.0 3.1 Gray, Richard O. (September 1989). "The extension of the MK spectral classification system to the intermediate population II F type stars". The Astronomical Journal 98: 1049. doi:10.1086/115195. ISSN 0004-6256. Bibcode: 1989AJ.....98.1049G. 
  4. ↑ 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. 
  5. ↑ 5.0 5.1 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. 
  6. ↑ 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. 
  7. ↑ 7.0 7.1 Masana, E.; Jordi, C.; Ribas, I. (10 April 2006). "Effective temperature scale and bolometric corrections from 2MASS photometry". Astronomy & Astrophysics 450 (2): 735–746. doi:10.1051/0004-6361:20054021. ISSN 0004-6361. Bibcode: 2006A&A...450..735M. 
  8. ↑ Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S. 
  9. ↑ 9.0 9.1 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. 
  10. ↑ 10.0 10.1 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. 
  11. ↑ 11.0 11.1 11.2 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. Bibcode: 2004A&A...418..989N. 
  12. ↑ "HD 201772". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+201772. 
  13. ↑ 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. 
  14. ↑ Adams, Walter S.; Joy, Alfred H.; Humason, Milton L.; Brayton, Ada Margaret (April 1935). "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars". The Astrophysical Journal 81: 187. doi:10.1086/143628. ISSN 0004-637X. Bibcode: 1935ApJ....81..187A. 
  15. ↑ Malaroda, S. (August 1975). "Study of the F-type 1 MK spectral types.". The Astronomical Journal 80: 637. doi:10.1086/111786. ISSN 0004-6256. Bibcode: 1975AJ.....80..637M. 
  16. ↑ Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume III: Declinations −40° to −26°. Bibcode: 1982mcts.book.....H. 
  17. ↑ Feltzing, S.; Holmberg, J.; Hurley, J. R. (October 2001). "The solar neighbourhood age-metallicity relation - Does it exist?". Astronomy & Astrophysics 377 (3): 911–924. doi:10.1051/0004-6361:20011119. ISSN 0004-6361. Bibcode: 2001A&A...377..911F. 
  18. ↑ Tokovinin, Andrei (14 March 2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal 147 (4): 87. doi:10.1088/0004-6256/147/4/87. ISSN 0004-6256. Bibcode: 2014AJ....147...87T. 
  19. ↑ Tokovinin, Andrei (14 March 2014). "From Binaries to Multiples. I. Data on F and G Dwarfs within 67 pc of the Sun". The Astronomical Journal 147 (4): 86. doi:10.1088/0004-6256/147/4/86. ISSN 0004-6256. Bibcode: 2014AJ....147...86T. 
  20. ↑ 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. Bibcode: 2008MNRAS.389..869E. 
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