Astronomy:HD 171819

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Short description: Star in the constellation Telescopium
HD 171819
Location of HD 171819 (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Telescopium
Right ascension  18h 39m 14.29289s[1]
Declination −47° 54′ 35.1520″[1]
Apparent magnitude (V) 5.84±0.01[2]
Characteristics
Spectral type A7 IV/V[3] or A3 V[4]
B−V color index +0.23[5]
Astrometry
Radial velocity (Rv)−9±4.3[6] km/s
Proper motion (μ) RA: +25.426[1] mas/yr
Dec.: +13.951[1] mas/yr
Parallax (π)10.4348 ± 0.1045[1] mas
Distance313 ± 3 ly
(95.8 ± 1.0 pc)
Absolute magnitude (MV)+0.65[7]
Details
Mass1.73+0.37−0.19[8] M☉
Radius3.37±0.17[9] R☉
Luminosity33.3±0.1[1] L☉
Surface gravity (log g)3.60±0.08[8] cgs
Temperature7,512[10] K
Metallicity [Fe/H]−0.02[11] dex
Age855[1] Myr
Other designations
CD−48°12644, CPD−48°9900, FK5 3482, GC 25474, HD 171819, HIP 91461, HR 6986, SAO 229165[12]
Database references
SIMBADdata

HD 171819, also known as HR 6986 or rarely 22 G. Telescopii, is a solitary star[13] located in the southern constellation Telescopium. It is faintly visible to the naked eye as a white-hued object with an apparent magnitude of 5.84.[2] The object is located relatively close at a distance of 313 light years based on Gaia DR3 parallax measurements, but it is approaching the Solar System with a heliocentric radial velocity of −9 km/s.[6] At its current distance, HD 171819's brightness is diminished by one-quarter of a magnitude due to interstellar dust[14] and it has an absolute magnitude of +0.65.[7]

HD 171819 has a stellar classification of A7 IV/V, indicating that the object is a late A-type star with the blended luminosity class of a main sequence star and subgiant.[3] However, astronomer William Buscombe gave it a class of A3 V,[4] instead making it an ordinary A-type main-sequence star. Evolutionary models give it an age of 855 million years and place it towards the end of its main-sequence life.[1] At present it has 1.73 times the mass of the Sun[8] and a slightly enlarged radius 3.37 times that of the Sun.[9] It radiates 33.3 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 7,512 K.[10] HD 171819 has a near solar metallicity at [Fe/H] = −0.02.[11]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 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 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. Bibcode: 2000A&A...355L..27H. 
  3. ↑ 3.0 3.1 Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars: Declinations −53° to −40°. 2. Bibcode: 1978mcts.book.....H. 
  4. ↑ 4.0 4.1 Buscombe, W. (1 May 1969). "Line Strengths for Southern OB stars--II: Observations with Moderate Dispersion". Monthly Notices of the Royal Astronomical Society 144 (1): 31–39. doi:10.1093/mnras/144.1.31. ISSN 0035-8711. Bibcode: 1969MNRAS.144...31B. 
  5. ↑ Stoy, R. H. (1968). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa 27: 119. ISSN 0024-8266. Bibcode: 1968MNSSA..27..119S. 
  6. ↑ 6.0 6.1 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. 
  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. Bibcode: 2012AstL...38..331A. 
  8. ↑ 8.0 8.1 8.2 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 Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants. Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics 426 (1): 297–307. doi:10.1051/0004-6361:20035930. ISSN 0004-6361. Bibcode: 2004A&A...426..297K. 
  10. ↑ 10.0 10.1 Stassun, Keivan G.; Oelkers, Ryan J.; Pepper, Joshua et al. (20 August 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal 156 (3): 102. doi:10.3847/1538-3881/aad050. Bibcode: 2018AJ....156..102S. 
  11. ↑ 11.0 11.1 Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. ISSN 1063-7737. Bibcode: 2012AstL...38..771G. 
  12. ↑ "HD 171819". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+171819. 
  13. ↑ 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. 
  14. ↑ 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. 
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