Astronomy:HD 171819

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Short description: Star in the constellation Telescopium
HD 171819
Telescopium constellation map.svg
Red circle.svg
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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