Astronomy:HD 170069

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Short description: Star in the constellation Telescopium
HD 170069
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Telescopium
Right ascension  18h 29m 55.9414s[1]
Declination −47° 13′ 13.9500″[1]
Apparent magnitude (V) 5.68±0.01[2]
Characteristics
Spectral type K2 III[3]
B−V color index +1.26[4]
Astrometry
Radial velocity (Rv)−18±4.3[5] km/s
Proper motion (μ) RA: +28.685[1] mas/yr
Dec.: −12.434[1] mas/yr
Parallax (π)5.5748 ± 0.1894[1] mas
Distance590 ± 20 ly
(179 ± 6 pc)
Absolute magnitude (MV)−0.78[6]
Details
Mass4.08[7] M
Radius23.69[8] R
Luminosity217[9] L
Surface gravity (log g)1.46[10] cgs
Temperature4490±125[8] K
Rotational velocity (v sin i)<1[11] km/s
Other designations
CD−47°12319, CPD−47°8894, GC 25216, HD 170069, HIP 90662, HR 6922, SAO 229064[12][13]
Database references
SIMBADdata

HD 170069 (HR 6922) is a solitary[14] star in the southern constellation Telescopium. It has an apparent magnitude of 5.68,[2] allowing it to be faintly seen with the naked eye. The star is located at a distance of 590 light years[1] but is approaching closer with a heliocentric radial velocity of −18 km/s.[5] HD 170069 was designated as Tau Telescopii (τ Telescopii) before Benjamin Apthorp Gould dropped the title.[15]

HD 170069 has a stellar classification of K2 III,[3] indicating that it is a red giant. It has 4.08 times the mass of the Sun[7] but has expanded to 23.69 times its girth.[8] It radiates at 217 times the luminosity of the Sun[9] from its enlarged photosphere at an effective temperature of 4,490 K,[8] giving an orange hue. Due to its evolved state, it has a projected rotational velocity that is less than km/s.[11]

References

  1. 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 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. Bibcode2000A&A...355L..27H. 
  3. 3.0 3.1 Houk, Nancy (1978). "Michigan catalogue of two-dimensional spectral types for the HD stars". Ann Arbor: Dept. Of Astronomy. Bibcode1978mcts.book.....H. 
  4. Corben, P. M. (April 1971). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa 30 (4): 37. ISSN 0024-8266. Bibcode1971MNSSA..30...37C. 
  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. Bibcode2006AstL...32..759G. 
  6. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation" (in en). Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode2012AstL...38..331A. 
  7. 7.0 7.1 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics 657: A7. doi:10.1051/0004-6361/202142146. ISSN 0004-6361. Bibcode2022A&A...657A...7K. 
  8. 8.0 8.1 8.2 8.3 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. ISSN 0004-6256. Bibcode2019AJ....158..138S. 
  9. 9.0 9.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  10. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society 471 (1): 770–791. doi:10.1093/mnras/stx1433. ISSN 0035-8711. Bibcode2017MNRAS.471..770M. 
  11. 11.0 11.1 De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars: V. Southern stars⋆⋆⋆". Astronomy & Astrophysics 561: A126. doi:10.1051/0004-6361/201220762. ISSN 0004-6361. Bibcode2014A&A...561A.126D. 
  12. "HR 6922". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+6922. 
  13. Gould, Benjamin Apthorp (1878). "Uranometria Argentina: brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral: con atlas". Resultados del Observatorio Nacional Argentino 1. Bibcode1879RNAO....1.....G. 
  14. 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. 
  15. Morton Wagman (2003). Lost Stars: Lost, Missing, and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas-Louis de Lacaille, John Flamsteed, and Sundry Others (2 ed.). McDonald & Woodward Publishing Company. ISBN 978-0-939923-78-6. OCLC 1131243914. https://books.google.com/books?id=TYLvAAAAMAAJ.