HD 175740
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 18h 54m 52.17758s[1]
Declination +41° 36′ 09.7934″[1]
Apparent magnitude (V) 5.46[2]
Characteristics
Spectral type K0III[3]
B−V color index 1.034±0.004[2]
Astrometry
Radial velocity (Rv)−9.52±0.13[4] km/s
Proper motion (μ) RA: −2.059[1] mas/yr
Dec.: −2.234[1] mas/yr
Parallax (π)12.2448 ± 0.0874 mas[1]
Distance266 ± 2 ly
(81.7 ± 0.6 pc)
Absolute magnitude (MV)0.89[2]
Details
Mass1.39[5] or 2.795[4] M☉
Radius10.17+0.35
−0.73[1] R☉
Luminosity49.90±0.45[1] L☉
Surface gravity (log g)2.8[6] cgs
Temperature4,811+181
−81[1] K
Metallicity [Fe/H]−0.01±0.06[2] dex
Rotational velocity (v sin i)4.0[6] km/s
Age4.78[5] Gyr
Other designations
BD+41°3177, GC 25972, HD 175740, HIP 92831, HR 7146, SAO 47909, WDS J18549+4136A[7]
Database references
SIMBADdata

HD 175740 is a single[8] star in the northern constellation of Lyra.[2] This object has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.46.[2] It is located at a distance of approximately 266 light years from the Sun based on parallax,[1] and has an absolute magnitude of 0.89.[2] The star is drifting closer with a radial velocity of −9.5 km/s, and is predicted to come as close as 31.7 light-years in around 8 million years.[4]

This is an aging giant star with a stellar classification of K0III,[3] having evolving off the main sequence after the supply of hydrogen at its core was exhausted. It is an estimated 4.78[5] billion years old with 1.39[5] times the mass of the Sun, although Bailer-Jones et al. (2018) give a higher estimate of 2.8[4] times the Sun's mass. The elemental composition of this star has made it the first giant to be a candidate solar sibling, suggesting it may have been born in the same star cluster as the Sun.[9] It has expanded to ten[1] times the girth of the Sun and is radiating 50[1] times the Sun's luminosity from its photosphere at an effective temperature of 4,811 K.[1]

HD 175740 has a magnitude 12.6 visual companion, located at an angular separation of 8.4″ along a position angle (PA) of 300°, as of 2013. A magnitude 11.5 companion lies at a separation of 24.1″ along a PA of 39°, as of 2014. Both were discovered by American astronomer G. W. Hough in 1887.[10]

References

  1. ^ a b c d e f g h i j k l Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e f g Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  3. ^ a b Abt, H. A. (September 1985), "Visual multiples. VIII - 1000 MK types", Astrophysical Journal Supplement Series, 59: 95–112, Bibcode:1985ApJS...59...95A, doi:10.1086/191064
  4. ^ a b c d Bailer-Jones, C.A.L.; et al. (2018), "New stellar encounters discovered in the second Gaia data release", Astronomy & Astrophysics, 616: A37, arXiv:1805.07581, Bibcode:2018A&A...616A..37B, doi:10.1051/0004-6361/201833456, S2CID 56269929.
  5. ^ a b c d Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  6. ^ a b Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  7. ^ "HD 175740". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-02-09.
  8. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  9. ^ Ramírez, I.; et al. (June 2014), "Elemental Abundances of Solar Sibling Candidates", The Astrophysical Journal, 787 (2): 17, arXiv:1405.1723, Bibcode:2014ApJ...787..154R, doi:10.1088/0004-637X/787/2/154, S2CID 118441281, 154.
  10. ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
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