111 Herculis

111 Herculis
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension  18h 47m 01.23246s[1]
Declination +21° 46′ 53.4381″[1]
4.34[2]
Characteristics
Spectral type A5III[3]
B−V color index 0.148±0.003[2]
Astrometry
Radial velocity (Rv)−44.6±2.7[2] km/s
Proper motion (μ) RA: +100.536[1] mas/yr
Dec.: +116.333[1] mas/yr
Parallax (π)35.3525 ± 0.2680[1] mas
Distance92.3 ± 0.7 ly
(28.3 ± 0.2 pc)
Absolute magnitude (MV)2.04[2]
Details
Mass2.40[4] M
Luminosity12.84[2] L
Surface gravity (log g)4.35[4] cgs
Temperature8,873±302[4] K
Metallicity [Fe/H]0.33[6] dex
Rotational velocity (v sin i)71[4] km/s
Age559[4] Myr
Other designations
111 Her, BD+18°3823, FK5 1491, HD 173880, HIP 92161, HR 7069, SAO 104093, WDS J18470+1811[7]
Database references

111 Herculis is a suspected astrometric binary[8] star system located 92 light years from the Sun in the northern constellation Hercules. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.34.[2] The system is moving nearer to the Earth with a heliocentric radial velocity of −45 km/s, and may come as close as 37 light-years in 537,000 years.[2]

According to Cowley et al. (1969), the visible component has a stellar classification of A5III,[3] matching an A-type giant star. Abt and Morrell (1995) listed it as type A3IV, suggesting it is instead a less evolved subgiant star.[9] The interferometry-measured angular diameter of the primary component is 0.52±0.02 mas,[10] which, at its estimated distance, equates to a physical radius of roughly 1.6 times the radius of the Sun.[5] The star is estimated to be 559[4] million years old with 2.40[4] times the mass of the Sun and is spinning with a projected rotational velocity of 71 km/s.[4] It is radiating 13 times the Sun's luminosity from its photosphere at an effective temperature of 8,873 K.[4]

References

1. 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. 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.
3. ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
4. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
5. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
{\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 28.3\cdot 0.52)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 3.2\cdot R_{\bigodot }\end{aligned}}}
6. ^ Erspamer, D.; North, P. (February 2003), "Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE", Astronomy and Astrophysics, 398: 1121–1135, arXiv:astro-ph/0210065, Bibcode:2003A&A...398.1121E, doi:10.1051/0004-6361:20021711.
7. ^ "111 Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-18.
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.
9. ^ Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
10. ^ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039