HR 7135

HR 7135 is a binary star system. Despite its Flamsteed designation of 62 Serpentis, the star can be found in the equatorial constellation of Aquila,^[10] in front of a dark rift in the Milky Way near the constellation border.^[5] It is visible to the naked eye as a dim, yellow-hued point of light with an apparent visual magnitude of 5.57.^[2] The system is located 283 light years distant from the Sun, based on parallax,^[1] and is drifting further away with a radial velocity of 23 km/s.^[5]

HR 7135

Observation data Epoch J2000      Equinox J2000
Constellation	Aquila
Right ascension	18h 55m 27.46151s[1]
Declination	+06° 36′ 55.1499″[1]
Apparent magnitude (V)	5.57[2]
Characteristics
Spectral type	G9 III[3]
U−B color index	+0.87[2]
B−V color index	+1.041±0.002[4]
Astrometry
Radial velocity (Rv)	23.31±0.09[5] km/s
Proper motion (μ)	RA: +7.972[1] mas/yr Dec.: –92.211[1] mas/yr
Parallax (π)	11.5405 ± 0.1636 mas[1]
Distance	283 ± 4 ly (87 ± 1 pc)
Absolute magnitude (MV)	0.87[4]
Orbit[5][6]
Primary	HR 7135 A
Companion	HR 7135 B
Period (P)	2,994±29 d
Semi-major axis (a)	26.6±3.4 mas
Eccentricity (e)	0.243±0.026
Inclination (i)	31.9±3.6°
Longitude of the node (Ω)	12.6±7.7°
Periastron epoch (T)	2444276.5±52 JD
Argument of periastron (ω) (secondary)	35±7°
Semi-amplitude (K1) (primary)	4.65±0.13 km/s
Details
HR 7135 A
Mass	1.54[7] M☉
Radius	10.69+0.17 −0.93[1] R☉
Luminosity	52.8±0.9[1] L☉
Surface gravity (log g)	2.7[8] cgs
Temperature	4,666±51[7] K
Metallicity [Fe/H]	–0.26[8] dex
Rotational velocity (v sin i)	0.0[8] km/s
Age	3.21[7] Gyr
Other designations
62 Ser, BD+06°3978, FK5 3509, HD 175515, HIP 92872, HR 7135, SAO 124050[9]
Database references
SIMBAD	data

Discovery of the binary nature of this system is credited to Canadian astronomer H. H. Plaskett in 1922. It is a single-lined spectroscopic binary with an orbital period of 8.2 years and an eccentricity of 0.24.^[5][6] The visible component is an aging giant star with a stellar classification of G9 III,^[3] having exhausted the supply of hydrogen at its core and expanded to 10.7^[1] times the Sun's radius. It is a red clump giant, indicating it is on the horizontal branch and is generating energy via core helium fusion.^[11] The star is 3.2^[7] billion years old with 1.54^[7] times the mass of the Sun. It is radiating 53^[1] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,666 K.^[7] The star has a very low rate of spin, with the projected rotational velocity being too small to measure.^[8]

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. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
3. McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527
4. 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.
5. Griffin, R. F. (1981), "Spectroscopic binary orbits from photoelectric radial velocities. Paper 41: HR 7135", The Observatory, 101: 208–211, Bibcode:1981Obs...101..208G.
6. Jancart, S.; et al. (2005), "Astrometric orbits of SB9 stars", Astronomy and Astrophysics, 442 (1): 365–380, arXiv:astro-ph/0507695, Bibcode:2005A&A...442..365J, doi:10.1051/0004-6361:20053003, S2CID 15123997.
7. 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.
8. 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.
9. "HD 175515". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-04.
10. Kaler, James B. (1996), The ever-changing sky: a guide to the celestial sphere, Cambridge University Press, p. 119, ISBN 0-521-38053-7.
11. Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.