HD 136118

HD 136118 is a star in the Serpens Caput section of the Serpens Cauda constellation. The star is too dim to be readily visible to the naked eye, having an apparent visual magnitude of 6.93.[2] It is located at a distance of 168 light years from the Sun based on parallax,[1] and is drifting closer with a radial velocity of −3 km/s.[2]

HD 136118
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension  15h 18m 55.4719s[1]
Declination −01° 35′ 32.590″[1]
Apparent magnitude (V) 6.93[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type F7V[4]
B−V color index 0.553±0.007[2]
Astrometry
Radial velocity (Rv)−2.97±0.12[2] km/s
Proper motion (μ) RA: −123.748±0.112[1] mas/yr
Dec.: +22.522±0.151[1] mas/yr
Parallax (π)19.4132 ± 0.0741[1] mas
Distance168.0 ± 0.6 ly
(51.5 ± 0.2 pc)
Absolute magnitude (MV)3.60[5]
Details
Mass1.84±0.23[6] M☉
Radius1.70±0.02[1] R☉
Luminosity3.717±0.018[1] L☉
Surface gravity (log g)4.08[5] cgs
Temperature6,148+38
−43[1] K
Metallicity [Fe/H]−0.06±0.01[2] dex
Rotational velocity (v sin i)8.5[5] km/s
Age3.5±0.4[2] Gyr
Other designations
BD−01° 3045, HD 136118, HIP 74948, SAO 140452[7]
Database references
SIMBADdata

This object is an F-type main-sequence star with a stellar classification of F7V.[4] The absolute visual magnitude of this star suggests that it has begun to evolve away from the main sequence.[3] The abundances of the stellar atmosphere are similar to the Sun, and it has only a modest level of chromospheric activity.[8] HD 136118 has 84% more mass compared to the Sun,[6] and is 70%[1] larger in radius. The star is an estimated 3.5[2] billion years old and is spinning with a projected rotational velocity of 8.5 km/s.[5]

Brown dwarf companion

The astronomer Debra Fischer discovered a very massive planet, which was announced on February 7, 2002.[3] On November 25, 2009, the object turned out to be a brown dwarf.[8] Designated HD 136118 b, it is orbiting the host star with a period of 3.25 years.[8]

The HD 136118 planetary system[8]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 15.49±1.33[6] MJ 1.45±0.25[3] 1,188±2 0.34±0.01 163.1±3.0° —

See also

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. Fischer, Debra A.; et al. (2002). "Planetary Companions to HD 136118, HD 50554, and HD 106252". Publications of the Astronomical Society of the Pacific. 114 (795): 529–535. Bibcode:2002PASP..114..529F. doi:10.1086/341677. JSTOR 10.1086/341677.
  4. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  5. Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 19. arXiv:1611.02897. Bibcode:2017AJ....153...21L. doi:10.3847/1538-3881/153/1/21. 21.
  6. Stassun, Keivan G.; et al. (2017). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal. 153 (3): 136. arXiv:1609.04389. Bibcode:2017AJ....153..136S. doi:10.3847/1538-3881/aa5df3.
  7. "HD 81040". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-13.
  8. Martioli, Eder; et al. (January 2010). "The Mass of the Candidate Exoplanet Companion to HD 136118 from Hubble Space Telescope Astrometry and High-Precision Radial Velocities". The Astrophysical Journal. 708 (1): 625–634. arXiv:0911.4645. Bibcode:2010ApJ...708..625M. doi:10.1088/0004-637X/708/1/625.

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