HD 136118
HD 136118 is a star in the Serpens Caput section of the Serpens 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]
| 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 |
| Distance | 168.0 ± 0.6 ly (51.5 ± 0.2 pc) |
| Absolute magnitude (MV) | 3.60[5] |
| Details | |
| Mass | 1.84±0.23[6] M☉ |
| Radius | 1.70±0.02[1] R☉ |
| Luminosity | 3.717±0.018[1] L☉ |
| Surface gravity (log g) | 4.08[5] cgs |
| Temperature | 6,148+38 −43[1] K |
| Metallicity [Fe/H] | −0.06±0.01[2] dex |
| Rotational velocity (v sin i) | 8.5[5] km/s |
| Age | 3.5±0.4[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
| Discovery | |
|---|---|
| Discovered by | Fischer "et al."[3] |
| Discovery site |  California |
| Discovery date | February 7, 2002 |
| Doppler Spectroscopy | |
| Orbital characteristics | |
| Apastron | 1.96 AU (293,000,000 km) |
| Periastron | 0.94 AU (141,000,000 km) |
| 1.45 ± 0.25 AU (217,000,000 ± 37,000,000 km) | |
| Eccentricity | 0.352 ± 0.006 |
| 1209 ± 24 d 3.31 y | |
| Inclination | 163.1 ± 3 |
| 2450610.5 ± 3.7 | |
| 316.4 ± 0.6 | |
| Star | HD 136118 |
| Physical characteristics | |
| Mass | 42+11 −18 MJ |
The astronomer Debra Fischer discovered a substellar companion, originally thought to be a very massive exoplanet, which was announced on February 7, 2002. This object has a minimum mass of 11.9 MJ.[3] On November 25, 2009, its inclination was calculated to be 163.1° and its true mass 42 MJ, classifying it as a brown dwarf.[8] Designated HD 136118 b, it is orbiting the host star with a period of 3.25 years.[8]
Due to its high mass the object is likely to be very hot and possibly glowing faintly. The orbit of the object has a semimajor axis of 1.45 astronomical units from the parent star, taking 1,188 days (3.25 years) to complete one eccentric orbit.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 42+11 −18 MJ |
1.45±0.25[3] | 1,188±2 | 0.34±0.01 | 163.1±3.0° | — |
See also
References
- 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.
- 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.
- 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.
- Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- 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.
- 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.
- "HD 81040". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-13.
- 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.
External links
- "Notes for star HD 136118". The Extrasolar Planets Encyclopaedia. Retrieved 2008-08-20.