Astronomy:HD 163840
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hercules |
| Right ascension | 17h 57m 14.33667s[1] |
| Declination | +23° 59′ 44.5562″[1] |
| Apparent magnitude (V) | 6.4543±0.0005[1] (6.30 + 7.90)[2] |
| Characteristics | |
| Spectral type | G2 V + K2 V[3] |
| B−V color index | 0.642±0.006[1] |
| Astrometry | |
| Radial velocity (Rv) | −32.83±0.07[4] km/s |
| Proper motion (μ) | RA: −17.79±0.33[1] mas/yr Dec.: +73.56±0.47[1] mas/yr |
| Parallax (π) | 35.40 ± 0.62[1] mas |
| Distance | 92 ± 2 ly (28.2 ± 0.5 pc) |
| Absolute magnitude (MV) | 4.05[5] |
| Orbit[6] | |
| Period (P) | 881.628±0.064 d |
| Semi-major axis (a) | 80.64 mas |
| Eccentricity (e) | 0.4165±0.0010 |
| Inclination (i) | 72.83±0.47° |
| Longitude of the node (Ω) | 175.32±0.44° |
| Periastron epoch (T) | 55650.39 ± 0.38 (BJD−2400000) |
| Argument of periastron (ω) (secondary) | 135.46±0.16° |
| Details | |
| HD 163840 A | |
| Mass | 1.132±0.014[6] M☉ |
| Luminosity | 2.031[3] L☉ |
| Temperature | 5,860[3] K |
| Metallicity [Fe/H] | 0.06[5] dex |
| Age | 7.4[5] Gyr |
| HD 163840 B | |
| Mass | 0.7421±0.0073[6] M☉ |
| Luminosity | 0.648[3] L☉ |
| Temperature | 4,780[3] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 163840 is a binary star[6] system in the northern constellation of Hercules. It has a combined apparent visual magnitude of 6.45,[1] which falls just below the brightness level that is visible to the naked eye for people with normal eyesight. An annual parallax shift of 35.40[1] mas provides a distance estimate of about 92 light years. The system is moving closer to the Sun with a radial velocity of −33 km/s.[4] In about 769,000 years, it will make perihelion at a separation of around 27.2 ly (8.33 pc).[8]
R. K. Young of the Dominion Astrophysical Observatory was the first to recognize the variable radial velocity of this system.[9] In 1974, Harold A. McAlister and Philip A. Ianna identified it as a nearby G-type dwarf based on its spectroscopic properties.[10] McAlister et al. (1974) found it to be a spectroscopic binary[10] and the components were first resolved in 1976. A series of observations since that time allowed the system's orbital elements to be published by McAlister et al. (1995), along with estimates of the stellar masses of the two components.[11] These parameters have been further refined using improved instruments up through 2016.[6]
The pair of stars orbit each other with a period of 881.6 days (2.414 a) and an eccentricity of 0.417. The plane of their orbit is inclined by an angle of 73° to the line of sight from the Earth, with a semimajor axis having an angular value of 80.64 mas.[6] The close, eccentric orbit of the pair does not permit a stable planetary orbit in the habitable zone of either component.[3]
The primary, component A, is a magnitude 6.30[2] G-type main-sequence star with a stellar classification of G2 V.[3] It has 1.13[6] times the mass of the Sun and is radiating double the Sun's luminosity from its photosphere at an effective temperature of 5,860 K.[3] Component B, the magnitude 7.90[2] secondary, is a smaller K-type main-sequence star with a class of K2 V.[3] It has 0.74[6] times the Sun's mass and shines with 0.65[3] times the Sun's luminosity at an effective temperature of 4,780 K.[3] The system as a whole may be around 7.4[5] billion years old with a slightly higher metallicity than the Sun. The system displays solar-like variability.[12]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 Eggl, S. et al. (2012), "Circumstellar habitable zones of binary-star systems in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society 428 (4): 3104, doi:10.1093/mnras/sts257, Bibcode: 2013MNRAS.428.3104E.
- ↑ 4.0 4.1 Pourbaix, D. et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics 424: 727–732, doi:10.1051/0004-6361:20041213, Bibcode: 2004A&A...424..727P.
- ↑ 5.0 5.1 5.2 5.3 Holmberg, J. et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Kiefer, F. et al. (May 2016), "Masses of the components of SB2 binaries observed with Gaia - III. Accurate SB2 orbits for 10 binaries and masses of HIP 87895", Monthly Notices of the Royal Astronomical Society 458 (3): 3272−3281, doi:10.1093/mnras/stw545, Bibcode: 2016MNRAS.458.3272K.
- ↑ "HD 163840". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+163840.
- ↑ Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics 575: 13, doi:10.1051/0004-6361/201425221, A35, Bibcode: 2015A&A...575A..35B.
- ↑ Culver, R. et al. (September 1980), "HR 6697: A Nearby G-Star Binary System", Bulletin of the American Astronomical Society 12: 850, Bibcode: 1980BAAS...12..850C.
- ↑ 10.0 10.1 McAlister, Harold A.; Ianna, Philip A. (October 1974), "Possible Nearby F and G Dwarfs", Publications of the Astronomical Society of the Pacific 86 (513): 769, doi:10.1086/129672, Bibcode: 1974PASP...86..769M.
- ↑ McAlister, H. A. et al. (July 1995), "Binary Star Orbits from Speckle Interferometry. VI. The Nearby Solar-Type Speckle-Spectroscopic Binary HR 6697", Astronomical Journal 110: 366, doi:10.1086/117527, Bibcode: 1995AJ....110..366M.
- ↑ Hall, Jeffrey C. et al. (March 2007), "The Activity and Variability of the Sun and Sun-like Stars. I. Synoptic Ca II H and K Observations", The Astronomical Journal 133 (3): 862–881, doi:10.1086/510356, Bibcode: 2007AJ....133..862H.
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