HD 162020
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 50m 38.35457s[1] |
| Declination | −40° 19′ 06.0801″[1] |
| Apparent magnitude (V) | 9.10[2] |
| Characteristics | |
| Spectral type | K3V[3] |
| B−V color index | 0.964±0.066[2] |
| Astrometry | |
| Radial velocity (Rv) | −26.55±2.30[1] km/s |
| Proper motion (μ) | RA: +20.276[1] mas/yr Dec.: −25.320[1] mas/yr |
| Parallax (π) | 32.4128 ± 0.0745 mas[1] |
| Distance | 100.6 ± 0.2 ly (30.85 ± 0.07 pc) |
| Absolute magnitude (MV) | 6.76[2] |
| Details | |
| Mass | 0.741±0.019 M☉[4] 0.75±0.01[5] M☉ |
| Radius | 0.73+0.02 −0.01 R☉[1] 0.68±0.01[5] R☉ |
| Luminosity | 0.258±0.001 L☉[1] 0.22±0.01[5] L☉ |
| Surface gravity (log g) | 4.76±0.25[6] 4.63±0.01[5] cgs |
| Temperature | 4,801+39 −52[1] K |
| Metallicity [Fe/H] | 0.01±0.11[6] dex |
| Rotational velocity (v sin i) | 1.9[6] km/s |
| Age | 5.7±4.7 Gyr[4] 3.1±2.7[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 162020 is a star in the southern constellation of Scorpius with a brown dwarf companion. It has an apparent visual magnitude of 9.10,[2] which is too faint to be visible to the naked eye. The distance to this system is 101 light years based on stellar parallax.[1] It is drifting closer to the Sun with a radial velocity of −27 km/s,[1] and is predicted to come to within ~18 light-years in 1.1 million years.[8]
This is an ordinary K-type main-sequence star with a stellar classification of K3V.[3] The age estimate is poorly constrained but it appears to have an intermediate age of several billion years. However, the activity level suggests a younger star; the rotation rate of the star may have been increased through synchronization with the companion, resulting in a higher than normal activity for its age.[6] X-ray emission has been detected from this star.[9]
HD 162020 has 74%[4] of the mass of the Sun and 73%[1] of the Sun's radius. The abundance of iron is roughly the same as the Sun, suggesting a similar metallicity. It is radiating just 25.8% of the luminosity of the Sun from its photosphere at an effective temperature of 4,801 K.[1] The star is spinning with a projected rotational velocity of 1.9 km/s.[6]
Companion
| Discovery | |
|---|---|
| Discovered by | Udry et al. |
| Discovery date | April 15, 2000[10] |
| Doppler Spectroscopy | |
| Orbital characteristics | |
| 00,751 AU (1.123×1011 km) | |
| Eccentricity | 0.277 ± 0.02 |
| 8.428198 ± 0.000056 d | |
| 2451990.6768 ± 0.0050 | |
| 28.40 ± 0.23 | |
| Semi-amplitude | 1,813 ± 4 |
| Physical characteristics | |
| Mass | >15.0 MJ |
HD 162020 b is a brown dwarf companion with a minimum mass of at least 15.0 MJ. The actual mass is undetermined since the orbital inclination is not known. This planetar orbits very close to the star at a distance of 0.075 AU with an eccentricity (ovalness) of 0.277. The object's distance from the star ranges from 0.054 to 0.096 AU. It has an extremely high semi-amplitude of 1,813 km/s. The discovery was announced on April 15, 2000 by the Geneva Extrasolar Planet Search Team.[10][6]
Despite the presence of this massive object in an eccentric orbit around the star, computer modelling shows it is still theoretically possible for an Earth-mass exoplanet to be occupying a dynamically-stable orbit in the habitable zone of this star.[11]
References
- ^ a b c d e f g h i j k l m 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.
- ^ a b c d 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.
- ^ a b Torres, C. A. O.; et al. (December 2006). "Search for associations containing young stars (SACY). I. Sample and searching method". Astronomy and Astrophysics. 460 (3): 695–708. arXiv:astro-ph/0609258. Bibcode:2006A&A...460..695T. doi:10.1051/0004-6361:20065602. S2CID 16080025.
- ^ a b c Delgado Mena, E.; et al. (April 2019). "Abundance to age ratios in the HARPS-GTO sample with Gaia DR2. Chemical clocks for a range of [Fe/H]". Astronomy & Astrophysics. 624: 24. arXiv:1902.02127. Bibcode:2019A&A...624A..78D. doi:10.1051/0004-6361/201834783. A78.
- ^ a b c d e Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: A5, 14 pp. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692.
- ^ a b c d e f Udry, M.; et al. (2002). "The CORALIE survey for southern extra-solar planets VIII. The very low-mass companions of HD 141937, HD 162020, HD 168443, HD 202206: Brown dwarfs or "superplanets"?". Astronomy and Astrophysics. 390 (1): 267–279. arXiv:astro-ph/0202458. Bibcode:2002A&A...390..267U. doi:10.1051/0004-6361:20020685.
- ^ "HD 162020". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-04-02.
- ^ Bailer-Jones, C.A.L.; et al. (2018). "New stellar encounters discovered in the second Gaia data release". Astronomy & Astrophysics. 616: A37. arXiv:1805.07581. Bibcode:2018A&A...616A..37B. doi:10.1051/0004-6361/201833456.
- ^ Poppenhaeger, K.; Schmitt, J. H. M. M. (July 2011). "A Correlation Between Host Star Activity and Planet Mass for Close-in Extrasolar Planets?". The Astrophysical Journal. 735 (1): 5. arXiv:1106.0189. Bibcode:2011ApJ...735...59P. doi:10.1088/0004-637X/735/1/59. 59.
- ^ a b "Exoplanets Galore!" (Press release). Garching, Germany: European Southern Observatory. April 15, 2000. Retrieved December 30, 2012.
- ^ Agnew, Matthew T.; Maddison, Sarah T.; Thilliez, Elodie; Horner, Jonathan (2017). "Stable habitable zones of single Jovian planet systems". Monthly Notices of the Royal Astronomical Society. 471 (4): 4494–4507. arXiv:1706.05805. Bibcode:2017MNRAS.471.4494A. doi:10.1093/mnras/stx1449. S2CID 119227856.
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External links
- "Notes for star HD 162020". The Extrasolar Planets Encyclopaedia. Retrieved December 21, 2007.
- "Notes for planet HD 162020 b". The Extrasolar Planets Encyclopaedia. Retrieved December 21, 2007.
