HD 215497 is a single[4] star in the southern constellation of Tucana. It has an orange hue with an apparent visual magnitude of 8.96,[2] which is too dim to be viewed with the naked eye. A 2015 survey ruled out the existence of any stellar companions at projected distances from 26 to 300 astronomical units.[6] Based on parallax measurements,[1] it is located at a distance of 132 light years from the Sun. The star is drifting further away with a radial velocity of +49 km/s, having come as close as 45 light-years some 774,000 years ago.[3] The absolute magnitude of this star is 5.77.[3]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Tucana |
| Right ascension | 22h 46m 36.75396s[1] |
| Declination | −56° 35′ 58.3285″[1] |
| Apparent magnitude (V) | 8.96[2] |
| Characteristics | |
| Spectral type | K3V[2] |
| Apparent magnitude (B) | 9.913[3] |
| Apparent magnitude (J) | 7.339±0.024[3] |
| Apparent magnitude (H) | 6.917±0.053[3] |
| Apparent magnitude (K) | 6.784±0.024[3] |
| B−V color index | 0.953±0.025[3] |
| Astrometry | |
| Radial velocity (Rv) | +49.31[3] km/s |
| Proper motion (μ) | RA: −54.660±0.041[1] mas/yr Dec.: −61.028±0.045[1] mas/yr |
| Parallax (π) | 24.6339 ± 0.0324 mas[1] |
| Distance | 132.4 ± 0.2 ly (40.59 ± 0.05 pc) |
| Absolute magnitude (MV) | 5.77[3] |
| Details[4] | |
| Mass | 0.86±0.02 M☉ |
| Radius | 0.87±0.02 R☉ |
| Luminosity | 0.47±0.02 L☉ |
| Surface gravity (log g) | 4.49±0.03 cgs |
| Temperature | 5,128±12 K |
| Metallicity [Fe/H] | 0.23±0.07[2] dex |
| Rotational velocity (v sin i) | 1.67[2] km/s |
| Age | 9.9±2.8 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
The stellar classification of HD 215497 is K3V,[2] indicating this is a K-type main-sequence star that is generating energy through core hydrogen fusion. The star is about ten[4] billion years old with a low magnetic activity level and is spinning with a projected rotational velocity of 1.67 km/s.[2] It is smaller than the Sun, with 86% of the Sun's mass and 87% of the radius.[4] This is a metal-rich star, which means the abundance of heavier elements in the atmosphere is significantly higher than in the Sun.[2] It is radiating 47% of the luminosity of the Sun from its photosphere at an effective temperature of 5,128 K.[4]
Planetary system
editAnnounced in 2009, two extrasolar planets were discovered to be orbiting the star.[2] Both planets are less massive than Jupiter. The inner exoplanet HD 215497 b orbits very close to the star and is termed a "hot super-Earth". The outer exoplanet HD 215497 c is a giant planet that orbits a little bit further from the star than the Earth, at around 1.282 AU, with a high eccentricity. A check for transits of the inner planet did not reveal any passages.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥6.6 M🜨 | 0.047 | 3.93404 ± 0.00066 | 0.16 ± 0.09 | — | — |
| c | ≥0.33 MJ | 1.282 | 567.94 ± 2.70 | 0.49 ± 0.04 | — | — |
References
edit- ^ a b c d e f 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 e f g h i j Lo Curto, G.; et al. (2015). "The HARPS search for southern extra-solar planets. XXII. Multiple planet systems from the HARPS volume limited sample". Astronomy and Astrophysics. 512. A48. arXiv:1411.7048. Bibcode:2010A&A...512A..48L. doi:10.1051/0004-6361/200913523.
- ^ a b c d e f g h i 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 c d e Bonfanti, A.; et al. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692. A5.
- ^ "HD 215497". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-08.
- ^ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340. Retrieved 19 June 2020.
- ^ Gillon, M.; et al. (May 2017). "The Spitzer search for the transits of HARPS low-mass planets. II. Null results for 19 planets". Astronomy & Astrophysics. 601: 23. arXiv:1701.01303. Bibcode:2017A&A...601A.117G. doi:10.1051/0004-6361/201629270. S2CID 86862862. A117.