HD 215497

From Wikipedia, the free encyclopedia
HD 215497
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[1] mas
Distance132.4 ± 0.2 ly
(40.59 ± 0.05 pc)
Absolute magnitude (MV)5.77[3]
Details[4]
Mass0.86±0.02 M
Radius0.87±0.02 R
Luminosity0.47±0.02 L
Surface gravity (log g)4.49±0.03 cgs
Temperature5,128±12 K
Metallicity [Fe/H]0.23±0.07[2] dex
Rotational velocity (v sin i)1.67[2] km/s
Age9.9±2.8 Gyr
Other designations
CPD−57°10139, HD 215497, HIP 112441, SAO 247578, PPM 350516, TYC 8826-00247-1, 2MASS J22463675-5635584[5]
Database references
SIMBADdata
Exoplanet Archivedata

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]

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[]

Announced 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]

The HD 215497 planetary system[2]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ≥6.6 M
WIKI