HAT-P-23
Star in the constellation Delphinus
From Wikipedia, the free encyclopedia
HAT-P-23 is a G-type main-sequence star 1192 light-years away. It has a rapid rotation (rotation period equal to 7 days) for its advanced age of 4 billion years, and exhibits a strong starspot activity.[7] The star may be in the process of being spun up by the giant planet on close orbit.[8] The star is enriched in heavy elements, having about 140% amount of metals compared to solar abundance.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Delphinus[1] |
| Right ascension | 20h 24m 29.7235s[2] |
| Declination | +16° 45′ 43.812″[2] |
| Apparent magnitude (V) | 11.94[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | G0[4] |
| Apparent magnitude (J) | 11.103±0.022[5] |
| Apparent magnitude (H) | 10.846±0.022[5] |
| Apparent magnitude (K) | 10.791±0.020[5] |
| Variable type | Planetary transit[4] |
| Astrometry | |
| Radial velocity (Rv) | −16.67±0.88[2] km/s |
| Proper motion (μ) | RA: 13.325(11) mas/yr[2] Dec.: −5.505(11) mas/yr[2] |
| Parallax (π) | 2.7358±0.0108 mas[2] |
| Distance | 1,192 ± 5 ly (366 ± 1 pc) |
| Details[4] | |
| Mass | 1.13±0.035 M☉ |
| Radius | 1.203±0.074 R☉ |
| Luminosity | 1.58±0.23 L☉ |
| Surface gravity (log g) | 4.33±0.05 cgs |
| Temperature | 5905±80 K |
| Metallicity | 0.15±0.04 |
| Rotation | 7.015 d[6] |
| Rotational velocity (v sin i) | 8.1±0.5 km/s |
| Age | 4.0±1.0 Gyr |
| Other designations | |
| Moriah, TYC 1632-1396-1, GSC 01632-01396, 2MASS J20242972+1645437[3] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Naming
In 2019, the HAT-P-23 star has received a proper name Moriah and planet HAT-P-23b - Jebus at an international NameExoWorlds contest.[9] These names mean the ancient name of the mount at the center of Jerusalem city, and ancient (pre-Roman) name of Jerusalem itself, respectively.
Planetary system
In 2010, a transiting hot Jupiter-like planet was detected.[4] It has a measured dayside temperature of 2154±90 K.[10] The planet is believed to be on an unstable orbit, and expected to be engulfed by its parent star about 7.5+2.9
−1.8 million years from now,[4] although timing measurements of multiple transits since the discovery have been unable to detect any reduction in the orbital period.[6][11] The planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to 15±22°.[12] The color of planetary atmosphere is grey.[13] The atmosphere is mostly devoid of clouds, and shows tentatively a presence of titanium(II) oxide.[14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b (Jebus) | 2.09±0.111 MJ | 0.0232±0.0002 | 1.2128868±0.0000004 | 0.096 | 85.1±1.5 | 1.224±0.037 RJ |