Qatar-2
Star in the constellation Virgo
From Wikipedia, the free encyclopedia
Qatar-2 is a K-type main-sequence star about 595 light-years away in the constellation of Virgo. The star is much older than Sun, and has a concentration of heavy elements similar to solar abundance.[3] The star features a numerous and long-lived starspots,[6] and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection.[9]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Virgo[1] |
| Right ascension | 13h 50m 37.4100s[2] |
| Declination | −06° 48′ 14.422″[2] |
| Apparent magnitude (V) | 13.3[3] |
| Characteristics | |
| Spectral type | K5V[4] |
| Astrometry | |
| Radial velocity (Rv) | −23.55[5] km/s |
| Proper motion (μ) | RA: −88.171[2] mas/yr Dec.: −15.187[2] mas/yr |
| Parallax (π) | 5.4023±0.0195 mas[2] |
| Distance | 604 ± 2 ly (185.1 ± 0.7 pc) |
| Details[6][3] | |
| Mass | 0.727±0.024 M☉ |
| Radius | 0.7033±0.0080 R☉ |
| Surface gravity (log g) | 4.601±0.018 cgs |
| Temperature | 4,645±50 K |
| Metallicity [Fe/H] | 0.13±0.1[7] dex |
| Rotation | 18.0±0.2 |
| Rotational velocity (v sin i) | 2.0±0.2 km/s |
| Age | 9 Gyr |
| Other designations | |
| GSC 04974-00112, 2MASS J13503740-0648145, Gaia DR2 3620030644476623616[8] | |
| Database references | |
| SIMBAD | data |
Planetary system
In 2011 a transiting superjovian planet Qatar-2b was detected by the Qatar Exoplanet Survey.[3] The planet has a large measured temperature difference between dayside 1,368±32 K and nightside 724±135 K.[10] The planetary orbit is well aligned with the equatorial plane of the star,[7] misalignment angle equal to 4.3°±4.5°.[11] No orbital decay was detected.[12] The color of planetary atmosphere is blue due to Rayleigh scattering of light,[11] and albedo is very low, being below 0.06.[12]
An additional massive companion on wide orbit was suspected in 2011,[3] but search utilizing transit-timing variation method has yielded zero results in 2017.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 2.466±0.062 MJ | 0.02136±0.00024 | 1.33711677±0.00000010 | 0 | 88.99±0.20° | 1.115±0.013 RJ |
