| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13h04m 57.47645s[1] |
| Declination | −52° 26′ 34.5284″[1] |
| Apparent magnitude (V) | 9.05[2] |
| Characteristics | |
| Spectral type | K9Vk:[3] |
| B−V color index | 1.362±0.009[2] |
| Astrometry | |
| Radial velocity (Rv) | 39.23±0.012[4] km/s |
| Proper motion (μ) | RA: −786.038[1] mas/yr Dec.: −795.591[1] mas/yr |
| Parallax (π) | 61.3899 ± 0.0523 mas[1] |
| Distance | 53.13 ± 0.05 ly (16.29 ± 0.01 pc) |
| Absolute magnitude (MV) | 8.03[4] |
| Details[4] | |
| Mass | 0.585±0.05 M☉ |
| Radius | 0.53±0.02 R☉ |
| Luminosity | 0.127[1] L☉ |
| Surface gravity (log g) | 3.79±0.53 cgs |
| Temperature | 4,462±145 K |
| Metallicity [Fe/H] | −0.24±0.06 dex |
| Age | 4.3±4.0 Gyr |
| Other designations | |
CD−51 7244, GJ 496.1/9425, HD 113538, HIP 63833, LFT 966, LHS 344[5] | |
| Database references | |
| SIMBAD | data |
HD 113538 (Gliese 496.1) is a star with two planetary companions in the southern constellationofCentaurus. It is much too faint to be viewed with the naked eye at an apparent visual magnitude of 9.05.[2] The distance to this star is 53 light years and it is drifting further away with a radial velocity of +39 km/s.[4]
This is a K-type main-sequence star of a late spectral type, classified as K9Vk:. It displays chromospheric activity with a stellar cycle of at least four years and is metal poor.[4] The star has 58.5% of the mass and 53% of the radius of the Sun.[4] It is radiating just 12.7%[1] of the luminosity of the Sun from its photosphere at an effective temperature of 4,462 K.[4]
Radial velocity variation of HD 113538 was inferred from observations with the HARPS spectrograph. The star is active (Log R'HK −4.697,[6] SMW 1.05[4]), but the RV variation is not correlated with activity, indicating that planets are responsible. The data is fitted well by a solution including two planets, with an eccentric Saturn-mass planet and a more massive planet on a longer-period orbit[7]—similar to the orbital architecture of the planetary system orbiting HD 163607, though with lower masses. Similar to HD 163607 b, the eccentricity and argument of periastron of HD 113538 b increases the planet's transit probability substantially more than it would be on a circular orbit.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 0.36±0.04 MJ | 1.24±0.04 | 663.2+8.4 −7.4 |
0.14±0.08 | — | — |
| c | ≥ 0.93±0.06 MJ | 2.44±0.07 | 1,818+25 −22 |
0.20±0.04 | — | — |
