HD 113538 (Gliese 496.1) is a star with two planetary companions in the southern constellation of Centaurus. 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]

Planetary system

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.