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]

HD 113538
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 13h 04m 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]
Distance53.13 ± 0.05 ly
(16.29 ± 0.01 pc)
Absolute magnitude (MV)8.03[4]
Details[4]
Mass0.585±0.05 M
Radius0.53±0.02 R
Luminosity0.127[1] L
Surface gravity (log g)3.79±0.53 cgs
Temperature4,462±145 K
Metallicity [Fe/H]−0.24±0.06 dex
Age4.3±4.0 Gyr
Other designations
CD−51 7244, GJ 496.1/9425, HD 113538, HIP 63833, LFT 966, LHS 344[5]
Database references
SIMBADdata

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

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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.

The HD 113538 planetary system[4]
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

References

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  1. ^ a b c d e f g Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. ^ Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  4. ^ a b c d e f g h i Moutou, Claire; et al. (April 2015). "The HARPS search for southern extra-solar planets. XXXVII. Five new long-period giant planets and a system update". Astronomy & Astrophysics. 576: 14. arXiv:1412.6591. Bibcode:2015A&A...576A..48M. doi:10.1051/0004-6361/201424965. A48.
  5. ^ "HD 113538". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-03.
  6. ^ Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  7. ^ Moutou, Claire; Mayor, Michel; Lo Curto, Gaspare; Ségransan, Damien; Udry, Stéphane; Bouchy, François; Benz, Willy; Lovis, Christophe; Naef, Dominique; Pepe, Francesco; Queloz, Didier; Santos, Nuno C.; Sousa, Sérgio Gonçalves (2010), The HARPS search for southern extra-solar planets: XXVI: Seven new planetary systems, arXiv:1012.3830, doi:10.1051/0004-6361/201015371, S2CID 118696125