HD 213240

HD 213240 is a possible binary star[8] system in the constellation Grus. It has an apparent visual magnitude of 6.81,[2] which lies below the limit of visibility for normal human sight. The system is located at a distance of 133.5 light years from the Sun based on parallax. The primary has an absolute magnitude of 3.77.[2]

HD 213240

Observation data Epoch J2000      Equinox J2000
Constellation	Grus
Right ascension	22^h 31^m 00.36652^s[1]
Declination	−49° 25′ 59.7675″[1]
Apparent magnitude (V)	6.81[2]
Characteristics
Spectral type	G0/G1V[3]
B−V color index	0.603±0.005[2]
Astrometry
Radial velocity (Rv)	−0.52±0.18[1] km/s
Proper motion (μ)	RA: −136.026±0.047[1] mas/yr Dec.: −193.926±0.052[1] mas/yr
Parallax (π)	24.4385 ± 0.0372[1] mas
Distance	133.5 ± 0.2 ly (40.92 ± 0.06 pc)
Absolute magnitude (MV)	3.77[2]
Details
Mass	1.57±0.02[4] M☉
Radius	1.56+0.03 −0.04[1] R☉
Luminosity	2.687+0.007 −0.006[1] L☉
Surface gravity (log g)	4.17±0.02[5] cgs
Temperature	5,921+70 −58[1] K
Metallicity [Fe/H]	0.14±0.01[2] dex
Rotational velocity (v sin i)	3.5[6] km/s
Age	4.6±0.6[5] Gyr
Other designations
CPD−50° 13701, HD 213240, HIP 111143, SAO 231175, LTT 9047[7]
Database references
SIMBAD	data
Extrasolar Planets Encyclopaedia	data

This is an ordinary G-type main-sequence star with a stellar classification of G0/G1V.[3] It is a metal-rich star with an age has been calculated as being anywhere from 2.7 to 4.6 billion years.[8] The star has 1.6[4] times the mass of the Sun and 1.56[1] times the Sun's radius. It is spinning with a projected rotational velocity of 3.5 km/s.[6] The star is radiating 2.69[1] times the luminosity of the Sun from its photosphere at an effective temperature of 5,921 K.[1]

A red dwarf companion star was detected in 2005 with a projected separation of 3,898 AU.[8]

Planetary system

The Geneva extrasolar planet search team discovered a planet orbiting this star in 2001.[9] There is a 5% chance this is actually a brown dwarf.[8]

The HD 213240 planetary system[10]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥4.72±0.40 MJ	1.92±0.11	882.7±7.6	0.421±0.015	—	—

See also

• HD 212301
• List of extrasolar planets

References

1. 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. 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.
3. Houk, N. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
4. Stassun, Keivan G.; et al. (March 2017). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal. 153 (3): 20. arXiv:1609.04389. Bibcode:2017AJ....153..136S. doi:10.3847/1538-3881/aa5df3. 136.
5. Bonfanti, A.; et al. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: A5, 14 pp. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297.
6. Delgado Mena, E.; et al. (April 2015), "Li abundances in F stars: planets, rotation, and Galactic evolution", Astronomy & Astrophysics, 576: 24, arXiv:1412.4618, Bibcode:2015A&A...576A..69D, doi:10.1051/0004-6361/201425433, A69
7. "HD 213240". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-27.
8. Mugrauer, M.; et al. (2005). "Four New Wide Binaries Among Exoplanet Host Stars". Astronomy and Astrophysics. 440 (3): 1051–1060. arXiv:astro-ph/0507101. Bibcode:2005A&A...440.1051M. doi:10.1051/0004-6361:20042297.
9. Santos, N. C.; et al. (2001). "The CORALIE survey for southern extra-solar planets VI. New long period giant planets around HD 28185 and HD 213240". Astronomy and Astrophysics. 379 (3): 999–1004. arXiv:astro-ph/0106255. Bibcode:2001A&A...379..999S. doi:10.1051/0004-6361:20011366.
10. Butler, R. P.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701.