HD 11964

HD 11964 is a binary star system located 110[1] light-years away from the Sun in the equatorial constellation of Cetus. It is visible in binoculars or a telescope but is too faint to be seen with the naked eye, having an apparent visual magnitude of 7.51.[2] The system is drifting closer to the Sun with a radial velocity of −9 km/s.[5] Two extrasolar planets have been confirmed to orbit the primary.

HD 11964
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cetus
Right ascension 01h 57m 09.6074s[1]
Declination −10° 14′ 32.7318″[1]
Apparent magnitude (V) 7.51[2]
Characteristics
Spectral type G9VCN+1[3][2] + M0.0Ve[4]
Apparent magnitude (U) 7.705
Apparent magnitude (B) 8.117[2]
Apparent magnitude (R) 5.960
Apparent magnitude (I) 6.914[2]
Apparent magnitude (J) 6.508±0.019[2]
Apparent magnitude (H) 6.265±0.031[2]
Apparent magnitude (K) 6.168±0.017[2]
U−B color index 0.450
B−V color index 0.607±0.015[2]
V−R color index 0.455
R−I color index 0.405
Variable type Suspected
Astrometry
Radial velocity (Rv)−9.34±0.08[5] km/s
Proper motion (μ) RA: −366.957±0.070[1] mas/yr
Dec.: −242.431±0.052[1] mas/yr
Parallax (π)29.7890 ± 0.0378[1] mas
Distance109.5 ± 0.1 ly
(33.57 ± 0.04 pc)
Absolute magnitude (MV)3.84[2]
Details
A
Mass1.12±0.03[6] M☉
Radius2.234±0.304[7] R☉
Luminosity2.9[6] L☉
Surface gravity (log g)3.94±0.03[5] cgs
Temperature5,321±16[5] K
Metallicity [Fe/H]0.06±0.04[5] dex
Rotational velocity (v sin i)1.52±0.23[5] km/s
Age7.02±0.67[6] Gyr
B
Radius0.60+0.04
−0.03[1] R☉
Luminosity0.085[1] L☉
Temperature4,033+79
−133[1] K
Metallicity [Fe/H]0.12±0.03[8] dex
Other designations
BD−10°403, GC 2351, GJ 81.1, HD 11964, HIP 9094, SAO 148123, WDS 01572-1015[9]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

Properties

The primary, component A, is a G-type main-sequence star with a stellar classification of G9VCN+1.[3] The suffix notation indicates an overabundance of the cyano radical in the spectrum. Houk and Swift (1999) found a class of G8IV, suggesting it is instead a more evolved subgiant star.[10] It is around seven[6] billion years old and is spinning slowly with a projected rotational velocity of 1.5 km/s.[5] The star has 1.1[6] times the mass of the Sun and 2.2[7] times the Sun's radius. It is radiating 2.9[6] times the luminosity of the Sun from its photosphere at an effective temperature of 5,321 K.[5]

A wide binary companion star was discovered in 2000.[11] This secondary, designated component B, has a visual magnitude of 11.11 and lies at an angular separation of 29.7″ along a position angle of 134°, as of 2015.[12] It is a red dwarf with a class of M0V,[4] and has just 0.6 times the Sun's radius. It is radiating 0.085 times the Sun's luminosity at an effective temperature of 4,033 K.[1]

Planetary system

In August 2005, two planets were discovered orbiting the star, the innermost like Neptune and another like Jupiter orbiting at 3.34 AU. However, the second planet (HD 11964 b) was not confirmed until May 2007. In September 2007, P.C. Gregory claimed that there was a third planet in the system on the basis of Bayesian analysis of the radial velocity data. The planet was claimed to have a mass similar to that of Saturn and located in a 360-day orbit. Gregory cautioned that the close match between the period of this planet to being exactly a year meant that the radial velocity variations may have been caused by insufficient correction for the motion of the Earth in orbit around the Sun.[13] The planet was not detected in re-reduced data in an analysis published in the Astrophysical Journal in 2009.[14]

The HD 11964 planetary system[14]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
c ≥ 0.11 MJ 0.229 37.82 0.15 — —
b ≥ 0.61±0.1 MJ 3.34±0.4 2,110±70 0.06±0.2 — —

See also
  • HD 11977
  • 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 records 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. 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. Alonso-Floriano, F. J.; et al. (2015). "CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS". Astronomy and Astrophysics. 577: A128. arXiv:1502.07580. Bibcode:2015A&A...577A.128A. doi:10.1051/0004-6361/201525803. S2CID 53135130.
  5. Jofré, E.; et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931.
  6. Ghezzi, L.; et al. (December 2010), "Metallicities of Planet-hosting Stars: A Sample of Giants and Subgiants", The Astrophysical Journal, 725 (1): 721–733, arXiv:1008.3539, Bibcode:2010ApJ...725..721G, doi:10.1088/0004-637X/725/1/721, S2CID 119206634
  7. van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. S2CID 18370219.
  8. Mann, Andrew W.; et al. (February 2013). "Prospecting in Late-type Dwarfs: A Calibration of Infrared and Visible Spectroscopic Metallicities of Late K and M Dwarfs Spanning 1.5 dex". The Astronomical Journal. 145 (2): 15. arXiv:1211.4630. Bibcode:2013AJ....145...52M. doi:10.1088/0004-6256/145/2/52. S2CID 118481247. 52.
  9. "HD 11964". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-12.
  10. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  11. Allen, C.; et al. (2000). "Wide binaries among high-velocity and metal-poor stars". Astronomy and Astrophysics. 356 (2): 529–540. Bibcode:2000A&A...356..529A.
  12. Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Retrieved 2015-07-22.
  13. Gregory, P. C. (2007). "A Bayesian periodogram finds evidence for three planets in HD 11964". Monthly Notices of the Royal Astronomical Society. 381 (4): 1607–1616. arXiv:0709.0970. Bibcode:2007MNRAS.381.1607G. doi:10.1111/j.1365-2966.2007.12361.x. S2CID 16796923.
  14. Wright, J. T.; et al. (2009). "Ten New and Updated Multi-planet Systems, and a Survey of Exoplanetary Systems". The Astrophysical Journal. 693 (2): 1084–1099. arXiv:0812.1582. Bibcode:2009ApJ...693.1084W. doi:10.1088/0004-637X/693/2/1084. S2CID 18169921.

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