Astronomy:HD 65216

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Short description: Triple star-system in the constellation Carina
HD 65216
Observation data
Equinox J2000.0]] (ICRS)
Constellation Carina
Right ascension  07h 53m 41.3193s[1]
Declination −63° 38′ 50.353″[1]
Apparent magnitude (V) 7.97[2]
Characteristics
Spectral type G5V[3] + M7–8 + L2–3[4]
B−V color index 0.672±0.012[2]
Astrometry
Radial velocity (Rv)42.57±0.16[1] km/s
Proper motion (μ) RA: −123.633±0.065[1] mas/yr
Dec.: 146.578±0.073[1] mas/yr
Parallax (π)28.4445 ± 0.0317[1] mas
Distance114.7 ± 0.1 ly
(35.16 ± 0.04 pc)
Absolute magnitude (MV)5.22[2]
Details
HD 65216 A
Mass0.95±0.01[5] M
Radius0.864±0.003[5] R
Luminosity0.716±0.001[5] L
Surface gravity (log g)4.53±0.01[5] cgs
Temperature5,718±8[5] K
Metallicity [Fe/H]−0.17[6] dex
Rotational velocity (v sin i)1.308[6] km/s
Age1.7±0.5[5] Gyr
Other designations
CD−63°359, HD 65216, HIP 38558, SAO 250002, WDS J07537-6339A[7]
Database references
SIMBADdata

HD 65216 is a triple[4] star system with two exoplanetary companions in the southern constellation of Carina. With an apparent visual magnitude of 7.97[2] it cannot be readily seen without technical aid, but with binoculars or telescope it should be visible. The system is located at a distance of 114.7 light-years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 42.6 km/s.[1]

The primary, component A, is an ordinary G-type main-sequence star with a stellar classification of G5V.[3] It is nearly two billion years old[5] and is spinning with a projected rotational velocity of 1.3 km/s.[6] The star has 95% of the mass and 86% of the radius of the Sun. It is radiating 72% of the luminosity of the Sun from its photosphere at an effective temperature of 5,718 K.[5]

In 2008 a co-moving binary system of low mass companions were discovered at an angular separation of 7 from the primary, which is equivalent to a projected separation of 253 astronomical unit|AU at the distance of HD 65216. Component B is of class M7–8 (0.089 M) while component C is class L2–3 (0.078 M); both have a mass close to the sub-stellar limit. The pair have a projected separation of 6 AU from each other.[4]

Planetary system

An extrasolar planet (designated as HD 65216 b) was discovered orbiting the primary in 2003.[8] A second much more distant planet was suspected since 2013,[9] but was discovered on a completely different orbit in 2019.[10]

The HD 65216 planetary system[10]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ≥1.295±0.062 MJ 1.301±0.020 577.6±1.328 0.27±0.02
c ≥2.03±0.11 MJ 5.75±0.09 5370±20 0.17±0.04

See also

  • List of extrasolar planets

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. 1. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode1978mcts.book.....H. 
  4. 4.0 4.1 4.2 Mugrauer, M.; Seifahrt, A.; Neuhäuser, R. (July 2007). "The multiplicity of planet host stars - new low-mass companions to planet host stars". Monthly Notices of the Royal Astronomical Society 378 (4): 1328–1334. doi:10.1111/j.1365-2966.2007.11858.x. Bibcode2007MNRAS.378.1328M. 
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Bonfanti, A. et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics 575: A18. doi:10.1051/0004-6361/201424951. Bibcode2015A&A...575A..18B. https://www.aanda.org/articles/aa/full_html/2015/03/aa24951-14/aa24951-14.html. 
  6. 6.0 6.1 6.2 Costa Silva, A. R. et al. (February 2020). "Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur". Astronomy & Astrophysics 634: 10. doi:10.1051/0004-6361/201936523. A136. Bibcode2020A&A...634A.136C. 
  7. "HD 65216". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+65216. 
  8. Mayor, M. et al. (2004). "The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE". Astronomy and Astrophysics 415 (1): 391–402. doi:10.1051/0004-6361:20034250. Bibcode2004A&A...415..391M. https://www.aanda.org/articles/aa/full/2004/07/aa0250/aa0250.html. 
  9. Wittenmyer, Robert A. et al. (2013). "Forever Alone? Testing Single Eccentric Planetary Systems for Multiple Companions". The Astrophysical Journal Supplement Series 208 (1): 2. doi:10.1088/0067-0049/208/1/2. Bibcode2013ApJS..208....2W. 
  10. 10.0 10.1 Wittenmyer, Robert A. et al. (2019). "Truly eccentric – I. Revisiting eight single-eccentric planetary systems". Monthly Notices of the Royal Astronomical Society 484 (4): 5859–5867. doi:10.1093/mnras/stz290. Bibcode2019MNRAS.484.5859W. 

External links

Coordinates: Sky map 07h 53m 41.3223s, −63° 38′ 50.363″