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HD 39194

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HD 39194
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Mensa
Right ascension 05h 44m 31.9180s[1]
Declination −70° 08′ 36.858″[1]
Apparent magnitude (V) 8.07±0.01[2]
Characteristics
Spectral type K0 V[3]
U−B color index +0.26[4][5]
B−V color index +0.76[4][5]
Astrometry
Radial velocity (Rv)13.90±0.10[6] km/s
Proper motion (μ) RA: −309.273 mas/yr[1]
Dec.: +1238.862 mas/yr[1]
Parallax (π)37.8235 ± 0.0206 mas[1]
Distance86.23 ± 0.05 ly
(26.44 ± 0.01 pc)
Absolute magnitude (MV)+6.02[7]
Details
Mass0.71[8] M☉
Radius0.74[9] R☉
Luminosity0.389[10] L☉
Surface gravity (log g)4.61±0.05[11] cgs
Temperature5,205±23[11] K
Metallicity [Fe/H]−0.61±0.02[11] dex
Rotational velocity (v sin i)2[12] km/s
Age11.7[8] Gyr
Other designations
CD−70°340, CPD−70°447, GJ 217.2, HD 39194, HIP 27080, SAO 256232, LHS 210
Database references
SIMBADdata

HD 39194 (Gliese 217.2; LHS 210) is a star located in the southern circumpolar constellation Mensa. It has an apparent magnitude of 8.07,[2] making it readily visible in binoculars but not to the naked eye. The object is relatively close at a distance of 86 light years[1] but is receding with a heliocentric radial velocity of 13.9 km/s.[6]

Characteristics[edit]

HD 39194 has a general stellar classification of K0 V,[3] indicating that it is a K-type main-sequence star. Houk & Cowley found a slightly warmer class of G8 V,[13] instead making it a G-type main-sequence star. Nevertheless, it has 71% the mass of the Sun[8] and an effective temperature of 5,205 K,[11] giving an orange hue. It radius of 0.74 R☉[9] yields a luminosity only 38% that of the Sun.[10] HD 39194 is estimated to be 11.7 billion years old[8] and is extremely chromospherically inactive.[3] Despite being a planetary host, it has an iron abundance only 24% that of the Sun.[11] HD 39194's projected rotational velocity is similar to the Sun's, with the value being 2 km/s.[12]

Planetary system[edit]

Three planet candidates around this star were first reported in a 2011 preprint.[14] After 10 years of observations, a team of astronomers confirmed 3 super-Earths circling HD 39194 in eccentric orbits;[10] none of the planets are in the habitable zone. HD 39194 b and d have similar masses.

This star was selected as a potential candidate for future exoplanet imaging missions in 2015.[9]

The HD 39194 planetary system[10]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥4.13±0.20 M🜨 0.056±0.001 5.6368±0.0004 <0.207 — —
c ≥6.29±0.51 M🜨 0.103±0.002 14.030±0.003 <0.154 — —
d ≥4.13±0.60 M🜨 0.185±0.003 33.91±0.03 <0.333 — —

See also[edit]

References[edit]

  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ^ a b Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
  3. ^ a b c Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2 June 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. eISSN 1538-3881. ISSN 0004-6256.
  4. ^ a b Eggen, O. J. (January 1979). "Catalogs of proper-motion stars. I - Stars brighter than visual magnitude 15 and with annual proper motion of 1 arcsec or more". The Astrophysical Journal Supplement Series. 39: 89. Bibcode:1979ApJS...39...89E. doi:10.1086/190566. eISSN 1538-4365. ISSN 0067-0049.
  5. ^ a b Sandage, Allan; Fouts, Gary (January 1987). "New subdwarfs. VI - Kinematics of 1125 high-proper-motion stars and the collapse of the Galaxy". The Astronomical Journal. 93: 74. Bibcode:1987AJ.....93...74S. doi:10.1086/114291. ISSN 0004-6256.
  6. ^ a b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. ISSN 1063-7737. S2CID 119231169.
  7. ^ 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.
  8. ^ a b c d Luck, R. Earle (13 February 2018). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 111. Bibcode:2018AJ....155..111L. doi:10.3847/1538-3881/aaa9b5. eISSN 1538-3881.
  9. ^ a b c Margaret C Turnbull (2015). "ExoCat-1: The Nearby Stellar Systems Catalog for Exoplanet Imaging Missions". arXiv:1510.01731 [astro-ph.SR].
  10. ^ a b c d Unger, N.; et al. (October 2021). "The HARPS search for southern extra-solar planets". Astronomy & Astrophysics. 654: A104. arXiv:2108.10198. Bibcode:2021A&A...654A.104U. doi:10.1051/0004-6361/202141351. eISSN 1432-0746. ISSN 0004-6361.
  11. ^ a b c d e Sousa, S. G.; Santos, N. C.; Mayor, M.; Udry, S.; Casagrande, L.; Israelian, G.; Pepe, F.; Queloz, D.; Monteiro, M. J. P. F. G. (4 June 2008). "Spectroscopic parameters for 451 stars in the HARPS GTO planet search program". Astronomy & Astrophysics. 487 (1): 373–381. arXiv:0805.4826. Bibcode:2008A&A...487..373S. doi:10.1051/0004-6361:200809698. eISSN 1432-0746. ISSN 0004-6361.
  12. ^ a b Nordström, B.; Mayor, M.; Andersen, J.; Holmberg, J.; Pont, F.; Jørgensen, B. R.; Olsen, E. H.; Udry, S.; Mowlavi, N. (May 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of ~14 000 F and G dwarfs". Astronomy & Astrophysics. 418 (3): 989–1019. arXiv:astro-ph/0405198. Bibcode:2004A&A...418..989N. doi:10.1051/0004-6361:20035959. ISSN 0004-6361.
  13. ^ Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations -90° to -53.0°. Bibcode:1975mcts.book.....H.
  14. ^ Mayor, M.; Marmier, M.; Lovis, C.; Udry, S.; Ségransan, D.; Pepe, F.; Benz, W.; Bertaux, J.-L.; Bouchy, F.; Dumusque, X.; Curto, G. Lo; Mordasini, C.; Queloz, D.; Santos, N. C. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497 [astro-ph.EP].
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