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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, making it readily visible in binoculars but not to the naked eye. The object is relatively close at a distance of 86 light years but is receding with a heliocentric radial velocity of 13.9 km/s.

Characteristics

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

Planetary system

Three planet candidates around this star were first reported in a 2011 preprint. After 10 years of observations, a team of astronomers confirmed 3 super-Earths circling HD 39194 in eccentric orbits; 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.

See also

• List of multiplanetary systems
• Pi Mensae, another exoplanet-hosting star in the same constellation.

References

1. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ Margaret C Turnbull (2015). "ExoCat-1: The Nearby Stellar Systems Catalog for Exoplanet Imaging Missions". arXiv:1510.01731 .
10. ^ 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. ^ 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. ^ 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 .

v t e Constellation of Mensa
List of stars in Mensa
Stars	Bayer α β γ δ ε ζ η θ ι κ λ μ ν ξ π Variable W TU TY TZ UX YY AH AO HR 1109 1154 1531 1606 1682 1700 HD 35184 38283 (Bubup) 39194 42936 268835 Other OGLE-LMC-CEP0227 R71 WISE 0535−7500
Exoplanets π Mensae b c d HD 38283 b (Yanyan)
Star clusters NGC 1943 NGC 1959 NGC 1986 NGC 1987 NGC 2000
Nebulae Henize 206 NGC 2122
Galaxies	NGC 2012 2144 Other Large Magellanic Cloud (mostly in Dorado, partly in Hydrus) PKS 0637-752
Category

• K-type main-sequence stars
• Planetary systems with three confirmed planets
• Mensa (constellation)
• Henry Draper Catalogue objects
• Hipparcos objects
• Gliese and GJ objects
• Durchmusterung objects