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]
| 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] |
| Distance | 86.23 ± 0.05 ly (26.44 ± 0.01 pc) |
| Absolute magnitude (MV) | 6.02[7] |
| Details | |
| Mass | 0.71[8] M☉ |
| Radius | 0.74[9] R☉ |
| Luminosity | 0.389[10] L☉ |
| Surface gravity (log g) | 4.61±0.05[11] cgs |
| Temperature | 5,205±23[11] K |
| Metallicity [Fe/H] | −0.61±0.02[11] dex |
| Rotational velocity (v sin i) | 2[12] km/s |
| Age | 11.7[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Characteristics
editHD 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
editThree 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]
| 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- List of multiplanetary systems
- Pi Mensae, another exoplanet-hosting star in the same constellation.
References
edit- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ a b c Margaret C Turnbull (2015). "ExoCat-1: The Nearby Stellar Systems Catalog for Exoplanet Imaging Missions". arXiv:1510.01731 [astro-ph.SR].
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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].