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HD 38858

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HD 38858
Observation data
EpochJ2000.0EquinoxJ2000.0
Constellation Orion
Right ascension 05h48m34.93996s[1]
Declination −04° 05′ 40.7153″[1]
Apparent magnitude(V) +5.97[2]
Characteristics
Spectral type G4V[3]
U−Bcolor index +0.10[2]
B−Vcolor index +0.64[2]
Astrometry
Radial velocity(Rv)+31.2[4]km/s
Proper motion(μ)RA:60.84 ± 0.41[1]mas/yr
Dec.:–228.35 ± 0.33[1]mas/yr
Parallax(π)65.89 ± 0.41mas[1]
Distance49.5 ± 0.3ly
(15.18 ± 0.09pc)
Details
Mass0.886[5]M☉
Radius0.9331 ± 0.0162[5]R☉
Luminosity0.7943 ± 0.0101[5]L☉
Surface gravity(logg)4.36 ± 0.06[3]cgs
Temperature5,660 ± 20[3]K
Metallicity[Fe/H]–0.27 ± 0.03[3]dex
Rotational velocity(vsini)2.61[6]km/s
Age6.2[7]Gyr
Other designations
BD–04 1244,FK51155,GJ1085,HD38858,HIP27435,LTT2380,SAO132554,2MASS.
Database references
SIMBADdata
Exoplanet Archivedata

HD 38858is aG-type star,[3]much likeThe Sun,with one detected planet. The planet, designatedHD 38858 b,is about twice the mass ofUranusand orbits in the star'shabitable zone.[8]

The last observation of this system for a dust disc or comet belt was in 2009 by theSpitzer Space Telescope;a belt was inferred at 102 AU.[7]It has an inclination of 48◦.[9]

The star exhibit a magnetic activity cycle remarkably similar to that of Sun, with the period of 10.8 years.[10]

Planetary system

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The exoplanet HD 38858 b was discovered in 2011 in orbit in its host star's habitable zone, a zone in which Earth-like conditions (namely the presence of liquid water) on a planet's surface are possible.[11][12]The planet is likely agas giant,a type of planet whichastronomersbelieve is unlikely to supportlifeas it is currently understood. However, the planet could have arockynatural satellitecapable of sustaining an Earth-like environment.[13]In 2020, the issue of habitability was explored by the popularYouTubechannel "Fire of Learning", in which the planet was referred to as "Kynigos", and its hypothetical satellite was compared to theJovian MoonsofEuropaandIo.Potential obstacles to habitability of any natural satellite, including theeccentricityof the planet's orbit, likelihood of the moon beingtidally locked,and probable prevalence ofgeothermic activityowed to its orbit around the gas giant, were highlighted.[14][15][16]

The existence of this planet was disputed since 2015 though, attributing the planetary signal to thefrequency-domain aliasof the star magnetic activity cycle, although the existence of another planet on the 198-day orbit is suspected.[10]

The HD 38858 planetary system[17]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b(disputed[10]) 32[18]M🜨 1.0376 ± 0.0189 407.15 ± 4.2857 0.27 ± 0.17 — —
Disk 102–102AU — —

References

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  1. ^abcdevan Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction".Astronomy and Astrophysics.474(2): 653–664.arXiv:0708.1752.Bibcode:2007A&A...474..653V.doi:10.1051/0004-6361:20078357.S2CID18759600.Vizier catalog entry
  2. ^abcJohnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars".Communications of the Lunar and Planetary Laboratory.4(99): 99.Bibcode:1966CoLPL...4...99J.
  3. ^abcdeJ. Maldonado; C. Eiroa; E. Villaver; B. Montesinos; A. Mora (2012). "Metallicity of solar-type stars with debris discs and planets".Astronomy & Astrophysics.541:A40.arXiv:1202.5884.Bibcode:2012A&A...541A..40M.doi:10.1051/0004-6361/201218800.S2CID46328823.
  4. ^Nordström, B.; et al. (May 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs".Astronomy and Astrophysics.418(3): 989–1019.arXiv:astro-ph/0405198.Bibcode:2004A&A...418..989N.doi:10.1051/0004-6361:20035959.S2CID11027621.
  5. ^abcBoyajian, Tabetha S.; et al. (July 2013), "Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations",The Astrophysical Journal,771(1): 40,arXiv:1306.2974,Bibcode:2013ApJ...771...40B,doi:10.1088/0004-637X/771/1/40,S2CID14911430.
  6. ^Martínez-Arnáiz, R.; et al. (September 2010)."Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter"(PDF).Astronomy and Astrophysics.520:A79.arXiv:1002.4391.Bibcode:2010A&A...520A..79M.doi:10.1051/0004-6361/200913725.S2CID43455849.Archived fromthe original(PDF)on 2017-09-22.Retrieved2018-11-04.
  7. ^abWyatt, M. C.; et al. (2012)."Herschel imaging of 61 Vir: implications for the prevalence of debris in low-mass planetary systems".Monthly Notices of the Royal Astronomical Society.424(2): 1206.arXiv:1206.2370.Bibcode:2012MNRAS.424.1206W.doi:10.1111/j.1365-2966.2012.21298.x.S2CID54056835.citing Lawleret al.2009, and recalculating its distance.
  8. ^LTT 2380 -- High proper-motion Star,SIMBAD Astronomical Database, accessed 11 October 2012.
  9. ^Brydenet al.,promised inJohn E. Krist; Karl R. Stapelfeldt; Geoffrey Bryden; Peter Plavchan (2012), "Hubble Space Telescope Observations of the HD 202628 Debris Disk",Astronomical Journal,144(2): 45,arXiv:1206.2078,Bibcode:2012AJ....144...45K,doi:10.1088/0004-6256/144/2/45,S2CID40040285
  10. ^abcFlores, M.; González, J. F.; Jaque Arancibia, M.; Saffe, C.; Buccino, A.; López, F. M.; Ibañez Bustos, R. V.; Miquelarena, P. (2018), "HD 38858: A solar-type star with an activity cycle of ~10.8 yr",Astronomy & Astrophysics,620:A34,arXiv:1809.05581,doi:10.1051/0004-6361/201833330,S2CID126153522
  11. ^"The Extrasolar Planet Encyclopaedia — HD 38858 b".Extrasolar Planets Encyclopaedia.Retrieved2020-03-06.
  12. ^Cain, Fraser (2015-06-29)."What is the Habitable Zone?".Universe Today.Retrieved2020-03-06.
  13. ^"Should We Look For Life on Gas-Giants?".Futurism.Retrieved2020-03-06.
  14. ^"HD 38858".exoplanetarchive.ipac.caltech.edu.Retrieved2020-03-06.
  15. ^"Io's Alien Volcanoes | Science Mission Directorate".science.nasa.gov.Retrieved2020-03-06.
  16. ^March 2018, Elizabeth Howell 22 (22 March 2018)."Europa: Facts About Jupiter's Icy Moon and Its Ocean".Space.com.Retrieved2020-03-06.{{cite web}}:CS1 maint: numeric names: authors list (link)
  17. ^"hd_38858_b".Extrasolar Planets Encyclopaedia.2015.
  18. ^Wyatt; m sin i is 0.0961 ± 0.012 MJ/ 30.55 ± 4.11 (which Wyatt knew from most current cited paper Mayor, "HARPS XXXIV", 2011). Wyatt has likely factored in the inclination but did not state this outright in the arXiv version of the paper.


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