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HD 34445

Coordinates:Sky map05h17m40.9786s,+07° 21′ 12.036″
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HD 34445
Observation data
EpochJ2000.0EquinoxJ2000.0
Constellation Orion
Right ascension 05h17m40.9804s[1]
Declination +07° 21′ 12.0548″[1]
Apparent magnitude(V) 7.31±0.03[2]
Characteristics
Spectral type G0 V[2]
B−Vcolor index 0.661 ± 0.015[2]
Astrometry
Radial velocity(Rv)−78.906±0.0082[3]km/s
Proper motion(μ)RA:−0.811±0.076[1]mas/yr
Dec.:−146.997±0.061[1]mas/yr
Parallax(π)21.6675 ± 0.0464mas[1]
Distance150.5 ± 0.3ly
(46.15 ± 0.10pc)
Absolute magnitude(MV)4.04±0.10[2]
Details
Mass1.07±0.02[2]M☉
Radius1.38±0.08[2]R☉
Luminosity2.01 ± 0.2[2]L☉
Surface gravity(logg)4.21 ± 0.08[2]cgs
Temperature5836 ± 44[2]K
Metallicity[Fe/H]+0.14±0.04 dex[2]
+0.24±0.04[4]dex
Rotation~22 d,[5]~52 d[6]
Rotational velocity(vsini)2.7±0.5[2]km/s
Age8.5±2.0[2]Gyr
Other designations
BD+07° 855,HD34445,HIP24681,SAO112601[7]
Database references
SIMBADdata
Exoplanet Archivedata

HD 34445is astarin theequatorialconstellationofOrion.With anapparent visual magnitudeof 7.31,[2]it is a 7th magnitude star that is too dim to be readily visible to the naked eye. The system is located at a distance of 150.5light yearsfrom theSunbased onparallaxmeasurements, but is drifting closer with a highradial velocityof −79 km/s.[3]It is expected to draw as close as 57.5 light-years in ~492,000 years.[8]

This is an ordinaryG-type main-sequence starwith astellar classificationof G0 V,[2]which means it is a Sun-like star that is generating energy throughcorehydrogen fusion.It is considered a metal-rich star,[4]showing a much highermetallicitycompared to the Sun. Despite this it is an older star andchromospherically quiet,lying about 0.8 magnitudes above themain sequence.This star is larger, hotter, brighter, and more massive than the Sun. It is spinning with aprojected rotational velocityof ~3 km/s, giving it a rotation period of around 22 days.[2]

Planetary companions

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In 2004, agas giantwas found in orbit around the star, but it was not until 2009 that this planet was confirmed.[5]In 2017, five more planets were found.[2]All haveminimum massessignificantly greater than that of theEarth,between 16.8MEand 200.0ME.[2]The system as configured appears to be dynamically stable.[9]

A 2021 study was only able to confirm HD 34445 b as a planet. HD 34445 e was found to likely be an artifact of the stellar rotation, as its orbital period closely matched toe rotation period of the star, HD 34445 c & d were also found to likely be false positives having orbital periods of around1⁄4and1⁄3of a year, and HD 34445 f was not detected.[6]

The HD 34445 planetary system[2]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
e(unconfirmed) ≥0.0529 ± 0.0089MJ 0.2687 ± 0.0019 49.175 ± 0.045 0.090 ± 0.062 — —
d(unconfirmed) ≥0.097 ± 0.13MJ 0.4817 ± 0.0033 117.87 ± 0.18 0.027 ± 0.051 — —
c(unconfirmed) ≥0.168 ± 0.016MJ 0.7181 ± 0.0049 214.67 ± 0.45 0.036 ± 0.071 — —
f(unconfirmed) ≥0.119 ± 0.021MJ 1.543 ± 0.016 676.8 ± 7.9 0.031 ± 0.057 — —
b ≥0.629 ± 0.028MJ 2.075 ± 0.016 1056.7 ± 4.7 0.014 ± 0.035 — —
g(unconfirmed) ≥0.38 ± 0.13MJ 6.36 ± 1.02 5700 ± 1500 0.032 ± 0.080 — —

See also

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References

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  1. ^abcdeBrown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
  2. ^abcdefghijklmnopqrVogt, Steven S.; et al. (2017)."A Six-planet System around the Star HD 34445".The Astronomical Journal.154(5): 181.arXiv:1710.07337.Bibcode:2017AJ....154..181V.doi:10.3847/1538-3881/aa8b61.S2CID119182115.
  3. ^abSoubiran, C.; et al. (2013). "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release".Astronomy and Astrophysics.552.A64.arXiv:1302.1905.Bibcode:2013A&A...552A..64S.doi:10.1051/0004-6361/201220927.S2CID56094559.
  4. ^abSousa, S. G.; et al. (November 2006)."Spectroscopic parameters for a sample of metal-rich solar-type stars".Astronomy and Astrophysics.458(3): 873–880.Bibcode:2006A&A...458..873S.doi:10.1051/0004-6361:20065658.
  5. ^abHoward, Andrew W.; et al. (2010). "The California Planet Survey. I. Four New Giant Exoplanets".The Astrophysical Journal.721(2): 1467–1481.arXiv:1003.3488.Bibcode:2010ApJ...721.1467H.doi:10.1088/0004-637X/721/2/1467.S2CID14147776.
  6. ^abRosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C.; Petigura, Erik A.; Knutson, Heather A.; Behmard, Aida; Chontos, Ashley; Crepp, Justin R.; Crossfield, Ian J. M.; Dalba, Paul A.; Fischer, Debra A.; Henry, Gregory W.; Kane, Stephen R.; Kosiarek, Molly; Marcy, Geoffrey W.; Rubenzahl, Ryan A.; Weiss, Lauren M.; Wright, Jason T. (2021)."The California Legacy Survey. I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades".The Astrophysical Journal Supplement Series.255(1): 8.arXiv:2105.11583.Bibcode:2021ApJS..255....8R.doi:10.3847/1538-4365/abe23c.S2CID235186973.
  7. ^"HD 34445".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved19 November2017.
  8. ^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.S2CID119257644.
  9. ^Georgakarakos, Nikolaos; Dobbs-Dixon, Ian (September 2019)."Do the planets in the HD 34445 system really exist?".Monthly Notices of the Royal Astronomical Society.488(3): 3818–3825.arXiv:1907.05495.Bibcode:2019MNRAS.488.3818G.doi:10.1093/mnras/stz1945.


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