Astronomy:HIP 79431

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HIP 79431 / Sharjah
Observation data
Equinox J2000.0]] (ICRS)
Constellation Scorpius
Right ascension  16h 12m 41.780s[1]
Declination −18° 52′ 31.81″[1]
Apparent magnitude (V) 11.34[2]
Characteristics
Spectral type M3V[3]
Apparent magnitude (B) 12.826[2]
Apparent magnitude (R) 10.46[2]
Apparent magnitude (I) 9.370[2]
Apparent magnitude (J) 7.555±0.026[2]
Apparent magnitude (H) 6.855±0.044[2]
Apparent magnitude (K) 6.589±0.018[2]
B−V color index 1.486±0.011[2]
V−R color index 0.88[2]
R−I color index 1.09[2]
Astrometry
Radial velocity (Rv)−4.66±0.28[4] km/s
Proper motion (μ) RA: 35.707[1] mas/yr
Dec.: −214.050[1] mas/yr
Parallax (π)68.7833 ± 0.1217[1] mas
Distance47.42 ± 0.08 ly
(14.54 ± 0.03 pc)
Absolute magnitude (MV)10.55[2]
Details
Mass0.49±0.05 M☉[5]
0.445 M☉[6]
0.466[7] M☉
Radius0.54±0.02 R☉[8]
0.391 R☉[6]
0.442[7] R☉
Surface gravity (log g)4.86 cgs[6]
4.815[7] cgs
Temperature3,689±20[9] K
Metallicity [Fe/H]+0.46±0.17[9] dex
Other designations
Sharjah, HIP 79431, LP 804-27, NLTT 42226[10]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data
Short description: Red dwarf star in the constellation Scorpius

HIP 79431 is a red dwarf star with a planetary companion in the constellation Scorpius. It has the proper name Sharjah, as selected in the NameExoWorlds campaign by United Arab Emirates, during the 100th anniversary of the IAU. Sharjah is the cultural capital of United Arab Emirates.[11][12] The star has an apparent visual magnitude of 11.34,[2] which is far too faint to be visible to the naked eye. Based on parallax measurements, this system is located at a distance of 47.4 light-years from the Sun. It is drifting closer with a radial velocity of −5 km/s.[4]

This is an M-type main-sequence star with a stellar classification of M3V.[3] This star is smaller, cooler, dimmer, and less massive than the Sun, but the estimated metal content is 2.5 times as much as the Sun. The level of chromospheric activity does not appear to be unusually high for a star of this class.[9]

In 2010, a superjovian exoplanetary companion was discovered using the radial-velocity method. It is orbiting at a distance of 0.36 astronomical unit|AU from the hos star with a period of 0.3 years and an eccentricity (ovalness) of 0.29. Since the inclination of the orbit is unknown, only a lower bound on the mass can be determined. It has at least 2.1 times the mass of Jupiter.[5]

The HIP 79431 planetary system[5]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b / Barajeel ≥2.1 MJ 0.36 111.7 ± 0.7 0.29 ± 0.02 — —

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  3. ↑ 3.0 3.1 Gray, R. O. et al. (July 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. doi:10.1086/504637. Bibcode: 2006AJ....132..161G. 
  4. ↑ 4.0 4.1 Terrien, Ryan C. et al. (March 2015). "M Dwarf Luminosity, Radius, and α-enrichment from I-band Spectral Features". The Astrophysical Journal Letters 802 (1): 6. doi:10.1088/2041-8205/802/1/L10. L10. Bibcode: 2015ApJ...802L..10T. 
  5. ↑ 5.0 5.1 5.2 Apps, Kevin et al. (2010). "M2K: I. A Jupiter-Mass Planet Orbiting the M3V Star HIP 79431". Publications of the Astronomical Society of the Pacific 122 (888): 156–161. doi:10.1086/651058. Bibcode: 2010PASP..122..156A. http://www.journals.uchicago.edu/doi/abs/10.1086/651058. 
  6. ↑ 6.0 6.1 6.2 Doyle, L. et al. (October 2018). "Investigating the rotational phase of stellar flares on M dwarfs using K2 short cadence data". Monthly Notices of the Royal Astronomical Society 480 (2): 2153–2164. doi:10.1093/mnras/sty1963. Bibcode: 2018MNRAS.480.2153D. 
  7. ↑ 7.0 7.1 7.2 Tsuji, Takashi; Nakajima, Tadashi (October 2014). "Near-infrared spectroscopy of M dwarfs. I. CO molecule as an abundance indicator of carbon†". Publications of the Astronomical Society of Japan 66 (5): 26. doi:10.1093/pasj/psu078. 98. Bibcode: 2014PASJ...66...98T. 
  8. ↑ Stassun, Keivan G. et al. (2016). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal 153 (3): 136. doi:10.3847/1538-3881/aa5df3. Bibcode: 2017AJ....153..136S. 
  9. ↑ 9.0 9.1 9.2 Rojas-Ayala, Bárbara et al. (April 2012), "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs", The Astrophysical Journal 748 (2): 93, doi:10.1088/0004-637X/748/2/93, Bibcode: 2012ApJ...748...93R 
  10. ↑ "LP 804-27". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=LP+804-27. 
  11. ↑ "Approved names" (in en). http://www.nameexoworlds.iau.org/final-results. 
  12. ↑ "International Astronomical Union | IAU". https://www.iau.org/news/pressreleases/detail/iau1912/. 

Coordinates: Sky map 16h 12m 41.77s, −1852° 31.8′ 49″



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