HD 100777 / Sagarmatha
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 11h 35m 51.5230s[1]
Declination −04° 45′ 20.5012″[1]
Apparent magnitude (V) 8.42[2]
Characteristics
Spectral type G8V[3]
B−V color index 0.76±0.02[2]
Astrometry
Proper motion (μ) RA: −11.353±0.111[1] mas/yr
Dec.: 35.358±0.061[1] mas/yr
Parallax (π)20.1596 ± 0.0589 mas[1]
Distance161.8 ± 0.5 ly
(49.6 ± 0.1 pc)
Absolute magnitude (MV)4.95[2]
Details[4]
Mass1.032+0.042
−0.045 M☉
Radius1.033+0.021
−0.018 R☉
Luminosity0.946+0.003
−0.004[1] L☉
Surface gravity (log g)4.402±0.265 cgs
Temperature5,611±42 K
Metallicity [Fe/H]0.330±0.096 dex
Rotational velocity (v sin i)1.676±0.230 km/s
Age4.78+2.20
−2.14 Gyr
Other designations
BD–03°3147, HD 100777, HIP 56572, SAO 138288, TYC 4933-678-1, 2MASS J11355152-0445204[5]
Database references
SIMBADdata

HD 100777 is a single[6] star with a planetary companion in the equatorial constellation of Leo.[7] With an apparent visual magnitude of 8.42 it is too faint to be viewed with the naked eye, although the absolute magnitude of 4.81 indicates it could be seen if it were just 33 ly (10 pc) away. The distance to the star is approximately 162 light years based on parallax measurements.

The International Astronomical Union held the NameExoWorlds campaign in 2019. Nepal named the star Sagarmatha("similar to Nepali name of the Mt. Everest") and the exoplanet revolving it was named as Laligurans, the Nepali name of the flower Rhododendron.[8]

This is an ordinary G-type main-sequence star with a stellar classification of G8V.[3] It has a similar mass, size, and luminosity to the Sun. The star is roughly five[4] billion years old with an inactive chromosphere[7] and is spinning with a projected rotational velocity of 1.7 km/s.[4] A 2015 survey ruled out the existence of any additional stellar companions at projected distances from 18 to 369 astronomical units.[6]

Planetary system

In 2007, a giant exoplanet companion was found using the radial velocity method. It is orbiting HD 100777 at a distance of 1.03 AU with a period of 384 days and an eccentricity (ovalness) of 0.36. The inclination of the orbital plane of this body is unknown, so only a lower limit on the mass can be determined. It has at least 1.16 times the mass of Jupiter.[7]

The HD 100777 planetary system[7]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Laligurans >1.16 ± 0.03 MJ 1.03 ± 0.03 383.7 ± 1.2 0.36 ± 0.02 — —

See also

References

  1. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data 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 source at VizieR.
  2. 1 2 3 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.
  3. 1 2 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. 1 2 3 Soto, M. G.; Jenkins, J. S. (2018). "Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars (SPECIES). I. Code description and dwarf stars catalogue". Astronomy and Astrophysics. 615: A76. arXiv:1801.09698. Bibcode:2018A&A...615A..76S. doi:10.1051/0004-6361/201731533. S2CID 119107228.
  5. ↑ "HD 100777". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-08.
  6. 1 2 Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340. Retrieved 19 June 2020.
  7. 1 2 3 4 Naef, M.; et al. (2007). "The HARPS search for southern extra-solar planets. IX. Exoplanets orbiting HD 100777, HD 190647, and HD 221287". Astronomy and Astrophysics. 470 (2): 721–726. arXiv:0704.0917. Bibcode:2007A&A...470..721N. doi:10.1051/0004-6361:20077361.
  8. ↑ "Approved names". NameExoworlds. Retrieved 2020-01-02.
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