HD 104985

HD 104985 / Tonatiuh
Observation data
Epoch J2000      Equinox J2000
Constellation Camelopardalis
Right ascension 12h 05m 15.1172s[1]
Declination +76° 54′ 20.643″[1]
Apparent magnitude (V) 5.78[2]
Characteristics
Evolutionary stage Horizontal branch[3]
Spectral type G8.5IIIb[4]
B−V color index 1.029±0.005[2]
Astrometry
Radial velocity (Rv)−20.34(13)[1] km/s
Proper motion (μ) RA: 147.183(40) mas/yr[1]
Dec.: −92.464(41) mas/yr[1]
Parallax (π)9.9280 ± 0.0383 mas[1]
Distance329 ± 1 ly
(100.7 ± 0.4 pc)
Absolute magnitude (MV)0.85[2]
Details[5]
Mass1.22±0.05 M☉
Radius10.64±0.29 R☉
Luminosity51±1[6] L☉
Surface gravity (log g)2.43±0.06 cgs
Temperature4,685±15 K
Metallicity [Fe/H]−0.36±0.02 dex
Age4.39±0.54 Gyr
Other designations
Tonatiuh, BD+77° 461, FK5 451, GC 16514, HD 104985, HIP 58952, HR 4609, SAO 7500, NLTT 29548[3]
Database references
SIMBADdata

HD 104985, formally named Tonatiuh (/toʊnəˈtiːuː/),[7][8] is a solitary[9] star with a exoplanetary companion in the northern constellation of Camelopardalis. The companion is designated HD 104985 b and named Meztli (/ˈmɛstli/). This star has an apparent visual magnitude of 5.78[2] and thus is dimly visible to the naked eye under favorable seeing conditions. It is located at a distance of approximately 329 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −20 km/s.[1]

The stellar classification of this star is G8.5IIIb,[4] indicating this is an evolved giant star that has exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. It is located in the red clump region of the HR diagram, suggesting it is on the horizontal branch and generating energy through core helium fusion.[10] The star is approximately 4.4 billion years old with 1.2 times the mass of the Sun and has expanded to 10.6 times the Sun's radius.[5] It is radiating 51[6] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,730 K.[5]

In 2003, radial velocity measurements made by the Okayama Planet Search Program led to the announcement of an exoplanetary companion.[11] It is orbiting at a distance of 0.95 AU (142 Gm) with a period of 199.5 days with an eccentricity (ovalness) of 0.09. Since the inclination of the exoplanet's orbital plane is unknown, only a lower bound on its mass can be determined. It has at least 8.3 times the mass of Jupiter.[10]

  1. ^ a b c d e f Cite error: The named reference Gaia DR3 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Keenan_McNeil_1989 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Maldonado_Villaver_2016 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Bonfanti_et_al_2016 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference IAU-CSN was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference pronounce was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton_Tokovinin_2008 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Sato2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Sato_et_al_2003 was invoked but never defined (see the help page).