HD 203030

HD 203030 is a single orange (K-type) main-sequence , located approximately 128 light-years away in the constellation of Vulpecula, taking its primary name from its Henry Draper Catalogue designation.

HD 203030

HD 203030 location, 0.14 degrees FOV. The star is marked within the red diamond.
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Vulpecula
Right ascension	21^h 18^m 58.2198^s[1]
Declination	26° 13′ 49.9562″[1]
Apparent magnitude (V)	8.426[1]
Characteristics
HD 203030
Evolutionary stage	main sequence star
Spectral type	K0V
B−V color index	0.78
V−R color index	-0.364
Astrometry
Radial velocity (Rv)	-16.651±0.0024[1] km/s
Proper motion (μ)	RA: 133.593±0.108 [1] mas/yr Dec.: 9.563±0.11 [1] mas/yr
Parallax (π)	25.4488 ± 0.061[1] mas
Distance	128.2 ± 0.3 ly (39.29 ± 0.09 pc)
Details
HD 203030
Mass	0.965±0.035[2] M☉
Age	0.1^+0.05 −0.07[3] Gyr
Other designations
HIP 105232, LTT 4041, TYC 2190-1095-1, UBV 18409, 2MASS J21185820+2613500, Gaia DR2 1846882224145757056
Database references
SIMBAD	data
Exoplanet Archive	data
Extrasolar Planets Encyclopaedia	data

History and nomenclature

The designation HD 203030 is from the Henry Draper Catalogue, which is based on spectral classifications made between 1911 and 1915 by Annie Jump Cannon and her co-workers, and was published between 1918 and 1924.

Characteristics

HD 203030 is a Sun-like K-type main-sequence star. It is likely very young, belonging to 45 million years old IC 2391 open cluster.[3]

Planetary system

In 2006, a direct imaging have discovered what was believed to be brown dwarf of spectral class L7.5 at the projected separation 487.1±1.8 AU.[4] The companion was proven to be in the bound orbit by 2014.[2] In 2017, the planetary system reanalysis have indicated what the star HD 203030 is probably very young, and therefore both the primary and the observed companion are less massive than previously thought, placing companion object within planetary definition.[3] In 2019, the rotational period of the HD 203030 B was measured to be equal to 7.5^+0.6
_−0.5 hours, and patchy cloud cover was detected.[5]

The HD 203030 planetary system[3]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
B	11^+4 −3 MJ	487	—	—	—	—

See also

• List of extrasolar planets
• List of directly imaged exoplanets

References

1. HD 203030, entry, SIMBAD. Accessed online June 2, 2020.
2. Ginski, C.; Schmidt, T. O. B.; Mugrauer, M.; Neuhäuser, R.; Vogt, N.; Errmann, R.; Berndt, A. (2014). "Astrometric follow-up observations of directly imaged sub-stellar companions to young stars and brown dwarfs★". Monthly Notices of the Royal Astronomical Society. 444 (3): 2280–2302. arXiv:1409.1850. Bibcode:2014MNRAS.444.2280G. doi:10.1093/mnras/stu1586.
3. Miles-Páez, Paulo A.; Metchev, Stanimir; Luhman, Kevin L.; Marengo, Massimo; Hulsebus, Alan (2017). "The Prototypical Young L/T-Transition Dwarf HD 203030B Likely Has Planetary Mass". The Astronomical Journal. 154 (6): 262. arXiv:1710.11274. Bibcode:2017AJ....154..262M. doi:10.3847/1538-3881/aa9711.
4. Metchev, Stanimir A.; Hillenbrand, Lynne A. (2006). "HD 203030B: An Unusually Cool Young Substellar Companion near the L/T Transition". The Astrophysical Journal. 651 (2): 1166–1176. arXiv:astro-ph/0607514. Bibcode:2006ApJ...651.1166M. doi:10.1086/507836.
5. Miles-Páez, Paulo A.; Metchev, Stanimir; Apai, Dániel; Zhou, Yifan; Manjavacas, Elena; Karalidi, Theodora; Lew, Ben W. P.; Burgasser, Adam J.; Bedin, Luigi R.; Cowan, Nicolas; Lowrance, Patrick J.; Marley, Mark S.; Radigan, Jacqueline; Schneider, Glenn (2019). "Cloud Atlas: Variability in and out of the Water Band in the Planetary-mass HD 203030B Points to Cloud Sedimentation in Low-gravity L Dwarfs". The Astrophysical Journal. 883 (2): 181. arXiv:1908.09403. Bibcode:2019ApJ...883..181M. doi:10.3847/1538-4357/ab3d25.