Astronomy:HD 203030
 HD 203030 location, 0.14 degrees FOV. The star is marked within the red diamond. | |
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Vulpecula |
| Right ascension | 21h 18m 58.220s[1] |
| Declination | 26° 13′ 49.96″[1] |
| Apparent magnitude (V) | 8.45[2] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | K0V[3] |
| B−V color index | 0.750±0.015[2] |
| Variable type | BY Dra[4] |
| Astrometry | |
| Radial velocity (Rv) | −16.92±0.26[5] 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 ± 0.0610[1] mas |
| Distance | 128.2 ± 0.3 ly (39.29 ± 0.09 pc) |
| Absolute magnitude (MV) | 5.436±0.030[6] |
| Details | |
| Mass | 0.965±0.035[7] M☉ |
| Radius | 0.86+0.02−0.03[5] R☉ |
| Luminosity | 0.593±0.002[5] L☉ |
| Surface gravity (log g) | 4.64+0.03 −0.01[8] cgs |
| Temperature | 5,603+10 −8[8] K |
| Metallicity [Fe/H] | 0.06±0.07 dex 0.30+0.02 −0.01[8] dex |
| Rotational velocity (v sin i) | 5.62+0.13 −0.14[8] km/s |
| Age | 100+50−70[9] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
HD 203030, also known as V457 Vulpeculae, is a single, yellow-orange hued star with a sub-stellar companion in the northern constellation of Vulpecula. 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. This star is invisible to the naked eye, having an apparent visual magnitude of 8.45.[2] It is located at a distance of 128 light years from the Sun based on parallax,[1] and is drifting closer with a radial velocity of −17 km/s.[5]
The stellar classification of HD 203030 is K0V,[3] indicating this is a K-type main-sequence star.[3] It is likely very young, belonging to the 45 million years old IC 2391 open cluster.[9] Based on photometric measurements by Hipparcos, it was found to exhibit low amplitude periodic variability with a range of 0.0139 in magnitude and a period of 4.14 days.[12] However the General Catalog of Variable Stars lists its period as 6.664 days.[4] It is now classified as a chromospherically active BY Draconis variable.[4] The star has 97%[7] of the mass of the Sun and 86%[5] of the Sun's radius. It is radiating 59%[5] of the luminosity of the Sun from its photosphere at an effective temperature of 5,603 K.[8]
Planetary system
In 2006, direct imaging found co-moving companion at a projected separation of 487.1±1.8 astronomical unit|AU, suggesting this is a candidate brown dwarf of spectral class L7.5.[13] It was shown to be in a bound orbit around the star by 2014.[7] In 2017, a reanalysis indicated that the star HD 203030 is probably very young, and therefore both the primary and the observed companion are less massive than previously thought. This places the companion object at the planetary mass boundary.[9] In 2019, the rotational period of HD 203030 B was measured as 7.5+0.6−0.5 hours, and a patchy cloud cover was detected.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| B | 11+4−3 MJ | 487 | — | — | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A
- ↑ 3.0 3.1 3.2 Frasca, A. et al. (May 1, 2018). "A spectroscopic survey of the youngest field stars in the solar neighborhood . II. The optically faint sample". Astronomy and Astrophysics 612: A96. doi:10.1051/0004-6361/201732028. ISSN 0004-6361. Bibcode: 2018A&A...612A..96F.
- ↑ 4.0 4.1 4.2 Samus, N. N. et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1 61 (1): 80–88. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 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.
- ↑ 6.0 6.1 Miles-Páez, Paulo A. et al. (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. doi:10.3847/1538-4357/ab3d25. Bibcode: 2019ApJ...883..181M.
- ↑ 7.0 7.1 7.2 Ginski, C. et al. (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. doi:10.1093/mnras/stu1586. Bibcode: 2014MNRAS.444.2280G.
- ↑ 8.0 8.1 8.2 8.3 8.4 Swastik, C. et al. (March 2021). "Host Star Metallicity of Directly Imaged Wide-orbit Planets: Implications for Planet Formation". The Astronomical Journal 161 (3): 13. doi:10.3847/1538-3881/abd802. 114. Bibcode: 2021AJ....161..114S.
- ↑ 9.0 9.1 9.2 9.3 Miles-Páez, Paulo A. et al. (2017). "The Prototypical Young L/T-Transition Dwarf HD 203030B Likely Has Planetary Mass". The Astronomical Journal 154 (6): 262. doi:10.3847/1538-3881/aa9711. Bibcode: 2017AJ....154..262M.
- ↑ "HD 203030". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+203030.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society 331 (1): 45–59. doi:10.1046/j.1365-8711.2002.05150.x. Bibcode: 2002MNRAS.331...45K.
- ↑ 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. doi:10.1086/507836. Bibcode: 2006ApJ...651.1166M.
Coordinates: 
h 21m 18s, 58.2198+° 26′ 13″
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