HD 190228

From Wikipedia, the free encyclopedia
HD 190228
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Vulpecula
Right ascension 20h 03m 00.7728s[1]
Declination +28° 18′ 24.6849″[1]
Apparent magnitude (V) 7.30[2]
Characteristics
Spectral type G5IV[3]
B−V color index 0.793±0.006[2]
Astrometry
Radial velocity (Rv)−50.70±0.59[2] km/s
Proper motion (μ) RA: 104.146±0.046[1] mas/yr
Dec.: −69.806±0.043[1] mas/yr
Parallax (π)15.9164 ± 0.0305[1] mas
Distance204.9 ± 0.4 ly
(62.8 ± 0.1 pc)
Absolute magnitude (MV)3.36[2]
Orbit[4]
Period (P)1,146.0±16.0 d
Eccentricity (e)0.50±0.04
Inclination (i)4.3+1.8
−1.0°
Longitude of the node (Ω)61.0+22.7
−22.9°
Argument of periastron (ω)
(primary)		100.7±3.2°
Details
HD 190228
Mass0.83 M☉[5]
1.19[6] M☉
Surface gravity (log g)4.02±10[5] cgs
Temperature5,360±40[5] K
Metallicity [Fe/H]–0.24±0.06[5] dex
Rotational velocity (v sin i)4.4[6] km/s
Age5.1[6] Gyr
HD 190228 b
Mass0.0472±0.0141[4] M☉
Other designations
BD+27° 3593, HD 190228, HIP 98714, SAO 88118, GCRV 70273[7]
Database references
SIMBADdata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

HD 190228 is a star with a non-stellar companion in the constellation Vulpecula. Its apparent magnitude is 7.30 – too faint to be seen with the naked eye – and the absolute magnitude is 3.34. Based on parallax measurements, it is located at a distance of 205 light years from the Sun. The star is older than the Sun with an age over 5 billion years and it is metal-poor.[5]

In 2000, it was announced that a giant planet was orbiting the star with a minimum mass of 5 Jupiter masses, designated HD 190228 b.[8] The planetary nature of the object was questioned because of the low metal content of the star: giant planets are more likely to be found around high-metallicity stars, so it was argued that the object was more likely to be a brown dwarf.[9] Later astrometric measurements confirmed this: HD 190228 b is in fact a brown dwarf of 49.4 Jupiter masses in a nearly face-on orbit. The brown dwarf takes 1146 days to orbit the star, and the orbit is elliptical with an eccentricity of 0.5.[4]

References[]

  1. ^ a b c d 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. ^ a b c d 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. ^ White, Russel J.; et al. (June 2007). "High-Dispersion Optical Spectra of Nearby Stars Younger Than the Sun". The Astronomical Journal. 133 (6): 2524–2536. arXiv:0706.0542. Bibcode:2007AJ....133.2524W. doi:10.1086/514336. S2CID 122854.
  4. ^ a b c Sahlmann, J.; et al. (2011). "The companion of HD 190228: Planet or brown dwarf?". Astronomy and Astrophysics. 525. A95. arXiv:1009.5991. Bibcode:2011A&A...525A..95S. doi:10.1051/0004-6361/201015427. S2CID 119276951.
  5. ^ a b c d e Perrier, C.; et al. (2003). "The ELODIE survey for northern extra-solar planets. I. Six new extra-solar planet candidates". Astronomy and Astrophysics. 410 (3): 1039–1049. arXiv:astro-ph/0308281. Bibcode:2003A&A...410.1039P. doi:10.1051/0004-6361:20031340. S2CID 6946291.
  6. ^ a b c Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 19. arXiv:1611.02897. Bibcode:2017AJ....153...21L. doi:10.3847/1538-3881/153/1/21. S2CID 119511744. 21.
  7. ^ "HD 190228". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-01-25.
  8. ^ "European Southern Observatory: Six Extrasolar Planets Discovered". SpaceRef Interactive Inc. 7 August 2000. Retrieved 15 August 2009.
  9. ^ Chen, Y. Q.; Zhao, G. (2001). "The companion of HD 190228: Planet or brown dwarf?". Astronomy and Astrophysics. 374 (1): L1–L4. Bibcode:2001A&A...374L...1C. doi:10.1051/0004-6361:20010790.


Stub icon

This subgiant-star-related article is a stub. You can help Wikipedia by .

  • v
  • t
Retrieved from ""