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HD 203949 - Wikipedia

Coordinates:

21^h 26^m 22.8745^s, −37° 49′ 45.9539″

From Wikipedia, the free encyclopedia

(Redirected from HD 203949 b)

HD 203949
Observation data Epoch J2000 Equinox J2000
Location of HD 203949 on the map (circled)
Constellation	Microscopium
Right ascension	21^h 26^m 22.8745^s^[1]
Declination	−37° 49′ 45.950″^[1]
Apparent magnitude (V)	5.62±0.01^[2]
Characteristics
Evolutionary stage	giant
Spectral type	K2III^[3]
Astrometry

Radial velocity (R_v)	−83.50±0.16^[1] km/s
Proper motion (μ)	RA: 168.257^[1] mas/yr Dec.: −11.075^[1] mas/yr
Parallax (π)	12.6806 ± 0.0577 mas^[1]
Distance	257 ± 1 ly (78.9 ± 0.4 pc)
Absolute magnitude (M_V)	+1.10^[4]

Details^[2]

Mass	1.00±0.16 `M`_☉
Radius	10.30±0.51 `R`_☉
Luminosity (bolometric)	43.34±4.27 `L`_☉
Surface gravity (log g)	2.415±0.044 cgs
Temperature	4618±113 K
Metallicity [Fe/H]	0.17±0.07 dex
Age	7.29±3.06 Gyr

Other designations
CD−38 14551, Gaia DR2 6583094222249556224, HIP 105854, HR 8200, TYC 7979-47-1, GSC 07979-00047, 2MASS J21262286-3749458^[5]
Database references
SIMBAD	data

HD 203949 is a K-type giant star 257 light-years away in the constellation of Microscopium. Its surface temperature is 4618±113 K. It is either on the red giant branch fusing hydrogen in a shell around a helium core, or more likely a red clump star currently fusing helium in its core.^[2] HD 203949 is enriched in heavy elements relative to the Sun, with a metallicity ([Fe/H]) of 0.17±0.07 dex. As is common for red giants, HD 203949 has an enhanced concentration of sodium and aluminium compared to iron.^[2]

Multiplicity surveys did not find any stellar companions around HD 203949 as of 2019.^[6]

Planetary system

In 2014, one planet orbiting HD 203949 was discovered by the radial velocity method.^[7] The planet is highly unlikely to have survived the red giant stage of stellar evolution on the present orbit. It is likely to be recently scattered from a wider orbit.^[2]

The planetary system configuration is favourable for direct imaging of exoplanets in the near future, and was included in the top ten easiest targets known by 2018.^[8]

The HD 203949 planetary system^[7]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
HIP 105854b	>8.2±0.2^{[note 1]} $M$ _J	0.81±0.03	184.2±0.5	0.02±0.03	—	—

^ Planetary minimal mass must be revised down by 30% according to Campante et al.^[2]

References

^ ^a ^b ^c ^d ^e ^f Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
^ ^a ^b ^c ^d ^e ^f Campante, Tiago L.; et al. (2019). "TESS Asteroseismology of the Known Red-giant Host Stars HD 212771 and HD 203949". The Astrophysical Journal. 885 (1): 31. arXiv:1909.05961. Bibcode:2019ApJ...885...31C. doi:10.3847/1538-4357/ab44a8. S2CID 202572968.
^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
^ 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.
^ "HD 121056". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-05-13.
^ Biller, B.; Mužić, K.; Lopez, E.; Bonavita, M.; Rice, K.; Fontanive, C. (2019). "A high binary fraction for the most massive close-in giant planets and brown dwarf desert members". Monthly Notices of the Royal Astronomical Society. 485 (4): 4967–4996. arXiv:1903.02332. doi:10.1093/mnras/stz671.
^ ^a ^b Jones, M. I.; Jenkins, J. S.; Bluhm, P.; Rojo, P.; Melo, C. H. F. (2014). "The properties of planets around giant stars". Astronomy & Astrophysics. 566: A113. arXiv:1406.0884. Bibcode:2014A&A...566A.113J. doi:10.1051/0004-6361/201323345. S2CID 118396750.
^ Martinache, Frantz; Ireland, Michael J. (2018). "Kernel-nulling for a robust direct interferometric detection of extrasolar planets". Astronomy & Astrophysics. 619: A87. arXiv:1802.06252. Bibcode:2018A&A...619A..87M. doi:10.1051/0004-6361/201832847. S2CID 118882482.

Constellation of Microscopium

Stars

Bayer	α β γ δ ε ζ η θ¹ θ² ι ν
Flamsteed	2 PsA 3 PsA
Variable	R S T U AT AU AV AX BO DD
HR	7817 7893 7909 7933 7971 7987 8046 8100 8104 8108 8200 8202
HD	202628
Other	PSR J2124−3358 WASP-7

Exoplanets	WASP-7b

Galaxies

NGC	6925 7012 7057 7060
Other	ESO 286-19