HD 153950

HD 153950 is a star in the southern constellation of Scorpius, positioned about 1.2° to the west of Eta Scorpii.[8] It has the proper name Rapeto, which was selected in the NameExoWorlds campaign by Madagascar, during the 100th anniversary of the IAU. Rapeto is a giant creature from Malagasy tales.[9][10] This star is visible in a small telescope, having an apparent visual magnitude of 7.39.[2] It is located at a distance of 158 light years from the Sun based on parallax. The star is drifting further away with a radial velocity of 33.2 km/s.[2]

HD 153950 / Rapeto
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 17h 04m 30.87092s[1]
Declination −43° 18′ 35.1705″[1]
Apparent magnitude (V) 7.39[2]
Characteristics
Spectral type F8V[3]
Apparent magnitude (B) 7.955[2]
Apparent magnitude (J) 6.313±0.018[2]
Apparent magnitude (H) 6.078±0.034[2]
Apparent magnitude (K) 6.006±0.017[2]
B−V color index 0.565±0.011[2]
Astrometry
Radial velocity (Rv)33.23±0.01[2] km/s
Proper motion (μ) RA: +110.494[1] mas/yr
Dec.: −140.694[1] mas/yr
Parallax (π)20.6090 ± 0.0493 mas[1]
Distance158.3 ± 0.4 ly
(48.5 ± 0.1 pc)
Absolute magnitude (MV)3.91[4]
Details[4]
Mass1.119±0.027[5] M☉
Radius1.28±0.04[6] R☉
Luminosity2.22±0.17 L☉
Surface gravity (log g)4.37±0.1 cgs
Temperature6,076±13 K
Metallicity [Fe/H]−0.01±0.01 dex
Rotation14 days
Rotational velocity (v sin i)3.0 km/s
Age4.676±0.932[5] Gyr
Other designations
Rapeto, CD–43°11380, HIP 83547, SAO 227597, PPM 322565, LTT 6814, GSC 07881-00474, 2MASS J17043086-4318351[7]
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data

The stellar classification of F8V[3] suggests HD 153950 is an F-type main-sequence star. However, given its position on the H-R diagram, this star has likely already started to evolve off the main sequence.[11] It is about 4.7[5] billion years old and is spinning with a projected rotational velocity of 3.0 km/s, giving it a rotation period of ~14 days.[4] The star has 12%[5] more mass than the Sun and a 28%[6] greater radius. The abundance of iron, what astronomers term the star's metallicity, is equal to the Sun within the margin of error. It is radiating more than double the luminosity of the Sun from its photosphere at an effective temperature of 6,076 K.[4]

Planetary system

In October 2008, an exoplanet of this star was discovered. This object was detected using the radial velocity method by search programs conducted using the HARPS spectrograph. It is a super-Jupiter with an eccentric orbit that has a period of 1.37 years.[4] Although the semimajor axis of 1.28 AU lies near the inner edge of the extended habitable zone, about half the orbit lies within the moist greenhouse limit. At periapsis, the exoplanet comes as close as 0.84 AU to its parent star.[11]

The HD 153950 planetary system[4]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Trimobe ≥2.73±0.05 MJ 1.28±0.01 499.4±3.6 0.34±0.021 — —

See also

References
  1. 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. 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. Houk, N. (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 2. Dept. of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
  4. Moutou, C.; et al. (2009). "The HARPS search for southern extra-solar planets XVII. Six long-period giant planets around BD -17 0063, HD 20868, HD 73267, HD 131664, HD 145377, HD 153950". Astronomy and Astrophysics. 496 (2): 513–519. arXiv:0810.4662. Bibcode:2009A&A...496..513M. doi:10.1051/0004-6361:200810941. S2CID 116707055.
  5. Delgado Mena, E.; et al. (April 2019). "Abundance to age ratios in the HARPS-GTO sample with Gaia DR2. Chemical clocks for a range of [Fe/H]". Astronomy & Astrophysics. 624: 24. arXiv:1902.02127. Bibcode:2019A&A...624A..78D. doi:10.1051/0004-6361/201834783. S2CID 90259810. A78.
  6. Stassun, Keivan G.; et al. (March 2017). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal. 153 (3): 20. arXiv:1609.04389. Bibcode:2017AJ....153..136S. doi:10.3847/1538-3881/aa5df3. S2CID 119219062. 136.
  7. "HD 153950". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-12-04.
  8. Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 3. Sky Publishing Corporation and the European Space Agency. p. 1460. ISBN 0-933346-84-0.
  9. "Approved names". NameExoworlds. Retrieved 2020-01-02.
  10. "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  11. Sato, S.; et al. (May 2017). "Climatological and ultraviolet-based habitability of possible exomoons in F-star systems". Astronomische Nachrichten. 338 (4): 413–427. arXiv:1503.02560. Bibcode:2017AN....338..413S. doi:10.1002/asna.201613279. S2CID 118668172.
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