HD 99109

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HD 99109 / Shama
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Leo
Right ascension 11h 24m 17.359s [1]
Declination –01° 31′ 44.67″ [1]
Apparent magnitude  (V)+9.10 [2]
Characteristics
Spectral type G8/K0IV [3]
B−V color index 0.874±0.002 [2]
Astrometry
Radial velocity (Rv)+33.060±0.0025 [4] km/s
Proper motion (μ)RA: −178.689 mas/yr [1]
Dec.: −159.528 mas/yr [1]
Parallax (π)18.178±0.017  mas [1]
Distance 179.4 ± 0.2  ly
(55.01 ± 0.05  pc)
Absolute magnitude  (MV)5.62 [2]
Details
Mass 0.93±0.02 [5]   M☉
Radius 0.90±0.03 [5]   R☉
Luminosity 0.56±0.02 [5]   L☉
Surface gravity (log g)4.49±0.03 [5]   cgs
Temperature 5,270±24 [5]   K
Metallicity [Fe/H]0.315±0.030 [6]   dex
Rotational velocity (v sin i)1.86±0.50 [6]  km/s
Age 6±3 Gyr [5]
≥ 12.2 [7]   Gyr
Other designations
Shama, BD−00°2437, HD 99109, HIP 55664, SAO 138182 [8]
Database references
SIMBAD data
Exoplanet Archive data

HD 99109 is an orange-hued star with an exoplanetary companion in the constellation of Leo. It has an absolute visual magnitude of +9.10, [2] which is too faint to be visible to the naked eye. The distance to this system is 179  light-years based on parallax, and it is drifting further away with a radial velocity of +33 km/s. [1] The star is one and half degrees away from the celestial equator to the south.

The stellar classification of this star is G8/K0IV, [3] matching a late G or early K-type subgiant star. It appears to be past the end of its main sequence lifetime, having exhausted the supply of hydrogen at its core. [7] The star is 93% as massive as the Sun and has 90% of the Sun's radius. [5] It is spinning with a projected rotational velocity of ~2 km/s [6] and has over twice the abundance of iron relative to hydrogen than the Sun. The star is radiating 56% of the Sun's luminosity from its photosphere at an effective temperature of 5,270 K. [5] As of 2006, one extrasolar planet has been confirmed to be orbiting the star. [6]

The star HD 99109 is named Shama. The name was selected in the NameExoWorlds campaign by Pakistan, during the 100th anniversary of the IAU. Shama ( شمع ) is an Urdu literary term meaning a small lamp or flame. The exoplanet companion is called Perwana, meaning 'moth' in Urdu, alluding to the eternal love of an object circling a source of light. [9] [10]

Planetary system

The planet HD 99109 b has an orbit comparable in eccentricity to the planet Mars in the Solar System but has a mass at least half that of Jupiter. Stability analysis reveals that Earth-size planets could have stable orbits in the planet's Trojan points, located 60 degrees ahead and behind the planet's position in its orbit. [7]

The HD 99109 planetary system [6]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Perwana >0.502 ± 0.070  MJ 1.105 ± 0.065439.3 ± 5.60.09 ± 0.16——

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 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. 1 2 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. ↑ Soubiran, C.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv: 1804.09370 . Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795. S2CID   52952408.
  5. 1 2 3 4 5 6 7 8 Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv: 1511.01744 . Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID   53971692. A5.
  6. 1 2 3 4 5 Butler, R. P.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv: astro-ph/0607493 . Bibcode:2006ApJ...646..505B. doi:10.1086/504701. S2CID   119067572.
  7. 1 2 3 Schwarz, R.; et al. (November 2007). "Survey of the stability region of hypothetical habitable Trojan planets". Astronomy & Astrophysics. 474 (3): 1023–1029. Bibcode:2007A&A...474.1023S. doi: 10.1051/0004-6361:20077994 .: HD 93083, HD 17051, HD 28185, HD 27442, HD 188015, HD 99109, HD 221287
  8. ↑ "HD 99109". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2015-12-21.
  9. ↑ "Approved names". NameExoworlds. IAU. Retrieved 2020-01-02.
  10. ↑ "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
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