Astronomy:HD 99109
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas/yr Dec.: −159.528[1] mas/yr |
| Parallax (π) | 18.178 ± 0.017[1] mas |
| 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 | |
| Database references | |
| SIMBAD | data |
| Extrasolar Planets Encyclopaedia | 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 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]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Perwana | >0.502 ± 0.070 MJ | 1.105 ± 0.065 | 439.3 ± 5.6 | 0.09 ± 0.16 | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 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 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey 5. Bibcode: 1999MSS...C05....0H.
- ↑ Soubiran, C. et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics 616: A7. doi:10.1051/0004-6361/201832795. Bibcode: 2018A&A...616A...7S.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics 585: 14. doi:10.1051/0004-6361/201527297. A5. Bibcode: 2016A&A...585A...5B.
- ↑ 6.0 6.1 6.2 6.3 6.4 Butler, R. P. et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. doi:10.1086/504701. Bibcode: 2006ApJ...646..505B.
- ↑ 7.0 7.1 7.2 Schwarz, R. et al. (November 2007). "Survey of the stability region of hypothetical habitable Trojan planets". Astronomy & Astrophysics 474 (3): 1023–1029. doi:10.1051/0004-6361:20077994. Bibcode: 2007A&A...474.1023S. https://uscholar.univie.ac.at/detail/o:245382.download.: HD 93083, HD 17051, HD 28185, HD 27442, HD 188015, HD 99109, HD 221287
- ↑ "HD 99109". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+99109.
- ↑ "Approved names" (in en). IAU. http://www.nameexoworlds.iau.org/final-results.
- ↑ "International Astronomical Union | IAU". https://www.iau.org/news/pressreleases/detail/iau1912/.
Coordinates: 
11h 24m 17.358s, −01° 31′ 44.674″
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