HD 102272

HD 102272 is a star in the equatorial constellation of Leo. With an apparent visual magnitude of 8.69,^[2] it is too faint to be visible to the naked eye. The star is located at a distance of approximately 1,140 light years based on parallax measurements, but is drifting closer to the Sun with a radial velocity of −12 km/s.^[2] As of 2008^[update], two extrasolar planets are known to orbit the star.^[5]

HD 102272

Observation data Epoch J2000.0 (ICRS)      Equinox J2000.0 (ICRS)
Constellation	Leo
Right ascension	11h 46m 23.535s[1]
Declination	+14° 07′ 26.35″[1]
Apparent magnitude (V)	8.69[2]
Characteristics
Spectral type	K0[3] III[2]
U−B color index	0.69[3]
B−V color index	1.02[2]
Astrometry
Radial velocity (Rv)	−11.99±0.03[2] km/s
Proper motion (μ)	RA: −7.371[1] mas/yr Dec.: 7.639[1] mas/yr
Parallax (π)	2.8571 ± 0.1135 mas[1]
Distance	1,140 ± 50 ly (350 ± 10 pc)
Absolute magnitude (MV)	0.74[2]
Details[2]
Mass	1.01±0.122 M☉
Radius	8.02±2.14 R☉
Luminosity	25 L☉
Surface gravity (log g)	2.57±0.04 cgs
Temperature	4,750±10 K
Metallicity [Fe/H]	−0.49±0.06 dex
Rotational velocity (v sin i)	2.10±0.90 km/s
Age	8.13 Gyr
Other designations
BD+14 2434, HD 102272, HIP 57428, SAO 99784[4]
Database references
SIMBAD	data

This is an evolved giant star^[2] with a stellar classification of K0.^[3] It is an estimated eight billion years old and has expanded to eight times the Sun's radius. The star has about the same mass as the Sun and is spinning with a projected rotational velocity of 2 km/s. It is radiating 25 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,750 K.^[2]

Planetary system

In June 2008, the discovery of two extrasolar planets orbiting the star was announced.^[5] The planets were detected using the radial velocity method with the Hobby-Eberly Telescope. The radial velocity data clearly shows the presence of the inner planet (HD 102272 b). Although there is evidence for another planet, there is insufficient data to unambiguously determine its orbit.^[3] The pair are close to a 4:1 orbital resonance with the outer planet in a high eccentricity orbit.^[6]

The HD 102272 planetary system^[3]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	>5.9 ± 0.2 MJ	0.614 ± 0.001	127.58 ± 0.30	0.05 ± 0.04	—	—
c	>2.6 ± 0.4 MJ	1.57 ± 0.05	520 ± 26	0.68 ± 0.06	—	—

See also

• List of stars in Leo

References

1. 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.
2. Deka-Szymankiewicz, B.; et al. (2018). "The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample". Astronomy and Astrophysics. 615: A31. arXiv:1801.02899. Bibcode:2018A&A...615A..31D. doi:10.1051/0004-6361/201731696. S2CID 85526201.
3. Niedzielski, A.; et al. (2009). "A Planet in a 0.6 AU Orbit Around the K0 Giant HD 102272". The Astrophysical Journal. 693 (1): 276–280. arXiv:0810.1710. Bibcode:2009ApJ...693..276N. doi:10.1088/0004-637X/693/1/276. S2CID 16074041.
4. "HD 102272". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-01-17.
5. "Notes for star HD 102272". Extrasolar Planets Encyclopaedia. Archived from the original on July 25, 2008. Retrieved 2008-07-01.
6. Antoniadou, Kyriaki I.; Voyatzis, George (October 2016). "Orbital stability of coplanar two-planet exosystems with high eccentricities". Monthly Notices of the Royal Astronomical Society. 461 (4): 3822–3834. arXiv:1606.07743. Bibcode:2016MNRAS.461.3822A. doi:10.1093/mnras/stw1553.

External links

• "Notes for star HD 102272". Extrasolar Planets Encyclopaedia. Archived from the original on July 25, 2008. Retrieved 2008-07-01.
• "HD 102272". Exoplanets. Archived from the original on 2009-11-24. Retrieved 2008-11-09.