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HD 15115
	; Debris disk surrounding young star HD 15115; Credit: NASA, ESA, G. Schneider (University of Arizona), and the HST/GO 12228 Team
Observation data; Epoch J2000 Equinox J2000
Constellation	Cetus
Right ascension	02h 26m 16.24577s
Declination	+06° 17′ 33.1880″
Apparent magnitude (V)	6.76
Characteristics
Spectral type	F4IV or F2V
U−B color index	−0.03
B−V color index	+0.39
Astrometry
Radial velocity (Rv)	0.81±0.12 km/s
Proper motion (μ)	RA: +88.030 mas/yr ; Dec.: -50.515 mas/yr
Parallax (π)	20.4065 ± 0.0418 mas
Distance	159.8 ± 0.3 ly ; (49.0 ± 0.1 pc)
Details
Mass	1.19 M☉
Radius	1.39±0.06 R☉
Luminosity	3.74±0.01 L☉
Surface gravity (log g)	4.30 cgs
Temperature	6,811+148; −152 K
Metallicity [Fe/H]	0.96 dex
Rotational velocity (v sin i)	89.8 km/s
Age	500 Myr
Other designations
	BD+05°338, HD 15115, HIP 11360, SAO 110532, WDS J02263+0618A
Database references
SIMBAD	data

HD 15115 is a single^[10] star in the equatorial constellation of Cetus. It is readily visible in binoculars or a small telescope, but is considered too dim to be seen with the naked eye at an apparent visual magnitude of 6.76.^[2] The distance to this object is 160 light years based on parallax,^[1] and it is slowly drifting further away at the rate of about 1 km/s.^[5] It has been proposed as a member of the Beta Pictoris moving group^[11] or the Tucana-Horologium association of co-moving stars; there is some ambiguity as to its true membership.^[12]

This object has a stellar classification of F4IV,^[3] suggesting it is an aging subgiant star that has exhausted the supply of hydrogen at its core. MacGregor and associates (2015) instead classify it as a young F-type main-sequence star with a class of F2V.^[4] Age estimates give a value of 500^[8] million years, while membership in the β Pictoris moving group would indicate an age of around 21±4 million.^[4] It has 1.19^[6] times the mass of the Sun, 1.39^[1] times the Sun's radius, and has a relatively high rate of spin with a projected rotational velocity of 90 km/s.^[7] The star is radiating 3.74^[1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,811 K.^[1] Its metallicity – the abundance of elements other than hydrogen and helium – is nearly the same as in the Sun.^[6]

HD 15115 was shown to have an asymmetric debris disk surrounding it, which is being viewed nearly edge-on. The reason for the asymmetry is thought to be either the gravitational pull of a passing star (HIP 12545), an exoplanet, or interaction with the local interstellar medium.^[13] A magnitude 11.35 visual companion lies at an angular separation of 12.6″ along a position angle of 195°, as of 2015.^[11]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l 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.
^ ^a ^b ^c ^d Oja, T. (1983). "UBV photometry of FK4 and FK4 supplement stars". Astronomy and Astrophysics Supplement Series. 52: 131. Bibcode:1983A&AS...52..131O.
^ ^a ^b Harlan, E. A. (1974). "MK classification for F- and G-type stars. III". Astronomical Journal. 79: 682. Bibcode:1974AJ.....79..682H. doi:10.1086/111597.
^ ^a ^b ^c MacGregor, Meredith A.; et al. (March 2015). "Resolved Millimeter Emission from the HD 15115 Debris Disk". The Astrophysical Journal. 801 (1): 8. arXiv:1501.05962. Bibcode:2015ApJ...801...59M. doi:10.1088/0004-637X/801/1/59. S2CID 118407532. 59.
^ ^a ^b Desidera, S.; et al. (January 2015). "The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits. I. Sample definition and characterization". Astronomy & Astrophysics. 573: 45. arXiv:1405.1559. Bibcode:2015A&A...573A.126D. doi:10.1051/0004-6361/201323168. S2CID 55486025. A126.
^ ^a ^b ^c ^d ^e Luck, R. Earle (March 2018), "Abundances in the Local Region. III. Southern F, G, and K Dwarfs", The Astronomical Journal, 155 (3): 31, Bibcode:2018AJ....155..111L, doi:10.3847/1538-3881/aaa9b5, S2CID 125765376, 111.
^ ^a ^b Pribulla, Theodor; et al. (September 2014). "Cerro Armazones spectroscopic survey of F dwarfs". Monthly Notices of the Royal Astronomical Society. 443 (3): 2815–2823. Bibcode:2014MNRAS.443.2815P. doi:10.1093/mnras/stu1333.
^ ^a ^b Decin, G.; et al. (November 2003), "Age Dependence of the Vega Phenomenon: Observations", The Astrophysical Journal, 598 (1): 636–644, arXiv:astro-ph/0308294, Bibcode:2003ApJ...598..636D, doi:10.1086/378800, S2CID 16751327
^ "HD 15115". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-15.
^ Rodriguez, David R.; Zuckerman, B. (February 2012). "Binaries among Debris Disk Stars". The Astrophysical Journal. 745 (2): 13. arXiv:1111.5618. Bibcode:2012ApJ...745..147R. doi:10.1088/0004-637X/745/2/147. S2CID 73681879. 147.
^ ^a ^b Alonso-Floriano, F. J.; et al. (November 2015). "Reaching the boundary between stellar kinematic groups and very wide binaries. III. Sixteen new stars and eight new wide systems in the β Pictoris moving group". Astronomy & Astrophysics. 583: 24. arXiv:1508.06929. Bibcode:2015A&A...583A..85A. doi:10.1051/0004-6361/201526795. S2CID 3131908. A85.
^ Malo, Lison; et al. (January 2013), "Bayesian Analysis to Identify New Star Candidates in Nearby Young Stellar Kinematic Groups", The Astrophysical Journal, 762 (2): 50, arXiv:1209.2077, Bibcode:2013ApJ...762...88M, doi:10.1088/0004-637X/762/2/88, S2CID 118497872, 88.
^ Debes, J. H.; et al. (2009). "Interstellar Medium Sculpting of the Hd 32297 Debris Disk". The Astrophysical Journal. 702 (1): 318–326. arXiv:0908.4368. Bibcode:2009ApJ...702..318D. doi:10.1088/0004-637X/702/1/318. S2CID 15303091.