HD 215152

HD 215152
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquarius
Right ascension 22h 43m 21.30188s[1]
Declination −06° 24′ 02.96″[1]
Apparent magnitude (V) 8.13[2]
Characteristics
Spectral type K3 V[3]
B−V color index 0.968[4]
Astrometry
Radial velocity (Rv)−13.80[5] km/s
Proper motion (μ) RA: −30.50[1] mas/yr
Dec.: −6.10[1] mas/yr
Parallax (π)46.47 ± 0.90[1] mas
Distance70 ± 1 ly
(21.5 ± 0.4 pc)
Details
Mass0.756±0.016[6] M☉
Surface gravity (log g)4.26±0.15[6] cgs
Temperature4,803±52[6] K
Metallicity [Fe/H]−0.08±0.02[6] dex
Rotational velocity (v sin i)3.35[4] km/s
Age5.207±4.069[6] Gyr
Other designations
BD−07° 5839, GJ 4291, HD 215152, HIP 112190, SAO 146275.[7]

HD 215152 is the Henry Draper Catalogue designation for a star in the zodiac constellation of Aquarius. It has an apparent visual magnitude of 8.13,[2] meaning it is too faint to be seen with the naked eye. Parallax measurements made by the Hipparcos spacecraft provide a distance estimate of around 70 light years.[1] The star has a relatively high proper motion,[7] moving across the sky at an estimated 0.328 arc seconds per year along a position angle of 205°.[8]

This star has a stellar classification of K3 V,[3] which indicates that it is an ordinary K-type main sequence star. Based upon observation of regular variations in chromospheric activity, it has a rotation period of 36.5±1.6 days.[9] Stellar models give an estimated mass of around 76% of the Sun.[6] It has a slightly lower metallicity than the Sun,[6] and thus has a lower abundance of elements other than hydrogen and helium. The effective temperature of the stellar atmosphere is about 4,803 K, giving it the orange-hued glow of an ordinary K-type star.[10]

HD 215152 is a candidate for possessing a debris disk—a circumstellar disk of orbiting dust and debris. This finding was made through the detection of an infrared excess at a wavelength of 70 μm by the Spitzer Space Telescope. The detection has a 3σ level of certainty.[11]

In 2011, it was reported that two planetary candidates had been detected in close orbit around this star. The planets were discovered through Doppler spectroscopy using the HARPS spectrograph at La Silla Observatory in Chile. Their presence was revealed by periodic variations in the radial velocity of the host star due to gravitational perturbations by the orbiting objects. Both planets have brief orbital periods: the inner planet is orbiting the host star every 7.28 days while the outer planet orbits every 10.86 days. Their individual masses are more than twice that of the Earth, placing them in the regime of Super-Earth or Neptune mass planets.[12]

The HD 215152 planetary system[12]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥ 2.78±0.47 M⊕ 0.0652±0.0010 7.283±0.006 0.34±0.27 — —
c ≥ 3.10±0.48 M⊕ 0.0852±0.0014 10.866±0.014 0.38±0.23 — —

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 Santos, N. C.; et al. (2013), "SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs", Astronomy and Astrophysics 556, A150, arXiv:1307.0354, Bibcode:2013A&A...556A.150S, doi:10.1051/0004-6361/201321286.
  3. 1 2 Gray, R. O.; et al. (2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I", The Astronomical Journal 126 (4): 2048–2059, arXiv:astro-ph/0308182, Bibcode:2003AJ....126.2048G, doi:10.1086/378365.
  4. 1 2 Martínez-Arnáiz, R.; et al. (September 2010), "Chromospheric activity and rotation of FGK stars in the solar vicinity. An estimation of the radial velocity jitter", Astronomy and Astrophysics 520: A79, arXiv:1002.4391, Bibcode:2010A&A...520A..79M, doi:10.1051/0004-6361/200913725.
  5. ↑ Latham, David W.; et al. (August 2002), "A Survey of Proper-Motion Stars. XVI. Orbital Solutions for 171 Single-lined Spectroscopic Binaries", The Astronomical Journal 124 (2): 1144−1161, Bibcode:2002AJ....124.1144L, doi:10.1086/341384.
  6. 1 2 3 4 5 6 7 Tsantaki, M.; et al. (July 2013), "Deriving precise parameters for cool solar-type stars. Optimizing the iron line list", Astronomy & Astrophysics 555: A150, arXiv:1304.6639, Bibcode:2013A&A...555A.150T, doi:10.1051/0004-6361/201321103.
  7. 1 2 "HD 215152 -- High proper-motion Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved March 14, 2016
  8. ↑ Carney, Bruce W.; et al. (June 1994), "A survey of proper motion stars. XII. An expanded sample", The Astronomical Journal 107 (6): 2240−2289, Bibcode:1994AJ....107.2240C, doi:10.1086/117035.
  9. ↑ Suárez Mascareño, A.; et al. (September 2015), "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators", Monthly Notices of the Royal Astronomical Society 452 (3): 2745−2756, arXiv:1506.08039, Bibcode:2015MNRAS.452.2745S, doi:10.1093/mnras/stv1441.
  10. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16.
  11. ↑ Koerner, D. W.; et al. (February 2010), "New Debris Disk Candidates Around 49 Nearby Stars", The Astrophysical Journal Letters 710 (1): L26−L29, Bibcode:2010ApJ...710L..26K, doi:10.1088/2041-8205/710/1/L26.
  12. 1 2 Mayor, M.; et al. (September 2011), The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets, arXiv:1109.2497, Bibcode:2011arXiv1109.2497M.
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