HIP 70849

HIP 70849 is a star with one or more non-stellar companions in the southern constellation Lupus. It is a 10th magnitude star, making it too faint to be visible to the naked eye.[2] The system is located at a distance of 78.5 light-years from the Sun based on parallax measurements.[1]

HIP 70849
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lupus
Right ascension 14h 29m 18.564s[1]
Declination −46° 27′ 49.74″[1]
Apparent magnitude (V) 10.36[2]
Characteristics
Spectral type K7Vk[3]
Apparent magnitude (B) 11.787[2]
Apparent magnitude (J) 7.639±0.023[2]
Apparent magnitude (H) 7.006±0.061[2]
Apparent magnitude (K) 6.790±0.027[2]
B−V color index 1.427±0.019[2]
Variable type 8.50[2]
Astrometry
Radial velocity (Rv)−0.134±0.0013[4] km/s
Proper motion (μ) RA: −43.981 mas/yr[1]
Dec.: −201.760 mas/yr[1]
Parallax (π)41.5387 ± 0.0424 mas[1]
Distance78.52 ± 0.08 ly
(24.07 ± 0.02 pc)
Absolute magnitude (MV)8.5[2]
Details
Mass0.63±0.03[5]
0.76±0.07[6] M☉
Radius0.62±0.02[5] R☉
Luminosity (bolometric)0.0892±0.0005[5] L☉
Surface gravity (log g)3.70±0.09[6] cgs
Temperature4,103±25[6] K
Metallicity [Fe/H]0.00±0.03[6] dex
Rotation41.2 d[5]
Rotational velocity (v sin i)1.93 km/s[5]
0.30±0.30[6] km/s
Age3.6±0.15[5] Gyr
Other designations
NSV 6678, CD−45°9206, GJ 550.3, HIP 70849, PPM 760399, LTT 5717, NLTT 37446[7]
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data

This is a K-type main-sequence star with a stellar classification of K7Vk,[3] where the 'k' indicates interstellar absorption features in the spectrum. The star is magnetically active with a 10.1±1.4 yr starspot cycle. It appears about 3.6 billion years old and the light emission shows a 41.2 day periodicity, which is likely the rotation period.[5] This star, which resembles a brighter red dwarf, is smaller and less massive than our Sun. It is radiating just 9%[5] of the luminosity of the Sun from its photosphere at an effective temperature of 4,103 K.[6]

In 2009, a gas giant planet/brown dwarf was found in orbit around it. Designated HIP 70849 b it has more than five times the mass of Jupiter and takes more than 3000 days to orbit at a semimajor axis of more than 3.5 AU.[8] There is also a potential T4.5 brown dwarf companion orbiting ~9000AU from HIP 70849.[9]

The HIP 70849 planetary system[8]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b >5 MJ >3.5 >3000  ? — —

See also

References
  1. 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.
  2. 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. Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  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. Zurlo, A.; et al. (October 2018). "Imaging radial velocity planets with SPHERE". Monthly Notices of the Royal Astronomical Society. 480 (1): 35–48. arXiv:1807.01324. Bibcode:2018MNRAS.480...35Z. doi:10.1093/mnras/sty1809.
  6. Sousa, S. G.; et al. (November 2018). "SWEET-Cat updated. New homogenous spectroscopic parameters". Astronomy & Astrophysics. 620: 13. arXiv:1810.08108. Bibcode:2018A&A...620A..58S. doi:10.1051/0004-6361/201833350. S2CID 119374557. A58.
  7. "CD-45 9206". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-11-11.
  8. Ségransan, D.; et al. (2011). "The HARPS search for southern extra-solar planets. XXIX. Four new planets in orbit around the moderately active dwarfs HD 63765, HD 104067, HD 125595, and HIP 70849". Astronomy and Astrophysics. 535. A54. arXiv:1107.0339. Bibcode:2011A&A...535A..54S. doi:10.1051/0004-6361/200913580. S2CID 119197766.
  9. Lodieu, N.; et al. (2014). "Binary frequency of planet-host stars at wide separations. A new brown dwarf companion to a planet-host star". Astronomy and Astrophysics. 569. A120. arXiv:1408.1208. Bibcode:2014A&A...569A.120L. doi:10.1051/0004-6361/201424210. S2CID 118516214.

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