HD 7199

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HD 7199 / Emiw
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Tucana
Right ascension 01h 10m 47.22139s[1]
Declination −66° 11′ 17.3901″[1]
Apparent magnitude (V) +8.06[2]
Spectral type K1IV[3]
B−V color index 0.849±0.012[2]
Radial velocity (Rv)+5.63±0.15[2] km/s
Proper motion (μ) RA: +110.513[1] mas/yr
Dec.: −123.283[1] mas/yr
Parallax (π)27.6312 ± 0.0276 mas[1]
Distance118.0 ± 0.1 ly
(36.19 ± 0.04 pc)
Absolute magnitude (MV)5.32[2]
Mass0.93±0.02 M
Radius0.98±0.02 R
Luminosity0.70±0.01 L
Surface gravity (log g)4.42±0.03 cgs
Temperature5,349±38 K
Metallicity [Fe/H]+0.39±0.106[5] dex
Rotation42.89±4.66[6] d
Rotational velocity (v sin i)2.209±0.327[5] km/s
Age9.5±2.4 Gyr
Other designations
Emiw, CD−66°60, Gaia DR2 4704957491028733824, HD 7199, HIP 5529, SAO 248334, 2MASS J01104719-6611171[7]
Database references
Exoplanet Archivedata

HD 7199 is a star in the constellation Tucana located 118 light years distance from the Sun based on parallax. It has an orange hue but is too dim to be viewed with the naked eye, having an apparent visual magnitude of +8.06.[2] The star is drifting further away from the Sun with a radial velocity of +5.6 km/s.[2]

The star HD 7199 is named Emiw. The name was selected in the NameExoWorlds campaign by Mozambique, during the 100th anniversary of the IAU. Emiw represents love in the local Makhuwa language.[8][9]

This object has a stellar classification of K1IV,[3] matching a K-type subgiant star that is in the process of cooling and expanding off the main sequence, having exhausted the supply of hydrogen at its core. It is around 10[4] billion years old with a low projected rotational velocity of 2.2 km/s.[5] The star looks to be very metal-rich, having more than double the abundance of iron compared to the Sun.[5] Both mass and radius are lower than the Sun's, and it only radiates 70% of the Sun's luminosity.[4] It displays a Sun-like magnetic activity cycle.[6]

Planetary system[edit]

The High Accuracy Radial Velocity Planet Searcher (HARPS) in Chile found it to have a planet with a minimum of 0.29 times the mass of Jupiter – 92 times the mass of Earth – with an orbital period of 615 days.[6]

The planet HD 7199 b was named Hairu in 2019. Hairu represents unity in the Makhuwa language.[8][9]

The HD 7199 planetary system[10]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
HD 7199 b (Hairu) >0.29±0.023 MJ 1.36±0.02 615±7 0.36±0.12


  1. ^ a b c d e 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. ^ a b c d e f 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. ^ a b Gray, R. O.; et al. (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. ^ a b c Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
  5. ^ a b c d Soto, M. G.; Jenkins, J. S. (July 2018). "Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars (SPECIES). I. Code description and dwarf stars catalogue". Astronomy & Astrophysics. 615: 28. arXiv:1801.09698. Bibcode:2018A&A...615A..76S. doi:10.1051/0004-6361/201731533. S2CID 119107228. A76.
  6. ^ a b c Dumusque, X.; et al. (November 2011). "The HARPS Search for Southern Extra-solar Planets. XXX. Planetary Systems around Stars with Solar-like Magnetic Cycles and Short-term Activity Variation". Astronomy & Astrophysics. 535: A55–A66. arXiv:1107.1748. Bibcode:2011A&A...535A..55D. doi:10.1051/0004-6361/201117148. S2CID 119192207. Archived from the original on 2015-05-29. Retrieved 2013-10-26.
  7. ^ "HD 7199". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-07.
  8. ^ a b "Approved names". NameExoworlds. Retrieved 2020-01-02.
  9. ^ a b "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  10. ^ Planet HD 7199 b on exoplanet.eu