HD 27894

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HD 27894
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Reticulum
Right ascension 04h 20m 47.04716s[1]
Declination –59° 24′ 39.0184″[1]
Apparent magnitude (V) 9.42
Characteristics
Spectral type K2 V[2]
U−B color index +0.90[3]
B−V color index +1.005[3]
Astrometry
Proper motion (μ) RA: +182.16[1] mas/yr
Dec.: +271.77[1] mas/yr
Parallax (π) 22.79 ± 0.85[1] mas
Distance 143 ± 5 ly
(44 ± 2 pc)
Details
Mass 0.86 ± 0.06[4] M
Surface gravity (log g) 4.54 ± 0.05[4] cgs
Temperature 4920 ± 45[4] K
Metallicity [Fe/H] +0.20[5] dex
Age 7.7 ± 2.3[4] Gyr
Other designations
CD−59° 829, HD 27894, HIP 20277, LTT 1953.[3]
Database references
SIMBAD data

HD 27894 is a 9th magnitude star located approximately 138 light years away in the constellation of Reticulum. It is an orange dwarf (spectral type K2V), a type dimmer and cooler than our Sun.

In 2005, the Geneva Extrasolar Planet Search Team announced some of the discoveries of an extrasolar planet orbiting the star.[6] In 2017, the discovery of two additional exoplanets was announced. One is very close to the star like the one discovered earlier, while the other one orbits the star at a much larger distance. It is the first system where such a large gap between orbital distances has been found.[7][8]

The HD 27894 planetary system[6]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b >0.66 MJ 0.125 18.02 ± 0.02 0.047 ± 0.010
c >0.16 MJ 0.198 36.1 ± 0.2 0.02 ± 0.02
d >5.4 MJ 5.4 5200 ± 100 0.39 ± 0.05

See also[edit]

References[edit]

  1. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 
  2. ^ Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H. LCCN 78010745. 
  3. ^ a b c "LTT 1953 -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-02-05 
  4. ^ a b c d Trevisan, M.; et al. (November 2011), "Analysis of old very metal rich stars in the solar neighbourhood", Astronomy & Astrophysics, 535: A42, arXiv:1109.6304Freely accessible, Bibcode:2011A&A...535A..42T, doi:10.1051/0004-6361/201016056 . See table 13.
  5. ^ Sousa, S. G.; et al. (August 2008), "Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes", Astronomy and Astrophysics, 487 (1): 373–381, arXiv:0805.4826Freely accessible, Bibcode:2008A&A...487..373S, doi:10.1051/0004-6361:200809698 
  6. ^ a b Moutou, C.; et al. (2005). "The HARPS search for southern extra-solar planets IV. Three close-in planets around HD 2638, HD 27894 and HD 63454". Astronomy and Astrophysics. 439 (1): 367–373. Bibcode:2005A&A...439..367M. doi:10.1051/0004-6361:20052826. 
  7. ^ Trifonov, T.; Kürster, M.; Zechmeister, M.; Zakhozhay, O. V.; Reffert, S.; Lee, M. H.; Rodler, F.; Vogt, S. S.; Brems, S. S. (2017). "Three planets around HD 27894. A close-in pair with a 2:1 period ratio and an eccentric Jovian planet at 5.4 AU". Astronomy & Astrophysics. 602: L8. arXiv:1706.00509Freely accessible [astro-ph.EP]. Bibcode:2017A&A...602L...8T. doi:10.1051/0004-6361/201731044. 
  8. ^ Tomasz Nowakowski (June 12, 2017). "Two new massive planets detected around the star HD 27894". Retrieved June 12, 2017. 

External links[edit]

Coordinates: Sky map 04h 20m 47.0473s, −59° 24′ 39.014″