HD 168746

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HD 168746
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension 18h 21m 49.7827s[1]
Declination −11° 55′ 21.652″[1]
Apparent magnitude (V) 7.95[2]
Spectral type G5V[2]
B−V color index 0.713[2]
Radial velocity (Rv)−25.606±0.0003[1] km/s
Proper motion (μ) RA: −22.946±0.054[1] mas/yr
Dec.: −68.402±0.040[1] mas/yr
Parallax (π)24.0282 ± 0.0573 mas[1]
Distance135.7 ± 0.3 ly
(41.62 ± 0.10 pc)
Absolute magnitude (MV)4.78[2]
Mass0.88±0.01 M
Luminosity1.10 L
Surface gravity (log g)4.50±0.15 cgs
Temperature5610±30 K
Metallicity [Fe/H]−0.06±0.05 dex
Rotational velocity (v sin i)1.0 km/s
Other designations
Alasia, BD-11° 4606, HIP 90004[3]
Database references
Exoplanet Archivedata

HD 168746 is an 8th magnitude star in the constellation of Serpens. It is very similar to our Sun, a yellow dwarf star (spectral class G5V). It is not visible to the unaided eye, but is easily visible with binoculars or a small telescope. In 2000 a planet was announced orbiting it.[4]

In 2019 the HD 168746 planetary system was chosen as part of the NameExoWorlds campaign organised by the International Astronomical Union to mark to 100th anniversary of the organisation. Each country was assigned a star and planet to be named with HD 168746 being assigned to Cyprus. The winning proposal named the star Alasia, an ancient name for Cyprus, and the planet Onasilos after an ancient Cypriot physician identified in the Idalion Tablet, one of the oldest known legal contracts.

Planetary system[edit]

The planet HD 168746 b was discovered by Exoplanet group at the Geneva Observatory with the radial velocity method using the CORALIE spectrograph on the Swiss 1.2-metre Leonard Euler Telescope.[2] At the time it was one of the lowest mass planets that had been discovered.

The HD 168746 planetary system[2]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b (Onasilus) >0.23 MJ 0.065 6.403 ± 0.001 0.081 ± 0.029

See also[edit]


  1. ^ a b c d e f 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 g Pepe, F.; et al. (2002). "The CORALIE survey for southern extra-solar planets VII. Two short-period Saturnian companions to HD 108147 and HD 168746". Astronomy and Astrophysics. 388 (2): 632–638. arXiv:astro-ph/0202457. Bibcode:2002A&A...388..632P. doi:10.1051/0004-6361:20020433. S2CID 13942987.
  3. ^ "HD 168746". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-04-05.
  4. ^ "Exoplanets Galore!" (Press release). Garching, Germany: European Southern Observatory. April 15, 2000. Retrieved December 30, 2012.

External links[edit]

Coordinates: Sky map 18h 21m 49.7832s, −11° 55′ 21.660″