Tuiren (star)

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Diagram showing star positions and boundaries of the Canes Venatici constellation and its surroundings
Cercle rouge 100%.svg
Location of Tuiren (circled) within Canes Venatici
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Canes Venatici
Right ascension 12h 33m 03s[1]
Declination +44° 54′ 55″
Apparent magnitude (V) 12.26
Spectral type G
Radial velocity (Rv)-16.434 km/s
Proper motion (μ) RA: -11.641 mas/yr
Dec.: 8.065 mas/yr
Parallax (π)3.3678 ± 0.0258 mas
Distance968 ± 7 ly
(297 ± 2 pc)
Mass1.022 ± 0.049 M
Radius1.096 ± 0.056 R
Temperature5580 ± 100.0 K
Metallicity [Fe/H]0.26 ± 0.08 dex
Age6.6 ± 1.8 Gyr
Other designations
2MASS J12330390+4454552, Gaia DR1 1541532207133249920
Database references

Tuiren,[2] also referred to as HAT-P-36, is a 12th magnitude G-type main-sequence star estimated to be approximately 1,034 light-years away from Earth in the constellation Canes Venatici. Tuiren is too faint to be seen with the naked eye, but it is possible to view it with binoculars or a small telescope. In 2012 a hot Jupiter-type exoplanet was discovered orbiting Tuiren with an orbital period of about 1.3 Earth days.[3] In December 2019, HAT-P-36 was named Tuiren and its planetary companion, HAT-P-36b, was named Bran as a result of Ireland's contribution to the 2019 NameExoWorlds campaign.[4] Bran has a mass approximately 1.8 times that of Jupiter and a radius 1.2 times larger.


Tuiren (centre) as viewed in the Sloan Digital Sky Survey. The bright star to the top-left is TYC 3020-2195-1, an A-type main-sequence star approximately 3,156 light-years away.[5]

Tuiren and its planet are named after characters from The Birth of Bran, a story in the book Irish Fairy Tales by James Stephens. The book is a re-telling of various stories from Irish folklore. Tuiren was the aunt of the mythical hero Fionn mac Cumhaill and was turned into a hound by the fairy Uchtdealbh after Tuiren married her husband. Bran and Sceólan were the two puppies mothered by Tuiren while she was a dog. They were cousins of Fionn mac Cumhaill. The names were proposed by John Murphy, a teacher at Regina Mundi College, Cork.[6]


The Tuiren[1] planetary system
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
Bran ≥1.832±0.099 MJ 0.0238±0.0004 1.327347±0.000003 0.063±0.032 86±1.3° 1.264±0.071 RJ

Bran (HAT-P-36b) was discovered in 2012 by the HATNet Project using the transit method.[3] A search for transit timing variation did not result in detection of additional planets in the system as at 2021.[7] Surprisingly, a planetary orbital period increase by 0.014 seconds per year was detected by 2021.[8]

Size comparison
Jupiter Bran
Jupiter Exoplanet


  1. ^ a b "Planet HAT-P-36 b". Extrasolar Planets Encyclopaedia. Retrieved 24 July 2020.
  2. ^ "IAU100 NameExoWorlds Approved Names" (PDF). NameExoWorlds. International Astronomical Union. Retrieved 24 July 2020.
  3. ^ a b "HAT-P-36". Open Exoplanet Catalogue. Retrieved 24 July 2020.
  4. ^ Smith, Niall (29 September 2019). "Sky Matters: Ireland has the chance to name a star and a planet - any ideas?". Irish Examiner. Retrieved 24 July 2020.
  5. ^ "TYC 3020-2195-1". Centre de Données astronomiques de Strasbourg. SIMBAD. Retrieved 24 July 2020.
  6. ^ Gorey, Colm (18 December 2019). "Cork teacher names exoplanet and star after Irish mythical dogs". Silicon Republic. Retrieved 24 July 2020.
  7. ^ Probing Transit Timing Variations of Three Hot-Jupiters: HATP-36b, HATP-56b, and WASP-52b, 2021, arXiv:2111.05220
  8. ^ Analysis of The Most Precise Light Curves of HAT-P-36 Detrended From Spot Signals, 2021, arXiv:2111.11531