Article · Wikipedia archive · Last revised Aug 9, 2026

Qatar-2

Qatar-2 is a K-type main-sequence star about 595 light-years away in the constellation of Virgo. The star is much older than Sun, and has a concentration of heavy elements similar to solar abundance. The star features a numerous and long-lived starspots, and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection.

Last revised
Aug 9, 2026
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≈ 4 min
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Qatar-2
Observation data
Epoch J2000      Equinox ICRS
Constellation Virgo1
Right ascension 13h 50m 37.4100s2
Declination −06° 48′ 14.422″2
Apparent magnitude (V) 13.33
Characteristics
Evolutionary stage main sequence2
Spectral type K5V4
Astrometry
Radial velocity (Rv)−23.555 km/s
Proper motion (μ) RA: −88.1712 mas/yr
Dec.: −15.1872 mas/yr
Parallax (π)5.4023±0.0195 mas2
Distance604 ± 2 ly
(185.1 ± 0.7 pc)
Details63
Mass0.727±0.024 M☉
Radius0.7033±0.0080 R☉
Surface gravity (log g)4.601±0.018 cgs
Temperature4,645±50 K
Metallicity [Fe/H]0.13±0.17 dex
Rotation18.0±0.2
Rotational velocity (v sin i)2.0±0.2 km/s
Age9 Gyr
Other designations
GSC 04974-00112, 2MASS J13503740-0648145, Gaia DR2 36200306444766236168
Database references
SIMBADdata

Qatar-2 is a K-type main-sequence star about 595 light-years away in the constellation of Virgo. The star is much older than Sun, and has a concentration of heavy elements similar to solar abundance.3 The star features a numerous and long-lived starspots,6 and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection.9

Planetary system

In 2011 a transiting superjovian planet Qatar-2b was detected by the Qatar Exoplanet Survey.3 The planet has a large measured temperature difference between dayside 1,368±32 K and nightside 724±135 K.10 The planetary orbit is well aligned with the equatorial plane of the star,7 misalignment angle equal to 4.3°±4.5°.11 No orbital decay was detected.12 The color of planetary atmosphere is blue due to Rayleigh scattering of light,11 and albedo is very low, being below 0.06.12

An additional massive companion on wide orbit was suspected in 2011,3 but search utilizing transit-timing variation method has yielded zero results in 2017.6

The Qatar-2 planetary system36
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination
(°) 		Radius
b 2.466±0.062 MJ 0.02136±0.00024 1.33711677±0.00000010 0 88.99±0.20 1.115±0.013 RJ
References

References

  1. Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. Bryan, Marta L.; Alsubai, Khalid A.; Latham, David W.; Parley, Neil R.; Collier Cameron, Andrew; Quinn, Samuel N.; Carter, Joshua A.; Fulton, Benjamin J.; Berlind, Perry; Brown, Warren R.; Buchhave, Lars A.; Calkins, Michael L.; Esquerdo, Gilbert A.; Fűrész, Gábor; Jørgensen, Uffe Gråe; Horne, Keith D.; Stefanik, Robert P.; Street, Rachel A.; Torres, Guillermo; West, Richard G.; Dominik, Martin; Harpsøe, Kennet B. W.; Liebig, Christine; Calchi Novati, Sebastiano; Ricci, Davide; Skottfelt, Jesper F. (2011), "Qatar-2: A K dwarf orbited by a transiting hot Jupiter and a more massive companion in an outer orbit", The Astrophysical Journal, 750: 84, arXiv:1110.5912, doi:10.1088/0004-637X/750/1/84, S2CID 118627543
  4. Dressing, Courtney D.; Newton, Elisabeth R.; Schlieder, Joshua E.; Charbonneau, David; Knutson, Heather A.; Vanderburg, Andrew; Sinukoff, Evan (2017). "Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. I. Classifying Low-mass Host Stars Observed during Campaigns 1-7". The Astrophysical Journal. 836 (2): 167. arXiv:1701.00586. Bibcode:2017ApJ...836..167D. doi:10.3847/1538-4357/836/2/167.
  5. 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.
  6. Močnik, T.; Southworth, J.; Hellier, C. (2017), "Recurring sets of recurring starspot occultations on exoplanet-host Qatar-2", Monthly Notices of the Royal Astronomical Society, 471 (1): 394–403, arXiv:1608.07524, Bibcode:2017MNRAS.471..394M, doi:10.1093/mnras/stx1557, S2CID 119240651
  7. Esposito, M.; Covino, E.; Desidera, S.; Mancini, L.; Nascimbeni, V.; Zanmar Sanchez, R.; Biazzo, K.; Lanza, A. F.; Leto, G.; Southworth, J.; Bonomo, A. S.; Suárez Mascareño, A.; Boccato, C.; Cosentino, R.; Claudi, R. U.; Gratton, R.; Maggio, A.; Micela, G.; Molinari, E.; Pagano, I.; Piotto, G.; Poretti, E.; Smareglia, R.; Sozzetti, A.; Affer, L.; Anderson, D. R.; Andreuzzi, G.; Benatti, S.; Bignamini, A.; et al. (2017), "The GAPS Programme with HARPS-N at TNG. XIII. The orbital obliquity of three close-in massive planets hosted by dwarf K-type stars: WASP-43, HAT-P-20 and Qatar-2", Astronomy & Astrophysics, 601: A53, arXiv:1702.03136, Bibcode:2017A&A...601A..53E, doi:10.1051/0004-6361/201629720, S2CID 119341241
  8. "Qatar 2". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2025-05-05.
  9. Maxted, P. F. L.; Serenelli, A. M.; Southworth, J. (2015), "A comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars", Astronomy & Astrophysics, 577: A90, arXiv:1503.09111, Bibcode:2015A&A...577A..90M, doi:10.1051/0004-6361/201525774, S2CID 53324330
  10. May, E. M.; Stevenson, K. B.; Bean, Jacob L.; Bell, Taylor J.; Cowan, Nicolas B.; Dang, Lisa; Desert, Jean-Michel; Fortney, Jonathan J.; Keating, Dylan; Kempton, Eliza M.-R.; Komacek, Thaddeus D.; Lewis, Nikole K.; Mansfield, Megan; Morley, Caroline; Parmentier, Vivien; Rauscher, Emily; Swain, Mark R.; Zellem, Robert T.; Showman, Adam (2022), "A New Analysis of Eight Spitzer Phase Curves and Hot Jupiter Population Trends: Qatar-1b, Qatar-2b, WASP-52b, WASP-34b, and WASP-140b", The Astronomical Journal, 163 (6): 256, arXiv:2203.15059, Bibcode:2022AJ....163..256M, doi:10.3847/1538-3881/ac6261, S2CID 247778438
  11. Mancini, L.; Southworth, J.; Ciceri, S.; Tregloan-Reed, J.; Crossfield, I.; Nikolov, N.; Bruni, I.; Zambelli, R.; Henning, Th. (2014), "Physical properties, starspot activity, orbital obliquity, and transmission spectrum of the Qatar-2 planetary system from multi-colour photometry", Monthly Notices of the Royal Astronomical Society, 443 (3): 2391, arXiv:1406.6714, Bibcode:2014MNRAS.443.2391M, doi:10.1093/mnras/stu1286, S2CID 119203713
  12. Dai, Fei; Winn, Joshua N.; Yu, Liang; Albrecht, Simon (2016), "The Stellar Obliquity, Planet Mass, and Very Low Albedo of Qatar-2 from K2 Photometry", The Astronomical Journal, 153: 40, arXiv:1609.01314, doi:10.3847/1538-3881/153/1/40, S2CID 56019135