Qatar-2 is aK-type main-sequence star about 595 light-years away in the constellation ofVirgo. The star is much older than Sun, and has a concentration of heavy elements similar tosolar abundance.[3] The star features a numerous and long-livedstarspots,[6] and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection.[9]
In 2011 atransitingsuperjovian planetQatar-2b was detected by theQatar Exoplanet Survey.[3] The planet has a large measured temperature difference between dayside1,368±32 K and nightside724±135 K.[10] The planetary orbit is well aligned with the equatorial plane of the star,[7] misalignment angle equal to4.3°±4.5°.[11] No orbital decay was detected.[12] The color of planetary atmosphere is blue due toRayleigh 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 utilizingtransit-timing variation method has yielded zero results in 2017.[6]
^abcdefBryan, 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,S2CID118627543
^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,S2CID247778438
^abMancini, 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,S2CID119203713
^abDai, 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,S2CID56019135
