Qatar-2

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Qatar-2
Observation data
Epoch J2000       Equinox J2000
Constellation Virgo [1]
Right ascension 13h 50m 37.4100s [2]
Declination −06° 48′ 14.422″ [2]
Apparent magnitude  (V)13.3 [3]
Characteristics
Spectral type K5V [4]
Astrometry
Radial velocity (Rv)−23.55 [5] km/s
Proper motion (μ)RA: −88.171 [2] mas/yr
Dec.: −15.187 [2] mas/yr
Parallax (π)5.4023±0.0195  mas [2]
Distance 604 ± 2  ly
(185.1 ± 0.7  pc)
Details [6] [3]
Mass 0.727±0.024  M☉
Radius 0.7033±0.0080  R☉
Surface gravity (log g)4.601±0.018  cgs
Temperature 4,645±50  K
Metallicity [Fe/H]0.13±0.1 [7]   dex
Rotation 18.0±0.2
Rotational velocity (v sin i)2.0±0.2 km/s
Age 9  Gyr
Other designations
Gaia DR2 3620030644476623616, GSC 04974-00112, 2MASS J13503740-0648145 [8]
Database references
SIMBAD data

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 system [3] [6]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 2.466±0.062  MJ 0.02136±0.000241.33711677±0.00000010088.99±0.20° 1.115±0.013  RJ

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. 1 2 3 4 5 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. 1 2 3 4 5 6 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. 1 2 3 4 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. 1 2 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. 1 2 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. 1 2 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


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