Qatar-2

Last updated
Qatar-2
Observation data
Epoch J2000       Equinox J2000
Constellation Virgo
Right ascension 13h 50m 37.4100s [1]
Declination −06° 48 14.4199 [1]
Apparent magnitude  (V)13.3 [2]
Characteristics
Spectral type K5V [1]
Astrometry
Radial velocity (Rv)-23.55 km/s
Proper motion (μ)RA: -88.184 [1]   mas/yr
Dec.: -15.290 [1]   mas/yr
Parallax (π)5.4849 ± 0.0365  mas [3]
Distance 595 ± 4  ly
(182 ± 1  pc)
Details [4] [2]
Mass 0.727±0.024  M
Radius 0.7033±0.0080  R
Surface gravity (log g)4.601±0.018  cgs
Temperature 4645±50  K
Metallicity [Fe/H]0.13±0.1 [5]   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 [1]
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. [2] The star features a numerous and long-lived starspots, [4] and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection. [6]

Planetary system

In 2011 a transiting superjovian planet Qatar-2b was detected by the Qatar Exoplanet Survey. [2] The planet has a large measured temperature difference between dayside (1368±32 K) and nightside (724±135 K). [7] The planetary orbit is well aligned with the equatorial plane of the star, [5] misalignment angle equal to 4.3±4.5◦. [8] No orbital decay was detected. [9] The color of planetary atmosphere is blue due to Rayleigh scattering of light, [8] and albedo is very low, being below 0.06. [9]

An additional massive companion on wide orbit was suspected in 2011, [2] but search utilizing transit-timing variation method has yielded zero results in 2017. [4]

The Qatar-2 planetary system [2] [4]
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

Related Research Articles

WASP-6, also officially named Márohu, is a type-G yellow dwarf star located about 651 light-years away in the Aquarius constellation. Dim at magnitude 12, it is visible through a moderate sized amateur telescope. The star is about 80% of the size and mass of the Sun and it is a little cooler. Starspots in the WASP-6 system helped to refine the measurements of the mass and the radius of the planet WASP-6b.

<span class="mw-page-title-main">WASP-8</span> Star in the constellation of Sculptor

WASP-8 is a binary star system 294 light-years away. The star system is much younger than the Sun at 300 million to 1.2 billion years age, and is heavily enriched in heavy elements, having nearly twice the concentration of iron compared to the Sun.

WASP-5 is a magnitude 12 G-type main-sequence star located about 1,020 light-years away in the Phoenix constellation. The star is likely older than the Sun, slightly enriched in heavy elements and is rotating rapidly, being spun up by the tides raised by the giant planet on a close orbit.

HAT-P-11, also designated GSC 03561-02092 and Kepler-3, is a metal-rich orange dwarf star with a planetary system, 123 light-years away in the constellation Cygnus. This star is notable for its relatively large rate of proper motion. The apparent magnitude of this star is about 9.6, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night. The age of this star is about 6.5 billion years.

Qatar-1 is an orange main sequence star in the constellation of Draco.

HAT-P-20 is a K-type main-sequence star about 233 light-years away. The star has a strong starspot activity, and its equatorial plane is misaligned by 36+10
−12
° with the planetary orbit. Although star with a giant planet on close orbit is expected to be spun-up by tidal forces, only weak indications of tidal spin-up were detected.

HAT-P-16 is a F-type main-sequence star about 725 light-years away. The star has a concentration of heavy elements slightly higher than solar abundance, and low starspot activity. The survey in 2015 have failed to find any stellar companions to it. The spectral analysis in 2014 have discovered the HAT-P-16 has a carbon to oxygen molar ratio of 0.58±0.08, close to Sun`s value of 0.55.

WASP-50 is a G-type main-sequence star about 594 light-years away. The star is older than the Sun and slightly depleted in heavy elements compared to the Sun, and has a close to average starspot activity. Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by giant planet on close orbit.

WASP-46 is a G-type main-sequence star about 1,210 light-years away. The star is older than the Sun and is strongly depleted in heavy elements compared to the Sun, having just 45% of the solar abundance. Despite its advanced age, the star is rotating rapidly, being spun up by the tides raised by a giant planet on a close orbit.

GSC 03949-00967 is a G-type main-sequence star about 1179 light-years away. It is older than the Sun, yet is enriched by heavy elements compared to the Sun, having 160% of solar abundance.

WASP-72 is the primary of a binary star system. It is an F7 class dwarf star, with an internal structure just on the verge of the Kraft break. It is orbited by a planet WASP-72b. The age of WASP-72 is younger than the Sun at 3.55±0.82 billion years.

BD+00 316 is an ordinary star with a close-orbiting planetary companion in the equatorial constellation of Cetus. It is also known as WASP-71 since 2019; BD+00 316 is the stellar identifier from the Bonner Durchmusterung catalogue. With an apparent visual magnitude of 10.56, it is too faint to be visible to the naked eye. This star is located at a distance of 1,160 light-years based on parallax measurements, and is drifting further away with a heliocentric radial velocity of 7.7 km/s.

WASP-64 is a star about 1200 light-years away. It is a G7 class main-sequence star, orbited by a planet WASP-64b. It is younger than the Sun at 3.6±1.6 billion years, and it has a metal abundance similar to the Sun. The star is rotating rapidly, being spun up by the giant planet in a close orbit.

WASP-60 is a F-type main-sequence star about 1420 light-years away. The stars age is much younger than the Sun's at 1.7±0.5 billion years. WASP-60 is enriched in heavy elements, having 180% of the solar abundance of iron. The star does not have noticeable starspot activity, an unexpected observation for a relatively young star. The age of WASP-60 determined by different methods is highly discrepant though, and it may actually be an old star which experienced an episode of spin-up in the past.

WASP-52 is a K-type main-sequence star about 570 light-years away. It is older than the Sun at 10.7+1.9
−4.5
billion years, but it has a similar fraction of heavy elements. The star has prominent starspot activity, with 3% to 14% of the stellar surface covered by areas 575±150 K cooler than the rest of the photosphere.

WASP-41 is a G-type main-sequence star. Its surface temperature is 5450±150 K. WASP-41 is similar to the Sun in its concentration of heavy elements, with a metallicity Fe/H index of −0.080±0.090, but is much younger at an age of 2.289±0.077 billion years. The star does exhibit strong starspot activity, with spots covering 3% of the stellar surface.

WASP-69, also named Wouri, is a K-type main-sequence star 164 light-years away. Its surface temperature is 4782±15 K. WASP-69 is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.10±0.01, and is much younger than the Sun at 2 billion years. The data regarding starspot activity of WASP-69 are inconclusive, but spot coverage of the photosphere may be very high.

WASP-88 is a F-type main-sequence star. Its surface temperature is 6450±61 K. WASP-88 is similar to the Sun in its concentration of heavy elements, with a metallicity Fe/H index of 0.03±0.04, and is younger at an age of 3.0±1.3 billion years.

WASP-84, also known as BD+02 2056, is a G-type main-sequence star 327 light-years away in the constellation Hydra. Its surface temperature is 5350±31 K and is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.05±0.02. It is rich in carbon and depleted of oxygen. WASP-84's age is probably older than the Sun at 8.5+4.1
−5.5
billion years. The star appears to have an anomalously small radius, which can be explained by the unusually high helium fraction or by it being very young.

WASP-80 is a K-type main-sequence star about 162 light-years away from Earth. The star's age is much younger than the Sun's at 1.352±0.222 billion years. WASP-80 could be similar to the Sun in concentration of heavy elements, although this measurement is highly uncertain.

References

  1. 1 2 3 4 5 6 Qatar 2 -- Star
  2. 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
  3. 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.
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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