WASP-21

Last updated
WASP 21 / Tangra
WASP-21.jpg
Size comparison between Sun and WASP-21
Observation data
Epoch J2000       Equinox J2000
Constellation Pegasus
Right ascension 23h 09m 58.25s [1]
Declination +18° 23′ 45.9″ [1]
Apparent magnitude  (V)11.58 ± 0.08 [1]
Characteristics
Spectral type G3V
Astrometry
Radial velocity (Rv)-89.45 [1]  km/s
Proper motion (μ)RA: 17.597 ± 0.074 [2]   mas/yr
Dec.: 18.867 ± 0.05 [2]   mas/yr
Parallax (π)3.8412 ± 0.0427  mas [2]
Distance 849 ± 9  ly
(260 ± 3  pc)
Absolute magnitude  (MV)4.97
Details
Mass 0.89 ± 0.071 [3]   M☉
Radius 1.136 ± 0.049 [3]   R☉
Surface gravity (log g)4.277 ± 0.025 [3]   cgs
Temperature 5800 ± 100 [1]   K
Metallicity -0.4 ± 0.1 [1]
Metallicity [Fe/H]-0.46 ± 0.11 [1]   dex
Rotational velocity (v sin i)1.5 ± 0.6 [1]  km/s
Age 12 ± 5 [1]   Gyr
Other designations
Tangra, GSC 01715-00679, 2MASS J23095825+1823459, Gaia DR2 2831084391023184128
Database references
SIMBAD data

WASP-21 is a G-type star (spectral type G3V) that is reaching the end of its main sequence lifetime [4] [5] approximately 850 light years from Earth in the constellation of Pegasus. The star is relatively metal-poor, having 40% of heavy elements compared to the Sun. [5] Kinematically, WASP-21 belongs to the thick disk of the Milky Way. [1] It has an exoplanet named WASP-21b. [6]

Contents

The survey in 2012 have failed to find any stellar companions to WASP-21. [7]

Naming

In 2019 the WASP-21 system was chosen as part of the NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named. WASP-21 was assigned to Bulgaria. The winning proposal named the star Tangra after a deity worshipped by the early Bulgars, and the planet Bendida after a deity worshipped by the Thracians. [8]

Planetary System

In 2010 WASP-21 was discovered to host a hot Jupiter type planet by the Wide Angle Search for Planets (WASP). [1] and confirmed by radial velocity by the WASP team in 2010.

Transit-timing variation analysis in 2015 did not find an additional planets in the system. [5]

In 2020, spectroscopic analysis has found the WASP-21 b atmosphere is mostly cloudless and contains sodium. [9]

The WASP-21 planetary system [3] [5]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Bendida0.276 ± 0.018  MJ 0.0499 ± 0.00134.3224820.0 [1] 86.97 ± 0.33° 1.162  RJ

Related Research Articles

<span class="mw-page-title-main">Wide Angle Search for Planets</span> Exoplanet search project

WASP or Wide Angle Search for Planets is an international consortium of several academic organisations performing an ultra-wide angle search for exoplanets using transit photometry. The array of robotic telescopes aims to survey the entire sky, simultaneously monitoring many thousands of stars at an apparent visual magnitude from about 7 to 13.

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.

WASP-10 is a star in the constellation Pegasus. The SuperWASP project has observed and classified this star as a variable star, perhaps due to the eclipsing planet.

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.

WASP-49 is a binary star system about 636 light-years away in the constellation Lepus. The two stars are separated by 443 AU. The primary is a G-type main-sequence star, with a surface temperature of 5,600 K. WASP-49 is depleted of heavy elements relative to the Sun. It has a metallicity Fe/H index of –0.23, meaning it has 59% the iron level of the Sun.

WASP-32 is a yellow main-sequence star in the constellation of Pisces. The star was given the formal name Parumleo in January 2020, Latin for small lion and referencing the national animal of Singapore.

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.

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-59 is a K-type main-sequence star about 379 light-years away. The star's age is essentially unconstrained by observations. WASP-59 is slightly depleted in heavy elements, having 70% of the solar abundance of iron. The star produces extremely low levels of ultraviolet light, indicating an absence of flare activity.

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 7 8 9 10 11 12 Bouchy, F.; Hebb, L.; Skillen, I.; Collier Cameron, A.; Smalley, B.; Udry, S.; Anderson, D. R.; Boisse, I.; Enoch, B.; Haswell, C. A.; Hébrard, G.; Hellier, C.; Joshi, Y.; Kane, S. R.; Maxted, P. F. L.; Mayor, M.; Moutou, C.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Simpson, E. K.; Smith, A. M. S.; Stempels, H. C.; Street, R.; Triaud, A. H. M. J.; West, R. G.; Wheatley, P. J. (2010). "WASP-21b: A hot-Saturn exoplanet transiting a thick disc star". Astronomy and Astrophysics. 519: A98. arXiv: 1006.2605 . Bibcode:2010A&A...519A..98B. doi:10.1051/0004-6361/201014817. S2CID   119182669.
  2. 1 2 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.
  3. 1 2 3 4 Ciceri, S.; Mancini, L.; Southworth, J.; Nikolov, N.; Bozza, V.; Bruni, I.; Calchi Novati, S.; d'Ago, G.; Henning, Th. (2013). "Simultaneous follow-up of planetary transits: Revised physical properties for the planetary systems HAT-P-16 and WASP-21". Astronomy & Astrophysics. 557: A30. arXiv: 1307.5874 . Bibcode:2013A&A...557A..30C. doi:10.1051/0004-6361/201321669. S2CID   55192357.
  4. ↑ Barros, S. C. C.; Pollacco, D. L.; Gibson, N. P.; Howarth, I. D.; Keenan, F. P.; Simpson, E. K.; Skillen, I.; Steele, I. A. (2011). "A lower mass for the exoplanet WASP-21b". Monthly Notices of the Royal Astronomical Society. 416 (4): 2593–2599. arXiv: 1106.2118 . Bibcode:2011MNRAS.416.2593B. doi: 10.1111/j.1365-2966.2011.19210.x . S2CID   56165266.
  5. 1 2 3 4 Seeliger, M.; Kitze, M.; Errmann, R.; Richter, S.; Ohlert, J. M.; Chen, W. P.; Guo, J. K.; Göğüş, E.; Güver, T.; Aydın, B.; Mottola, S.; Hellmich, S.; Fernandez, M.; Aceituno, F. J.; Dimitrov, D.; Kjurkchieva, D.; Jensen, E.; Cohen, D.; Kundra, E.; Pribulla, T.; Vaňko, M.; Budaj, J.; Mallonn, M.; Wu, Z.-Y.; Zhou, X.; Raetz, St.; Adam, C.; Schmidt, T. O. B.; Ide, A.; et al. (2015), "Ground-based transit observations of the HAT-P-18, HAT-P-19, HAT-P-27/WASP40 and WASP-21 systems", Monthly Notices of the Royal Astronomical Society, 451 (4): 4060–4072, arXiv: 1508.06215 , Bibcode:2015MNRAS.451.4060S, doi: 10.1093/mnras/stv1187 , S2CID   56034663
  6. ↑ "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. Retrieved 2022-12-10.
  7. ↑ Ginski, C.; Mugrauer, M.; Seeliger, M.; Eisenbeiss, T. (2012), "A lucky imaging multiplicity study of exoplanet host stars", Monthly Notices of the Royal Astronomical Society, 421 (3): 2498–2509, arXiv: 1202.4586 , Bibcode:2012MNRAS.421.2498G, doi: 10.1111/j.1365-2966.2012.20485.x , S2CID   118573795
  8. ↑ "Bulgaria | NameExoworlds". Name Exoworlds. 2019-12-17. Retrieved 2019-12-30.
  9. ↑ Chen, G.; Casasayas-Barris, N.; Pallé, E.; Welbanks, L.; Madhusudhan, N.; Luque, R.; Murgas, F. (2020), "Detection of Na in WASP-21b's lower and upper atmosphere", Astronomy & Astrophysics, 642: A54, arXiv: 2007.13429 , Bibcode:2020A&A...642A..54C, doi:10.1051/0004-6361/202038661, S2CID   220793336
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