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WASP-33b

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WASP-33b
Discovery[1]
Discovered byWASP
Discovery date2010
Transit
Orbital characteristics
0.02555 ± 0.00017 AU (3,822,200 ± 25,432 km) [1]
1.21987089 ± 0.00000015 days (105,396.845 ± 0.013 s; 29.2769014 ± 3.6×10−6 h) [2]
Inclination87.67±1.81°[1]
Semi-amplitude0.59 km/s (1,300 mph) [1]
StarHD 15082
Physical characteristics
1.497±0.095 RJ[1]
Mass2.81±0.53 MJ[3]
Albedo0.369±0.050[3]
Temperature2,710 ± 50 K (2,440 ± 50.0 °C; 4,420 ± 90.0 °F) [1]

WASP-33b is an extrasolar planet orbiting the star HD 15082. It was the first planet discovered to orbit a Delta Scuti variable star. With a semimajor axis of 0.026 AU (3.9 million km; 2.4 million mi) and a mass likely greater than Jupiter's,[1] it belongs to the hot Jupiter class of planets.

Discovery

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In 2010, the SuperWASP project announced the discovery of an extrasolar planet orbiting the star HD 15082. The discovery was made by detecting the transit of the planet as it passes in front of its star, an event that occurs every 1.22 days.

Orbit

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A study in 2012, utilizing the Rossiter–McLaughlin effect, determined the planetary orbit is strongly misaligned with the equatorial plane of the star, misalignment equal to −107.7±1.6°, making the orbit of WASP-33b retrograde.[4] The periastron node is precessing with a period of 709+33
−34 years.[5]

Physical characteristics

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Limits from radial velocity measurements imply it has less than 4.1 times the mass of Jupiter.[1] The exoplanet orbits so close to its star that its surface temperature is about 3,200 °C (5,790 °F).[6] The transit was later recovered in Hipparcos data.[7]

Atmosphere

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In June 2015, NASA reported the exoplanet has a stratosphere, and the atmosphere contains titanium monoxide, which creates the stratosphere. Titanium oxide is one of only a few compounds that is a strong absorber of visible and ultraviolet radiation, which heats the atmosphere, and is able to exist in a gas state in a hot atmosphere.[8][9] This was later confirmed using high-resolution spectroscopy technique with the data taken by High Dispersion Spectrograph mounted on the 8.2 m Subaru telescope.[10] The detection titanium oxide was not be able to be reproduced with the higher quality data obtained by 2020 although with different setting of observations. Only upper limit of titanium oxide volume mixing rate equal to 1 ppb can be obtained.[11] Later research reconfirmed the existence of titanium oxide in the atmosphere of WASP-33b, although in concentrations not detectable by HARPS-N.

The neutral iron [12] [13] and silicon[14] were also detected.

Atmosphere of WASP-33b was detected by monitoring light as the planet passed behind its star (top)—higher temperatures result in the low stratosphere due to molecules absorbing radiation from the star (right)—lower temperatures at higher altitudes would result if there were no stratosphere (left)[8]

In 2020, with the detection of secondary eclipses (when the planet is blocked by its star), the mass of the planet along with temperature profile across its surface was measured. WASP-33b has strong winds in its atmosphere, similar to Venus, shifting the hottest spot 28.7±7.1 degrees to the west. The averaged wind speed is 8.5+2.1
−1.9 km/s in the thermosphere.[15] The illuminated side brightness temperature is 3,014 ± 60 K (2,740.8 ± 60.0 °C; 4,965.5 ± 108.0 °F), while the nightside brightness temperature is 1,605 ± 45 K (1,331.8 ± 45.0 °C; 2,429.3 ± 81.0 °F).[3]

The atmospheric escape driven by hydrogen Balmer line absorption is relatively modest, totaling about one to ten Earth masses per billion years.[16]

The water in dayside atmosphere of WASP-33b is mostly dissociated to hydroxyl radicals due to high temperature, as planetary emission spectra indicated which was the first detected hydroxyl radicals on a planet outside the solar system.[17][18]

Non-Keplerian features of motion for WASP-33b

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In view of the high rotational speed of its parent star, the orbital motion of WASP-33b may be affected in a measurable way by the huge oblateness of the star and effects of general relativity.

First, the distorted shape of the star makes its gravitational field deviate from the usual Newtonian inverse-square law. The same is true for the Sun, and part of the precession of the orbit of Mercury is due to this effect. However, it is estimated to be greater for WASP-33b.[19]

Other effects will also be greater for WASP-33b. In particular, precession due to general relativistic frame-dragging should be greater for WASP-33b than for Mercury, where it is so far too small to have been observed. It has been argued that the oblateness of HD 15082 could be measured at a percent accuracy from a 10-year analysis of the time variations of the planet's transits.[19] Effects due to the planet's oblateness are smaller by at least one order of magnitude, and they depend on the unknown angle between the planet's equator and the orbital plane, perhaps making them undetectable. The effects of frame-dragging are slightly too small to be measured by such an experiment.

Nodal precession of WASP-33b, caused by oblateness of the parent star, was measured by 2021. The gravitational quadrupole moment of the HD 15082 was found to be equal to 6.73±0.22×10−5. The non-Keplerian precession is expected to be 500 times smaller, yet to be detected.[20]

See also

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References

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  1. ^ a b c d e f g h Collier Cameron, A.; et al. (2010). "Line-profile tomography of exoplanet transits - II. A gas-giant planet transiting a rapidly rotating A5 star". Monthly Notices of the Royal Astronomical Society. 407 (1): 507. arXiv:1004.4551. Bibcode:2010MNRAS.407..507C. doi:10.1111/j.1365-2966.2010.16922.x. S2CID 11989684.
  2. ^ Zhang, Michael; et al. (2017). "Phase curves of WASP-33b and HD 149026b and a New Correlation Between Phase Curve Offset and Irradiation Temperature". The Astronomical Journal. 155 (2): 83. arXiv:1710.07642. Bibcode:2018AJ....155...83Z. doi:10.3847/1538-3881/aaa458. S2CID 54755276.
  3. ^ a b c von Essen, C.; Mallonn, M.; Borre, C. C.; Antoci, V.; Stassun, K. G.; Khalafinejad, S.; Tautvaivsiene, G. (2020). "TESS unveils the phase curve of WASP-33b. Characterization of the planetary atmosphere and the pulsations from the star". Astronomy & Astrophysics. A34: 639. arXiv:2004.10767. Bibcode:2020A&A...639A..34V. doi:10.1051/0004-6361/202037905. S2CID 216080995.
  4. ^ Albrecht, Simon; Winn, Joshua N.; et al. (August 30, 2012). "Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments". The Astrophysical Journal. 757 (1): 18. arXiv:1206.6105. Bibcode:2012ApJ...757...18A. doi:10.1088/0004-637X/757/1/18. S2CID 17174530. Retrieved March 28, 2022.
  5. ^ Watanabe, Noriharu; Narita, Norio; Palle, Enric (March 3, 2022). "Nodal Precession of WASP-33b for Eleven Years by Doppler Tomographic and Transit Photometric Observations". Monthly Notices of the Royal Astronomical Society. arXiv:2203.02003. doi:10.1093/mnras/stac620.
  6. ^ "Hottest planet is hotter than some stars". Retrieved 2015-06-12.
  7. ^ McDonald, I.; Kerins, E. (2018). "Pre-discovery transits of the exoplanets WASP-18b and WASP-33b from Hipparcos". Monthly Notices of the Royal Astronomical Society. 477 (1): L21. arXiv:1803.06187. Bibcode:2018MNRAS.477L..21M. doi:10.1093/mnrasl/sly045. S2CID 49547292.
  8. ^ a b Northon, Karen, ed. (June 11, 2015). "NASA's Hubble Telescope Detects 'Sunscreen' Layer on Distant Planet". NASA.gov. Retrieved March 28, 2022.
  9. ^ Haynes, Korey; Mandell, Avi M.; et al. (June 12, 2015). "Spectroscopic Evidence for a Temperature Inversion in the Dayside Atmosphere of the Hot Jupiter WASP-33b". The Astrophysical Journal. 806 (2): 146. arXiv:1505.01490. Bibcode:2015ApJ...806..146H. doi:10.1088/0004-637X/806/2/146. S2CID 35485407. Retrieved March 28, 2022.
  10. ^ Nugroho, Stevanus K.; Kawahara, Hajime; Masuda, Kento; Hirano, Teruyuki; Kotani, Takayuki; Tajitsu, Akito (1 December 2017). "High-resolution Spectroscopic Detection of TiO and a Stratosphere in the Day-side of WASP-33b". The Astronomical Journal. 154 (6): 221. arXiv:1710.05276. Bibcode:2017AJ....154..221N. doi:10.3847/1538-3881/aa9433.
  11. ^ Herman, Miranda K.; Mooij, Ernst J. W. de; et al. (July 31, 2020). "Search for TiO and Optical Nightside Emission from the Exoplanet WASP-33b". The Astronomical Journal. 160 (2): 93. arXiv:2006.10743. Bibcode:2020AJ....160...93H. doi:10.3847/1538-3881/ab9e77. S2CID 219792767.
  12. ^ Nugroho, S. K.; Gibson, N. P.; De Mooij, E. J. W.; Herman, M. K.; Watson, C. A.; Kawahara, H.; Merrit, S. R. (2020), "Detection of Fe I Emission in the Dayside Spectrum of WASP-33b", The Astrophysical Journal Letters, 898 (2): L31, arXiv:2007.05508, Bibcode:2020ApJ...898L..31N, doi:10.3847/2041-8213/aba4b6, S2CID 220486401
  13. ^ Cont, D.; Yan, F.; Reiners, A.; Casasayas-Barris, N.; Mollière, P.; Pallé, E.; Henning, Th.; Nortmann, L.; Stangret, M.; Czesla, S.; López-Puertas, M.; Sánchez-López, A.; Rodler, F.; Ribas, I.; Quirrenbach, A.; Caballero, J. A.; Amado, P. J.; Carone, L.; Khaimova, J.; Kreidberg, L.; Molaverdikhani, K.; Montes, D.; Morello, G.; Nagel, E.; Oshagh, M.; Zechmeister, M. (2021), "Detection of Fe and evidence for TiO in the dayside emission spectrum of WASP-33b", Astronomy & Astrophysics, 651: A33, arXiv:2105.10230, Bibcode:2021A&A...651A..33C, doi:10.1051/0004-6361/202140732, S2CID 235125585
  14. ^ Cont, D.; Yan, F.; Reiners, A.; Nortmann, L.; Molaverdikhani, K.; Pallé, E.; Stangret, M.; Henning, Th.; Ribas, I.; Quirrenbach, A.; Caballero, J. A.; Zapatero Osorio, M. R.; Amado, P. J.; Aceituno, J.; Casasayas-Barris, N.; Czesla, S.; Kaminski, A.; López-Puertas, M.; Montes, D.; Morales, J. C.; Morello, G.; Nagel, E.; Sánchez-López, A.; Sedaghati, E.; Zechmeister, M. (2022), "Silicon in the dayside atmospheres of two ultra-hot Jupiters", Astronomy & Astrophysics, 657: L2, arXiv:2112.10461, Bibcode:2022A&A...657L...2C, doi:10.1051/0004-6361/202142776, S2CID 245302250
  15. ^ Wilson Cauley, P.; Wang, Ji; et al. (2021), "Time-resolved rotational velocities in the upper atmosphere of WASP-33 b", The Astronomical Journal, 161 (3): 152, arXiv:2010.02118, Bibcode:2021AJ....161..152C, doi:10.3847/1538-3881/abde43, S2CID 222132849
  16. ^ Yan, F.; Wyttenbach, A.; et al. (January 2021) [December 22, 2020]. "Detection of the hydrogen Balmer lines in the ultra-hot Jupiter WASP-33b". Astronomy & Astrophysics. 645: A22. arXiv:2011.07888. Bibcode:2021A&A...645A..22Y. doi:10.1051/0004-6361/202039302. ISSN 0004-6361. S2CID 226965524. Retrieved March 28, 2022.
  17. ^ Nugroho, Stevanus K.; Kawahara, Hajime; Gibson, Neale P.; De Mooij, Ernst J. W.; Hirano, Teruyuki; Kotani, Takayuki; Kawashima, Yui; Masuda, Kento; Brogi, Matteo; Birkby, Jayne L.; Watson, Chris A.; Tamura, Motohide; Zwintz, Konstanze; Harakawa, Hiroki; Kudo, Tomoyuki; Kuzuhara, Masayuki; Hodapp, Klaus; Ishizuka, Masato; Jacobson, Shane; Konishi, Mihoko; Kurokawa, Takashi; Nishikawa, Jun; Omiya, Masashi; Serizawa, Takuma; Ueda, Akitoshi; Vievard, Sébastien (2021), "First Detection of Hydroxyl Radical Emission from an Exoplanet Atmosphere: High-dispersion Characterization of WASP-33b Using Subaru/IRD", The Astrophysical Journal Letters, 910 (1): L9, arXiv:2103.03094, Bibcode:2021ApJ...910L...9N, doi:10.3847/2041-8213/abec71, S2CID 232110452
  18. ^ Wright, Sam O. M.; Nugroho, Stevanus K.; Brogi, Matteo; Gibson, Neale P.; de Mooij, Ernst J. W.; Waldmann, Ingo; Tennyson, Jonathan; Kawahara, Hajime; Kuzuhara, Masayuki; Hirano, Teruyuki; Kotani, Takayuki; Kawashima, Yui; Masuda, Kento; Birkby, Jayne L.; Watson, Chris A.; Tamura, Motohide; Zwintz, Konstanze; Harakawa, Hiroki; Kudo, Tomoyuki; Hodapp, Klaus; Jacobson, Shane; Konishi, Mihoko; Kurokawa, Takashi; Nishikawa, Jun; Omiya, Masashi; Serizawa, Takuma; Ueda, Akitoshi; Vievard, Sébastien; Yurchenko, Sergei N. (1 August 2023). "A Spectroscopic Thermometer: Individual Vibrational Band Spectroscopy with the Example of OH in the Atmosphere of WASP-33b". The Astronomical Journal. 166 (2): 41. arXiv:2305.11071. Bibcode:2023AJ....166...41W. doi:10.3847/1538-3881/acdb75.
  19. ^ a b Iorio, Lorenzo (2010-07-25), "Classical and relativistic node precessional effects in WASP-33b and perspectives for detecting them", Astrophysics and Space Science, 331 (2): 485–496, arXiv:1006.2707, Bibcode:2011Ap&SS.331..485I, doi:10.1007/s10509-010-0468-x, S2CID 119253639
  20. ^ Borsa, F.; et al. (2021), "The GAPS Programme at TNG", Astronomy & Astrophysics, 653: A104, arXiv:2105.12138, doi:10.1051/0004-6361/202140559, S2CID 235195940
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