WASP-33 b Atmosphere and properties

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WASP-33 b Atmosphere and properties

Post by Sirius_Alpha on 12th January 2011, 9:27 pm

Thermal emission from WASP-33b, the hottest known planet
http://arxiv.org/abs/1101.2432

We report ground-based observations at 0.91 microns of the occultation of the hot Jupiter WASP-33b by its A5 host star. We measure the planet to be 0.090 +/- 0.016 per cent as bright as its host star at 0.91 microns. This corresponds to a brightness temperature, T_B = 3466 +/- 130 K, significantly higher than the zero-albedo equilibrium temperature for both isotropic re-radiation (2711 +/- 50 K) and day-side only re-radiation (3224 +/- 60 K). This indicates that the heat redistribution from the day-side of WASP-33b to the night side is probably inefficient, and is suggestive of the presence of molecular emission. We also detected the stellar pulsations of WASP-33, which we model as the sum of three sinusoids, with periods of between 42 and 77 minutes and amplitudes of 0.4 to 0.9 mmag.


Last edited by Sirius_Alpha on 12th June 2015, 8:09 pm; edited 2 times in total

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Re: WASP-33 b Atmosphere and properties

Post by marasama on 18th January 2011, 3:40 pm

Wow, that temperature is in the dM range.

Even hotter than some dL stars.

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Re: WASP-33 b Atmosphere and properties

Post by Led_Zep on 11th June 2015, 6:27 pm

http://www.nasa.gov/press-release/nasa-s-hubble-telescope-detects-sunscreen-layer-on-distant-planet


NASA’s Hubble Space Telescope has detected a stratosphere, one of the primary layers of Earth’s atmosphere, on a massive and blazing-hot exoplanet known as WASP-33b.
The presence of a stratosphere can provide clues about the composition of a planet and how it formed. This atmospheric layer includes molecules that absorb ultraviolet and visible light, acting as a kind of “sunscreen” for the planet it surrounds. Until now, scientists were uncertain whether these molecules would be found in the atmospheres of large, extremely hot planets in other star systems.
These findings will appear in the June 12 issue of the Astrophysical Journal
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Re: WASP-33 b Atmosphere and properties

Post by Shellface on 12th June 2015, 6:25 pm

Something relevant (also new to me):

Mass of WASP-33b

We analysed an extended time series of high-resolution spectra of the delta Sct star WASP-33 with the aim to determine the effect of its planet WASP-33b. We found ten frequencies in the measured radial velocities. Three of them we can attribute to previously observed photometric oscillations due to non-radial pulsations. One frequency exactly agrees with the orbital period of the planet. The semi-amplitude of the corresponding variation is 304 ± 20 m s-1. This finding allows us to give a new estimate of the mass of WASP-33b of 2.1 ± 0.2 Jupiter masses. Its mean density probably is at least 0.6 g cm-3, a value that can be expected for a planet of its mass that orbits an A-type star in 1.22 d.
About 1 sigma lower than the tentative detection with TRES, and as they show, consistent with an expectable mass.

Interesting to see a method for considering pulsations while studying planetary RV variations. Ought to be useful in future.

(Also, it might be better to make this a general thread for WASP-33, since it's quite an important system)

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Re: WASP-33 b Atmosphere and properties

Post by Sirius_Alpha on 12th June 2015, 8:09 pm

Not a bad idea. Thread title changed.

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