WASP-76b is a Hot Jupiter exoplanet orbiting the star WASP-76 in the constellation Pisces. Wasp-76b orbits its parent star at a distance of 0.033 AU with a period of 1.8 days. Its mass is 0.92 times that of Jupiter.[4][5][6] WASP-76b was discovered on October 21, 2013 and is the only planet in the WASP-76 system as of 2022. Wasp-76b equilibrium temperature is at 2,190 K (1,920 °C; 3,480 °F), and its measured day-side temperature is hotter at 2,500 ± 200 K (2,227 ± 200 °C; 4,040 ± 360 °F).[3]

WASP-76b

Artistic image of WASP-76b (based on 2020 data)
Discovery
Discovered by	R.G. West et al. (SuperWASP)[1]
Discovery date	October 21, 2013
Detection method	Transit (including secondary eclipses)
Orbital characteristics[2]
Semi-major axis	0.033±0.0005 AU
Eccentricity	0
Orbital period (sidereal)	1.809886±0.000001 d
Inclination	88.0°±1.6°
Star	WASP-76
Physical characteristics
Mean radius	1.83±0.06 RJ
Mass	0.92±0.03 MJ
Temperature	2500±200 K[3]

This article's tone or style may not reflect the encyclopedic tone used on Wikipedia. (March 2022)

Atmospheric composition

Data from the Hubble and Spitzer Space Telescopes indicates the presence of titanium oxide and traces of water inside the planet's atmosphere.[7] Higher-resolution spectra have featured ionized Lithium (Li), Sodium (Na), magnesium (Mg), calcium (Ca), manganese (Mn), potassium (K), and iron (Fe). However, no ionized titanium (Ti), chromium (Cr), nickel (Ni), or molecular oxides of titanium (Ti), vanadium (V), or zirconium (Zr) were found in Wasp-76b atmosphere.[8] The presence of calcium (Ca) was confirmed in 2021 by the Gemini North Observatory.[9][10][11] In 2022, the element barium (Ba) was also detected.[12]

The atmosphere of WASP-76b is cloudy and primarily grey, with a significant amount of thermal incandescence.[13]

Iron rain speculation

In March of 2020, initial spectroscopic findings indicated the presence of neutral iron. Therefore, it was speculated that if the temperature on Wasp-76b could reach 2,400 °C (2,700 K; 4,400 °F), hot enough to vaporize neutral iron and cold enough to condense the vapor to 1,400 °C (1,700 K; 2,600 °F). So, the neutral iron could rain down like a liquid.[14]

In May 2020, the Hubble Space Telescope discovered that the light from a stellar companion distorted the previous spectrum of WASP-76b. Using data from a current, up-to-date spectrum, we have an updated atmospheric model; cloudy hydrogen-helium envelope, non-detection of previously reported neutral iron (including "iron rain"[15]), and only upper limits on oxides of titanium and vanadium.[13] By 2021, the controversy was resolved by demonstrating that the tentative iron condensation signal may also appear due to the temperature asymmetry between leading and trailing limbs. However, existing data does not allow distinguishing between the two scenarios.[16]

Planetary atmospheric circulation models for WASP-76b suggest dense cloud layers formed of aluminum oxide, neutral iron, or magnesium orthosilicate, but no significant nightside condensation of iron.[17]

See also

• WASP-7b
• WASP-12b
• WASP-121b

References

На других языках

[es] WASP-76b