ExoAtmospheres
IAC community database for exoplanet atmospheric observations

WASP-12 b

Planet status	Confirmed
Planet type	UltraHot Jupiter
Period	1.09141937 d
Mass	1.47 M_J 467.166 M⊕
Radius	1.9 R_J 21.28 R⊕
Semi major axis	0.02344 AU
Star name	WASP-12
Star distance	432.5 pc
Star teff	6360 K
Star radius	1.657 R☉
Temperature (calculated)	2593 K
V	11.69 mag
J	10.48 mag
K	10.19 mag
Alternate names
Exoplanet Encyclopaedia

Molecules

H: Detection	G-B: High resolution visible	Evidence for an Extended Hydrogen Outflow on WASP-12 b 2026, Morgan Saidel, Shreyas Vissapragada et al.	Evidence for extended H
H: Detection	G-B: High resolution visible	WASP-12b Exhibits Persistent In-Transit H$α$ Absorption 2026, Shreyas Vissapragada, Fabienne Nail et al.	Hα absorption evidences Roche Lobe Overflow and the presence of a toroidal structure around the host star.
He: Detection	G-B:Low resolution IR	The First Dedicated Survey of Atmospheric Escape from Planets Orbiting F Stars 2025, Morgan Saidel, Shreyas Vissapragada et al.	>3sigma detection of He excess with narrow band photometry
H: No detection Ca: Upper limit Fe: Upper limit Fe+: Upper limit Cr: Upper limit Mg: Upper limit Ti: Upper limit TiO: Upper limit Ti+: Upper limit	G-B: High resolution visible	PEPSI's non-detection of escaping hydrogen and metal lines adds to the enigma of WASP-12 b 2024, Anusha Pai Asnodkar, Ji Wang et al.	Two transits with LBT/PEPSI. No detection of Halpha and Hbeta.
Albedo: 0.35 Phase curve: Yes Dayside Temperature (occultation): 2900 K	Spitzer	A Comprehensive Analysis Spitzer 4.5 $μ$m Phase Curve of Hot Jupiters 2024, Lisa Dang, Taylor J. Bell et al.	Dayside and nightside temperatures from phase curve at 4.5 um.
Featureless spectra: Detection He: Upper limit	G-B: High resolution visible	The elusive atmosphere of WASP-12 b / High-resolution transmission spectroscopy with CARMENES 2024, S. Czesla, M. Lampón et al.
CO2: Detection H2O: Detection	HST WFC3	Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse 2022, Quentin Changeat, Billy Edwards et al.
Phase curve: Yes	TESS	Visible-light Phase Curves from the Second Year of the TESS Primary Mission 2021, Ian Wong, Daniel Kitzmann et al.	Secondary eclipse (443+/-86 ppm), planetary phase curve, marginal eastward offset, and stellar ellipsoidal distortion.
Phase curve: Yes	Spitzer	Mass loss from the exoplanet WASP-12b inferred from Spitzer phase curves 2019, Bell, Taylor J., Zhang, Michael et al.	Evidence for CO emission from gas lost by the planet
H: Detection Na: Detection	G-B: High resolution visible	Hydrogen and Sodium Absorption in the Optical Transmission Spectrum of WASP-12b 2018, Jensen, Adam G., Cauley, P. Wilson et al.	Detection of H-alpha and Na I doublet with the Hobby-Eberly Telescope
He: No detection	HST WFC3	Non-Detection of a Helium Exosphere for the Hot Jupiter WASP-12b 2018, Laura KreidbergAntonija Oklopčić	There is no significant increase in transit depth at 10833 Angs.
H2O: Detection	HST WFC3	A Population Study of Gaseous Exoplanets 2018, Tsiaras, A., Waldmann, I. P. et al.
Albedo: 0.064	HST STIS	The Very Low Albedo of WASP-12b from Spectral Eclipse Observations with Hubble 2017, Bell, Taylor J., Nikolov, Nikolay et al.	Albedo measured to be < 0.064 (97.5% confidence level) across 290-570 nm
	HST WFC3	A Detection of Water in the Transmission Spectrum of the Hot Jupiter WASP-12b and Implications for Its Atmospheric Composition 2015, Kreidberg, Laura, Line, Michael R. et al.	H2O absorption detected at 7 sigma
TiO: No detection	HST WFC3	HST hot Jupiter transmission spectral survey: evidence for aerosols and lack of TiO in the atmosphere of WASP-12b 2013, D. K. Sing, A. Lecavelier des Etangs et al.
Fe+: Detection	HST STIS	Near-ultraviolet Absorption, Chromospheric Activity, and Star-Planet Interactions in the WASP-12 system 2012, Haswell, C. A., Fossati, L. et al.	Detection done with HST COS, not STIS, but HST COS not available. COS should be added to the list.
Mg+: Detection	HST STIS	Metals in the Exosphere of the Highly Irradiated Planet WASP-12b 2010, Fossati, L., Haswell, C. A. et al.	Detection done with HST COS, not STIS, but HST COS not available. COS should be added to the list.