  Ultra-hot Jupiters with equilibrium temperature greater than 2000K are
uniquely interesting targets as they provide us crucial insights into how
atmospheres behave under extreme conditions. This class of giant planets
receives intense radiation from their host star and usually has strongly
irradiated and highly inflated atmospheres. At such high temperature, cloud
formation is expected to be suppressed and thermal dissociation of water vapor
could occur. We observed the ultra-hot Jupiter WASP-76b with 7 transits and 5
eclipses using the Hubble Space Telescope (HST) and $Spitzer$ for a
comprehensive study of its atmospheric chemical and physical processes. We
detect TiO and H$_2$O absorption in the optical and near-infrared transit
spectrum. Additional absorption by a number of neutral and ionized heavy metals
like Fe, Ni, Ti, and SiO help explain the short wavelength transit spectrum.
The secondary eclipse spectrum shows muted water feature but a strong CO
emission feature in Spitzer's 4.5 $\mu$m band indicating an inverted
temperature pressure profile. We analyzed both the transit and emission
spectrum with a combination of self-consistent PHOENIX models and retrieval
models (ATMO $\&$ PLATON). Both spectra are well fitted by the self-consistent
PHOENIX forward atmosphere model in chemical and radiative equilibrium at solar
metallicity, adding to the growing evidence that both TiO/VO and NUV heavy
metals opacity are prominent NUV-optical opacity sources in the stratospheres
of ultra-hot Jupiters.
