text: 328,8,1112737652602601477,70874545,Josh Lothringer,"New paper on the arXiv today: <LINK>! We explore the wacky world of ultra-hot Jupiters further by looking at how they change when around different type stars. This should be important since ultra-hot Jupiters are the most highly irradiated gaseous planets and are often around earlier-type host stars (e.g., KELT-9, the host star of the hottest Jovian exoplanet, is an A0, emitting ~50% of its flux in the UV). We find that planets of the same Teq around earlier-type host stars will have stronger, steeper inversions b/c of more short-wavelength (&lt;0.5 mu) absorption. Additionally, treating the star in NLTE also affects the modeled planet b/c of metal line depths. <LINK> This trend should be readily detectable by future observations. Such observations will see more muted transit spectra in planets around earlier-type host stars (b/c more H-) and larger brightness temperature variations in emission spectra. <LINK> Lastly, we took a closer look at what is making up the absorption at short-wavelengths, responsible for heating the atmosphere. Here we show that Fe, Fe+, Mg, and C are responsible for absorbing all the irradiation. Na, Ca, and K are important deeper. <LINK> If you're in Tucson, you can hear me talk about this *today* at the Theoretical Astrophysics Program graduate research prize colloquium at 3:30 in Kuiper 312!",https://arxiv.org/abs/1903.12183,"Ultra-hot Jupiters are the most highly irradiated gas giant planets, with equilibrium temperatures from 2000 to over 4000 K. Ultra-hot Jupiters are amenable to characterization due to their high temperatures, inflated radii, and short periods, but their atmospheres are atypical for planets in that the photosphere possesses large concentrations of atoms and ions relative to molecules. Here we evaluate how the atmospheres of these planets respond to irradiation by stars of different spectral type. We find that ultra-hot Jupiters exhibit temperature inversions that are sensitive to the spectral type of the host star. The slope and temperature range across the inversion both increase as the host star effective temperature increases due to enhanced absorption at short wavelengths and low pressures. The steep temperature inversions in ultra-hot Jupiters around hot stars result in increased thermal dissociation and ionization compared to similar planets around cooler stars. The resulting increase in H$^{-}$ opacity leads to a transit spectrum that has muted absorption features. The emission spectrum, however, exhibits a large contrast in brightness temperature, a signature that will be detectable with both secondary eclipse observations and high-dispersion spectroscopy. We also find that the departures from local thermodynamic equilibrium in the stellar atmosphere can affect the degree of heating caused by atomic metals in the planet's upper atmosphere. Additionally, we further quantify the significance of heating by different opacity sources in ultra-hot Jupiter atmospheres. ","The Influence of Host Star Spectral Type on Ultra-Hot Jupiter