text: 455,104,1448360409224843270,1377629674432438272,Jake Lustig-Yaeger,"New paper!  Although most known exoplanets are detected because they transit, the vast majority of exoplanets don’t transit. These are their stories. {Duh Dun}.   <LINK> <LINK> Last year, @kevinbstevenson wrote a paper introducing the concept of Planetary Infrared Excess, or PIE, as a novel method to characterize the atmospheres of transiting and non-transiting planets alike. <LINK> Exoplanets are MUCH cooler than stars. Fact. Because of this planets and stars emit light with a much different spectrum, and the PIE technique uses broad wavelength spectra to uniquely resolve both light sources, despite them being spatially unresolved. <LINK> In collaboration with @kevinbstevenson @mayorgalc @NorBidTheStars @_astronomay @izenplanet @mommascientist, we set out to determine how well the PIE technique will work to study the atmospheres of hot Jupiters. First, we cooked up a PIE model to investigate whether it’s possible to retrieve information about exoplanet atmospheres while simultaneously modeling the light emitted by the star and the much fainter planet. <LINK> Second, we examined whether or not stellar parameters can masquerade as planetary parameters or vice versa (i.e., are there significant planet-star degeneracies?). With broad enough wavelength coverage, we found the two sources to be separable and not degenerate. <LINK> We then repeated our analyses using different JWST instruments that cover different wavelength ranges and using different exposure times to identify the optimal use of JWST time/data. We found that a combination of NIRISS+NIRSpec+MIRI performs best. <LINK> Then we forgot everything we knew about the planet’s radius and tried to see if we could constrain it using PIE. Again, broad wavelength data using all three instruments is optimal. <LINK> All in all, it looks like PIE is on the menu for follow-up study and validation using JWST ERS and Cycle 1 observations! For more details including how we handled potential pitfalls, like exozodi dust and absolute flux calibration, check out the paper on the arxiv nearest you. <LINK> And here's a link to the accepted version of the paper on arxiv: <LINK> <LINK>",http://arxiv.org/abs/2110.02247,"To increase the sample size of future atmospheric characterization efforts, we build on the planetary infrared excess (PIE) technique that has been proposed as a means to detect and characterize the thermal spectra of transiting and non-transiting exoplanets using sufficiently broad wavelength coverage to uniquely constrain the stellar and planetary spectral components from spatially unresolved observations. We performed simultaneous retrievals of stellar and planetary spectra for the archetypal planet WASP-43b in its original configuration and a non-transiting configuration to determine the efficacy of the PIE technique for characterizing the planet's nightside atmospheric thermal structure and composition using typical out-of-transit JWST observations. We found that using PIE with JWST should enable the stellar and planetary spectra to be disentangled with no degeneracies seen between the two flux sources, thus allowing robust constraints on the planet's nightside thermal structure and water abundance to be retrieved. The broad wavelength coverage achieved by combining spectra from NIRISS, NIRSpec, and MIRI enables PIE retrievals that are within 10% of the precision attained using traditional secondary eclipse measurements, although mid-IR observations with MIRI alone may face up to 3.5 times lower precision on the planet's irradiation temperature. For non-transiting planets with unconstrained radius priors, we were able to identify and break the degeneracy between planet radius and irradiation temperature using data that resolved the peak of both the stellar and planetary spectra, thus potentially increasing the number of planets amenable to atmospheric characterization with JWST and other future mission concepts. ","Retrieving Exoplanet Atmospheres using Planetary Infrared Excess: