text: 208,108,1062716984805244933,378228706,Hannah Wakeford,"Our #paper ""Disentangling the planet from the star in late type M dwarfs: A case study of TRAPPIST-1g"" is out <LINK> We use the star to work out various possible contrast effects, and the geometry of the transit to rule them out. Then let the planet decide! <LINK> In this study we find that #TRAPPIST1 is best described as a 0.08Msun, 0.117Rsun, M8V star with a photospheric Teff=2400K, with ~35% @ 3000K & &lt;3% @ ~5800K Bottom panel - Left: data black, model green. Right: full res models used broken into components <LINK> The reconstructed stellar flux results in 11 possible scenarios for the area occulted by the planet as it transits the star. We are able to rule out 8/11 based on the geometry and the planet #TRAPPIST1 #paper <LINK> We are further able to use planetary models to rule out the 2Tc+m scenario. Because, while models fit in the wavelengths we measured with @NASAHubble if you include @NASAspitzer this one breaks down #TRAPPIST1 <LINK> This leaves the final scenarios 2T and 3T which result in the same transmission spectrum for the planet, where no stellar flux is contaminating it, as the remaining most probable result where 3T is the favored scenario for the star #TRAPPIST1 <LINK> The series of steps we take in the case study on #TRAPPIST1g can be applied to any star planet combination, but is most effective for late type M stars where stellar molecular features will mimic the planet signals. In each of the steps we detail the important procedures to use to make sure that units are correctly calculated and that each assumption is explored in relation to the data available. and finally I will say this work would not have been possible without my coauthors especially @NikoleKLewis, @Onoastrmer @Of_FallingStars, @NatashaBatalha, Giovanni Bruno, Jules Fowler, and Jeff Valenti who joined me in the #TRAPPISTbunker It also makes for a very pretty title slide #TRAPPIST1g #scicomm <LINK>",https://arxiv.org/abs/1811.04877,"The atmospheres of late M stars represent a significant challenge in the characterization of any transiting exoplanets due to the presence of strong molecular features in the stellar atmosphere. TRAPPIST-1 is an ultra-cool dwarf, host to seven transiting planets, and contains its own molecular signatures which can potentially be imprinted on planetary transit lightcurves due to inhomogeneities in the occulted stellar photosphere. We present a case study on TRAPPIST-1g, the largest planet in the system, using a new observation together with previous data, to disentangle the atmospheric transmission of the planet from that of the star. We use the out-of-transit stellar spectra to reconstruct the stellar flux based on one-, two-, and three-temperature components. We find that TRAPPIST-1 is a 0.08 M$_*$, 0.117 R$_*$, M8V star with a photospheric effective temperature of 2400 K, with ~35% 3000 K spot coverage and a very small fraction, <3%, of ~5800 K hot spot. We calculate a planetary radius for TRAPPIST-1g to be Rp = 1.124 R$_\oplus$ with a planetary density of $\rho_p$ = 0.8214 $\rho_\oplus$. Based on the stellar reconstruction there are eleven plausible scenarios for the combined stellar photosphere and planet transit geometry; in our analysis we are able to rule out 8 of the 11 scenarios. Using planetary models we evaluate the remaining scenarios with respect to the transmission spectrum of TRAPPIST-1g. We conclude that the planetary transmission spectrum is likely not contaminated by any stellar spectral features, and are able to rule out a clear solar H2/He-dominated atmosphere at greater than 3-sigma. ","Disentangling the planet from the star in late type M dwarfs: A case