Daniel Jontof-Hutter - Precise Planetary Masses, Radii and Orbital Eccentricities of Sub-Neptunes from Transit Timing - ERESS 2015 Presented at the Emerging Researchers in Exoplanet Science Symposium 2015 on Thursday, May 28th, 2015. For more information and talk videos visit http://eres-symposium.org/. Kepler’s bounty of sub-Neptunes enables us to study a regime in planetary size and mass that includes a transition from rocky planets to those with substantial envelopes of volatiles— either ices or gases. Characterizing these planets’ masses and radii can probe this transition.There is a small sample of exoplanets with known masses and radii, mostly hot Jupiters whose radii are known from transit depths, and whose masses are determined from radial velocity spectroscopy (RV). In the absence of detectable RV, observed transit timing variations (TTVs) probe perturbations between planets that pass close to one another or are near resonance, and hence dynamical fits can measure planetary masses and eccentricities, particularly in compact multi-planet systems.The precision in measuring the radius of a transiting planet rests on the uncertainty in the stellar radius, typically ~10% for targets with spectral follow-up. With TTVs, however, solutions for the orbital eccentricity can, alongside spectra and the transit light curve, tightly constrain the stellar density and radius, permitting useful planetary density determinations. Here we show the wide range of sizes in planets with measured masses from 5-10 Earth masses; from super-earth size and likely rocky, to sub-saturn size with volumes dominated by light gases.

• published: 11 Jun 2015
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