Abstract

A Large Hubble Space Telescope Survey of Low-Mass Exoplanets

Björn Benneke (Caltech)

Ian Crossfield(2); Heather Knutson(1); Joshua Lothringer(2); Peter McCullough(4); Diana Dragomir(3); Caroline Morley(5); Eliza Kempton(6); Andrew Howard (1); Jonathan Fortney (5) 1. Caltech 2. University of Arizona 3. University of Chicago 4. University of Maryland 5. UC Santa Cruz 6. Grinell College

The discovery of short-period planets with masses and radii between Earth and Neptune was one of the biggest surprises in the brief history of exoplanet science. From the Kepler mission, we know that these “super-Earths” or “sub-Neptunes” orbit at least 40% of stars, likely representing the most common outcome of planet formation. Despite this ubiquity, we know little about their typical compositions and formation histories. In this talk, we will shed new light on these worlds by presenting new results from our 124-orbit HST transit spectroscopy survey to probe the chemical compositions of low-mass exoplanets. We will report on multiple molecular detections. Our unprecedented HST survey provides the first comprehensive look at this intriguing new class of planets by covering seven planets ranging from 1 Neptune mass and temperatures close to 2000K to a 1 Earth-mass planet near the habitable zone of its host star.

Talk