What you don't see...: exoplanet transit studies

Ground-based and space-based observatories have made great progress in the study of planets around nearby stars. Radial velocity measurements from Keck and other high resolution spectrographic facilities have identified multiple systems and characterized the distribution of ellipticities. Dedicated survey telescopes continue to search for nearby transiting systems. For transiting systems, astronomers have used Hubble and Spitzer to study the atmospheres of hot Jupiters (very short period systems). The Kepler mission will provide statistics for the frequency of exoplanets with periods of one year or less as well as hundreds of systems with “hot Neptunes” and “superearths”.

The STScI and the JWST SWG have reviewed Webb’s capabilities for enabling imaging and spectroscopic studies of transiting exoplanets. These studies show that by using fast readout methods, Webb should be capable of high signal to noise ( S/N ~ 10,000-100,000) observations of both planetary transits and occultations. While unknown systematic effects may ultimately limit the achievable signal to noise, we will strive to maintain the data rates, readout modes and subarray sizes needed to observe bright (KAB ~ 6) transiting systems without saturating the NIR and MIR detectors.

Relevant studies:

JWST-STScI-001601- NIRSpec Subarrays for Planetary Transits and Other Bright Targets
JWST-STScI-001757- MIRI Subarrays for Planetary Transits and Other Bright Targets
JWST-STScI-001767- Transit Observations with NIRCam: Subarrays, Data Volumes and Readout Modes
Clampin et al. 2009- Comparative Planetology: Transiting Exoplanet Science with JWST

Updated: October 2009