Direct spectroscopy of an exoplanet with the JWST/NIRSpec IFU

Program lead: Stephan Birkmann

Collaboration with other GTO teams: this program is conducted in collaboration with the MIRI EC GTO team.

Program duration: 6 hours

Thanks to instruments like GPI (Gemini Planet Imager) and SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research), we now have a small list of exoplanets with wide orbital separations that are suitable for direct imaging or spectroscopy with JWST. Direct spectroscopy provides complementary information on the physics of a category exoplanets that cannot be probed by transit observations. It may reveal the properties of the planetary surface, its temperature profile and chemical composition. This program aims at obtaining direct spectroscopy of one of these exoplanets with the NIRSpec IFU in combination with the MIRI IFU (as part of the MIRI European Consortium GTO program). This target will be young and massive enough so that internal heat yields thermal emission detectable by NIRSpec at 5 μm (T > 500 K). One interesting science goal will be to test the cloud/out-of-equilibrium physics in this object, in particular in the context of the giant planet versus brown dwarf formation scenarios. Note that if these potentially challenging observations are obtained early, this program will be a good demonstration of the capabilities of the NIRSpec IFU for the spectroscopic studies of faint targets located at several tenths of an arcsecond from a bright point source (~0.8-1 arcsecond).

Observations and targets :

TWA 27 (2M1207)


Spatially dithered IFU observations using the G140H/F100LP, G235H/F170LP, and G395H/F290LP configurations, providing 1.0 to 5.2 micron wavelength coverage with high (~2700) spectral resolution. Total on-source exposure times are approximately 1900 seconds per configuration.

TWA 28(reference star)


Identical observation of a nearby isolated star of a similar brightness and spectral type as the exoplanet host star.