Spectroscopy of HR 8799 planets with SCExAO/CHARIS

We present two full nights of coronagraphic observations of the HR8799 planets using the CHARIS integral field spectrograph behind the SCExAO adaptive optics system on the Subaru Telescope to search for spectrophotometric variability. We did not detect significant variability signals, but placed the lowest variability upper limits for HR 8799c and d.

Based on injection-recovery tests, we expected to have a 50% chance to detect signals down to 10% H-band photometric variability for HR 8799c and down to 30% H-band variability for HR8799d. We also investigated spectral variability and expected a 50% chance to recover 20% variability in the H/K flux ratio for HR8799c. We combined all the data from the two nights to obtain some of the most precise spectra obtained for HR8799c, d, and e.