Possible stratospheric emission in the warm Neptune GJ 436 b from high-resolution spectroscopy

Luke Finnerty, Michael P Fitzgerald, Jerry W Xuan +26

We present high spectral resolution $L$ band (2.91--3.85 $\hat{I}¼$m) observations of the warm Neptune GJ 436 b from Keck II/KPIC. KPIC's single-mode fiber feed reduces the $L$ band sky…