Deep exploration of the planets HR 8799 b, c, and d with moderate resolution spectroscopy

Understand

The four directly imaged planets orbiting the star HR 8799 are an ideal laboratory to probe atmospheric physics and formation models.

• We present more than a decade's worth of Keck/OSIRIS observations of these planets, which represent the most detailed look at their atmospheres to-date by its resolution and signal to noise ratio.
• We present the first direct detection of HR 8799 d, the second-closest known planet to the star, at moderate spectral resolution with Keck/OSIRIS (K-band; R~4,000).
• Additionally, we uniformly analyze new and archival OSIRIS data (H and K band) of HR 8799 b, c, and d.