SOFIA observations with the GREAT receiver provide spectrally resolved (~0.2 km/s) observations of [OI] at 63 μm and OH at 163 μm, towards three proplyds in Orion: HST 10, 244-440 and the Beehive. These three proplyds in Orion have also been observed with Herschel covering multiple lines: [CII], several high-J CO lines and spectrally unresolved [OI] emission ( Champion et al. 2017 ). This provides valuable complementary data to constrain the heated gas in these proplyds with PDR and shock models.
The spectral resolution of the SOFIA [OI] observations e.g. allows to separate the disk and jet in the proplyds. OH likely originates from dense irradiated regions. The first detection of OH at 84 μm in Herschel data towards one of the proplyds was presented in Parikka et al. 2017 . The spectral resolution offered by SOFIA will allow to better understand the origin of this OH emission and so constrain shock and PDR models in proplyds. All the SOFIA data for the proplyds can be found in the SOFIA science archive under program ID 03_0138 . This program also covers the large Carina proplyd at 2.3 kpc in [OI] and CO(16-15) which provides an additional target to investigate.
(Left) HST Hα image of the 244-440 proplyd in Orion (adapted from Champion et al. 2017). (Right) The GREAT spectra of OH and [OI] towards the 244-440 proplyd.