# # Program information file # PROGRAM_ID 2023B083 PROGRAM_TITLE Observing variability in the ro-vibrational CO emission of the Herbig Ae star system AB Aur PROGRAM_INV1 Janus Kozdon PROGRAM_INV2 Sean Brittain PROGRAM_INV3 Josh Kern PROGRAM_INV4 Stanley Jensen PROGRAM_INV5 Andrea Banzatti PROGRAM_SCICAT extra-solar planets PROGRAM_ABSTRACT_BEG Long term monitoring of protoplanetary disks using high resolution spectroscopy has been shown to provide evidence of forming planets. Earlier iSHELL observations of AB Aurigae and its transition disk present the case for asymmetric CO ro-vibrational emission lines originating from the inner tens of AU of the disk. With the recent discovery of a protoplanet candidate located at 93 AU, we propose to reobserve AB Aurigae with iSHELL and obtain a SNR per pixel ~300 in order to characterize the asymmetry in the CO ro-vibrational emission and determine the source. Whether it is a CPD or an azimuthally extended structure such as a vortex. We will observe the system along 2 PAS [planet axis and orthogonal axis] in order to make spectro-astrometric measurements to localize the asymmetric source. With a SNR per pixel ~300, our fidelity in the spectro-astrometric measurement will be ~1 mas. Including a dilution factor of 3%, a forming planet at 93 AU would manifest a spatial offset of ~17.1 mas which we will be measurable. This spectro-astrometric signal can be used to confirm whether this protoplanet candidate is the source of the signal or an azimuthally extended structure present in AB Aurigae's inner disk. PROGRAM_ABSTRACT_END