# # Program information file # PROGRAM_ID 2023A084 PROGRAM_TITLE Investigating accretion variability -- disk morphology connection in protoplanetary disks with SpeX/IRTF PROGRAM_INV1 Bihan Banerjee PROGRAM_INV2 Mayank Narang PROGRAM_INV3 Himanshu Tyagi PROGRAM_INV4 Manoj Puravankara PROGRAM_INV5 Prashanta Nayak PROGRAM_SCICAT extra-solar planets PROGRAM_ABSTRACT_BEG ALMA has revealed protoplanetary disks with diverse morphological properties. These diverse morphologies can be connected to different physical conditions and the evolutionary stages. The accretion properties are expected to be closely correlated with the disk physics. However, the nature of such correlations has not been observationally established yet. While there have been multiple independent observations of such disks in near-IR wavelengths, many open questions remain, such as: [1] How does the accretion properties correlate with morphological properties of the disks? [2] Is accretion in a protoplanetary disk intrinsically variable and independent of disk structure? Or do the timescale and amplitude of variability correlate with possible planetary companions or other physical timescales present at the disk? [3] At shorter disk lengths, the timescale of all physical processes is short as well. NIR excess is emitted from the innermost regions of the disk. Therefore studying variation of NIR excess from disks may reveal signs of disk evolution. But what is the typical timescale of variation of NIR excess, and how does it correlate with other disk properties? To answer such questions, we have prepared a well curated sample of ALMA observed protoplanetary disks from Taurus, Ophiuchus and Upper Scorpius regions, consisting of transitional disks [ disks with large inner cavities ], disk with small substructures, and smooth disks with no substructures. We will homogeneously measure their accretion rates and comparing with archival data we will search for signposts of evolution, and characterize the variability of the accretion rates. PROGRAM_ABSTRACT_END