2024RNAAS...8...64K

Outbursts from young Class 0 protostars are now being detected using 3-5 μm light curves assembled from Spitzer and WISE/NEOWISE photometry. For comparison, we present a 4-8 μm light curve of the erupting, more evolved protostar V1647 Ori (HOPS 388), assembled from photometry obtained with the ISOCAM camera on ISO, the IRAC camera on Spitzer, and from WISE and NEOWISE. Covering 26 yr, this light curve spans the longest available time interval from infrared space-based telescopes capable of separating individual young stellar objects in nearby molecular clouds. This curve does not include a two year interval where the visible-light photometry shows a large drop in brightness. In the case of V1647 Ori, we find that the increase in brightness (3.1 mag) and duration (16 yr) are similar to infrared (3-5 μm) outbursts found toward Class 0 protostars in Orion.