Detection of the 2021 Arid Meteor Shower on Maunakea, Hawai'i
We report the successful detection of the "Arid" Meteor Shower (IAU\#1130 ARD), predicted to emerge for the first time in 2021, using a publicly accessible YouTube live camera developed by us. This live camera, installed on the Subaru Telescope dome in the summit region of Maunakea, Hawai'i, features a wide field of view (70 deg by 40 deg) and high sensitivity, capable of observing stars fainter than 6th magnitude. Meteor detection was performed in two ways: visual inspection by citizen viewers and subsequent validation through automated detection. As a result, we confirmed that the number of meteors appearing from near the predicted radiant increased by more than six times (~9 sigma) compared to the preceding and following days. Our observation time was 4-5 hours after the predicted peak (solar longitude = 193.9 deg), providing clear data indicating that the activity had not yet declined. Optical observations at this time from the Northern Hemisphere are extremely limited and unique, making our observation point valuable. The meteors are characterized as slow and faint appearance, but several brighter meteors with wakes were also observed. Simulations tracing the dust trails from the parent body, Comet 15P/Finlay, suggest that our detection can be explained by either the dust trails released in 2008 or 2014, both requiring high ejection velocities. However, during the comet's 2008 return, its activity was exceptionally quiet, making a high-velocity dust ejection questionable. On the other hand, multiple large outbursts were observed during the 2014 return, at which time a certain amount of high-velocity dust release is expected. We conclude that the dust source of the meteor shower detected in Hawai'i this time is likely attributable to high-velocity (~67 m s-1) dust ejected during the 2014 outburst.