Dynamically new comet C/2025 D1 (Groeller) with record perihelion distance
R. Weryk, Sam Deen, D. J. Tholen, Marco Micheli et autres
We studied C/2025 D1 (Groeller), a long-period comet with an unprecedented perihelion distance of 14.1 au, using archival observations. The data reveal that it had been active at inbound heliocentric distances rH ≳ 20 au. Initially, the comet intrinsically brightened at rH …