  The discovery of the transient Jupiter co-orbital comet P/2019 LD2 (ATLAS)
drew significant interest. Not only will LD2 transition between being a Centaur
and a Jupiter Family Comet (JFC) in 2063, the first time this process can be
observed as it happens, it is also very active for its large heliocentric
distance. We present observations and orbital integrations of the newly
discovered transient Jupiter co-orbital comet P/2023 V6 (PANSTARRS), the second
such object known. Despite similar modern orbits, V6 is significantly (15
times) less active than LD2 and most JFCs as determined via Afrho measurements
at the same heliocentric distance. We find V6 is co-orbital between 2020 and
2044, twice the duration of LD2, but it will not become a JFC soon. We
interpret these differences in activity as evolutionary, with V6 having lost a
significant fraction of its near-surface ice compared to LD2 by previously
being warmer. While V6's pre-encounter orbit was somewhat warmer than LD2's,
future thermal modeling will be needed to understand if this can explain their
differences or if a more significant difference further into the past is
required. This is more evidence that LD2 is a pristine and ice-rich object, and
thus it may display very strong activity when it becomes a JFC. We sue the
differences between V6 and LD2 to discuss the interpretation of cometary
activity at large heliocentric distances as well as the small end of the crater
record of the Galilean Satellites. Continuing observations of both objects are
highly encouraged.
