In regards to their appearance, Meyer-group comets all share a very common morphology. Nearly all Meyer-group comets are very condensed in appearance, although generally slightly elongated as seen in SOHO/LASCO C2. Their condensed appearance suggests that they are relatively “inactive” in nature (Battams and Knight, 2015). A composite image of various “typical” Meyer-group members is shown in Figure 1. Indeed, other than their varying brightness, their morphologies are strikingly similar. For comparison, Kreutz-group comets are generally somewhat fuzzy, (although highly condensed members have been observed, e.g. SOHO-3847). Marsden and Kracht comets also tend display “stellar” morphologies. Unlike the Kreutz, Marsden, Kracht-I and Kracht-II groups, that appear to be dynamically evolving, the Meyer-group is most likely a highly evolved comet family (Lamy et al., 2013; Battams and Knight, 2015). Indeed, Battams and Knight (2015) suggest that the precursor of the Meyer-group may potential have first fragmented as long as ~10.000 years ago. Moreover, unlike the latter comet groups, Meyer comets rarely arrive in tight clusters. However, there have been exceptions: on November 4-5th, 2019, a group of three Meyer-group comets were seen over a span of only eight hours (Figure 2). Note that, in average, one Meyer-group comet is observed per month. This is the “tightest” known Meyer-group cluster discovered to date.
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