The proper motion of HV2112: A T\.ZO candidate in the SMC

Abstract

The candidate Thorne-\.Zytkow object (T\.ZO), HV2112, is becoming a well-studied if enigmatic object. A key point of its candidacy as a T\.ZO is whether or not it resides in the Small Magellanic Cloud (SMC). HV2112 has detections in a series of photometric catalogues which have resulted in contradictory estimates of its proper motion and, therefore, its membership within the SMC. This letter seeks to resolve the issue of the SMC membership of HV2112 through a reanalysis of extant photometric data. We also demonstrate the difficulties and downfalls inherent in considering a range of catalogue proper motions. We conclude that the proper motion, and associated ancillary radial velocity, positional and photometric properties, are fully consistent with HV2112 being within the SMC and thus it remains a candidate T\.ZO.