A Multiwavelength Study of 1WGA J1346.5−6255: A New γ Cas Analog Unrelated to the Background Supernova Remnant G309.2−00.6

1WGA J1346.5-6255 is a ROSAT X-ray source found within the radio lobes of thesupernova remnant (SNR) G309.2-00.6. This source also appears to coincide withthe bright and early-type star HD 119682, which is in the middle of thegalactic open cluster NGC 5281. The radio morphology of the remnant, consistingof two brightened and distorted arcs of emission on opposite sides of the 1WGAJ1346.5-6255 source and of a jet-like feature and break in the shell, led tothe suggestion that 1WGA J1346.5-6255/G309.2-00.6 is a young analog of themicroquasar SS 433 powering the W50 nebula. This motivated us to study thissource at X-ray and optical wavelengths. We here present new Chandraobservations of 1WGA J1346.5-6255, archival XMM-Newton observations ofG309.2-00.6, and optical spectroscopic observations of HD 119682, in order tosearch for X-ray jets from 1WGA J1346.5-6255, study its association with theSNR, and test for whether HD 119682 represents its optical counterpart. We donot find evidence for jets from 1WGA J1346.5-6255 down to an unabsorbed flux of2.6E-13 ergs/cm2/s (0.5-7.5 keV), we rule out its association with G309.2-00.6,and we confirm that HD 119682 is its optical counterpart. We derive a distanceof 1.2+/-0.3 kpc, which is consistent with the distance estimate to NGC 5281(1.3+/-0.3 kpc), and much smaller than the distance derived to the SNRG309.2-00.6. We discuss the nature of the source, unveil that HD 119682 is a Bestar and suggest it is a new member of the recently proposed group of$\gamma$-Cas analogs. The Chandra and XMM X-ray lightcurves show variability ontimescales of hundreds of seconds, and the presence of a possible period ofabout 1500 s that could be the rotational period of an accreting neutron staror white dwarf in this $\gamma$-Cas analog.