ALMA and NACO observations towards V1400 Cen

Our aim was to directly detect the thermal emission of the putative exoring system responsible for the complex deep transits observed in the light curve for the young Sco-Cen star 1SWASP J140747.93-394542.6 (V1400 Cen, hereafter J1407), confirming it as the occulter seen in May 2007, and to determine its orbital parameters with respect to the star. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the field centred on J1407 in the 340GHz (Band 7) continuum in order to determine the flux and astrometric location of the ring system relative to the star.

We used the VLT/NACO camera to observe the J1407 system in March 2019 and to search for the central planetary mass object at thermal infrared wavelengths. We detect no point source at the expected location of J1407, and derive an upper limit 3{sigma} level of 57.6uJy. There is a point source detected at an angular separation consistent with the expected location for a free-floating ring system that occulted J1407 in May 2007, with a flux of 89uJy consistent with optically thin dust surrounding a massive substellar companion.