Investigating point sources in MWC 758 with SPHERE

TL;DR

This study used VLT/SPHERE to search for planetary candidates in MWC 758 but did not confirm previous detections, suggesting the need for deeper, longer observations to identify the spiral arms' source.

Contribution

The paper provides a high-contrast imaging analysis that challenges previous L band detections of planetary candidates in MWC 758 and examines the spiral arms' origins.

Findings

Failed to confirm previous L band point source detections

Analysis suggests candidates are unlikely to be the spiral arms' source

Highlights need for deeper, longer-term observations

Abstract

Context. Spiral arms in protoplanetary disks could be shown to be the manifestation of density waves launched by protoplanets and propagating in the gaseous component of the disk. At least two point sources have been identified in the L band in the MWC 758 system as planetary mass object candidates. Aims. We used VLT/SPHERE to search for counterparts of these candidates in the H and K bands, and to characterize the morphology of the spiral arms . Methods. The data were processed with now-standard techniques in high-contrast imaging to determine the limits of detection, and to compare them to the luminosity derived from L band observations. Results. In considering the evolutionary, atmospheric, and opacity models we were not able to confirm the two former detections of point sources performed in the L band. In addition, the analysis of the spiral arms from a dynamical point of view does not support the hypothesis that these candidates comprise the origin of the spirals. Conclusions. Deeper observations and longer timescales will be required to identify the actual source of the spiral arms in MWC 758.