Identify the Nature of the Extended Secondary-Disk Feature

Determine whether the low-signal feature extending beyond the outer dust halo of the β Pictoris debris disk is the scattered-light counterpart of the extended secondary disk detected with JWST/MIRI or an artifact produced by point-spread-function subtraction.

Background

The HST/STIS observations reveal a low signal-to-noise feature below the northeastern midplane that appears to extend beyond the visible dust halo. Its location is close to that of the extended secondary disk previously observed in JWST/MIRI imaging, but the MIRI field of view does not cover the region beyond the STIS-observed halo. Consequently, the spatial relationship between the two features cannot currently be established.

The feature may also be a point-spread-function artifact, particularly because of its low signal-to-noise ratio and its apparent orientation toward the central star. The authors indicate that deeper observations of the outer β Pictoris disk could resolve this ambiguity.

References

Since the field of view of the MIRI observations does not extend past the halo observed with STIS, it is difficult to determine whether the signal seen with STIS is offset from the extended secondary disk or whether the extended secondary disk would be coincident with the feature seen with STIS (see Figure \ref{fig:rgb}). The low SNR nature of the signal and the fact that the structure may point at the central star makes it so that we cannot rule out that the observed structure is a PSF artifact.

— Deep HST/STIS Coronagraphic Imaging of the $β$ Pictoris Debris Disk: On the Scattered Light Component of the Cat's Tail  (2609.30111 - Avsar et al., 24 Sep 2026) in Section 3.2, “Potential Low SNR Detection of Extended Secondary Disk in STIS Observations”