ALMA and Keck analysis of Fomalhaut field sources: JWST's Great Dust Cloud is a background object

Abstract

At 7.7 pc, the A-type star Fomalhaut hosts a bright debris disk with multiple radial components. The disk is eccentric and misaligned, strongly suggesting that it is sculpted by interaction with one or more planets. Compact sources are now being detected with JWST, suggesting that new planet detections may be imminent. However, to confirm such sources as companions, common proper motion with the star must be established, as with unprecedented sensitivity comes a high probability that planet candidates are actually background objects. Here, ALMA and Keck observations of Fomalhaut are found to show significant emission at the same sky location as multiple compact sources in JWST MIRI coronagraphic observations, one of which has been dubbed the "Great Dust Cloud" because it lies within the outer belt. Since the ground-based data were obtained between 6 to 18 years prior to the JWST observations, these compact sources are unlikely to be common proper motion companions to Fomalhaut. More generally, this work illustrates that images collected at a range of wavelengths can be valuable for rejecting planet candidates uncovered via direct imaging with JWST.

MNRAS in press

References in corpus (12)

• The James Webb Space Telescope
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets
• Detection of exocometary CO within the 440 Myr-old Fomalhaut belt: a similar CO+CO${}_2$ ice abundance in exocomets and Solar System comets
• Herschel images of Fomalhaut. An extrasolar Kuiper Belt at the height of its dynamical activity
• A Complete ALMA Map of the Fomalhaut Debris Disk
• The ALMA Spectroscopic Survey in the HUDF: Deep 1.2 mm continuum number counts
• Spatially resolved imaging of the inner Fomalhaut disk using JWST/MIRI
• High resolution ALMA and HST images of q${}^1$ Eri: an asymmetric debris disc with an eccentric Jupiter
• The unexpected narrowness of eccentric debris rings: a sign of eccentricity during the protoplanetary disc phase
• Source counts at 7.7 to 21 $\mu$m in CEERS field with James Webb Space Telescope
• High resolution ALMA and HST imaging of $\kappa$CrB: a broad debris disc around a post-main sequence star with low-mass companions

Cited by in corpus (4)

• The ALMA survey to Resolve exoKuiper belt Substructures (ARKS): VI. Asymmetries and offsets
• ALMA Reveals an Eccentricity Gradient in the Fomalhaut Debris Disk
• Searching for Planets Orbiting Vega with the James Webb Space Telescope
• High Resolution ALMA Data of the Fomalhaut Debris Disk Confirms Apsidal Width Variation