ALMA imaging of the M-dwarf Fomalhaut C's debris disc

Abstract

Fomalhaut C (LP 876-10) is a low mass M4V star in the intriguing Fomalhaut triple system and, like Fomalhaut A, possesses a debris disc. It is one of very few nearby M-dwarfs known to host a debris disc and of these has by far the lowest stellar mass. We present new resolved observations of the debris disc around Fomalhaut C with the Atacama Large Millimetre Array which allow us to model its properties and investigate the system's unique history. The ring has a radius of 26 au and a narrow full width at half maximum of at most 4.2 au. We find a 3$\sigma$ upper limit on the eccentricity of 0.14, neither confirming nor ruling out previous dynamic interactions with Fomalhaut A that could have affected Fomalhaut C's disc. We detect no ${}^{12}$CO J=3-2 emission in the system and do not detect the disc in scattered light with HST/STIS or VLT/SPHERE. We find the original Herschel detection to be consistent with our ALMA model's radial size. We place the disc in the context of the wider debris disc population and find that its radius is as expected from previous disc radius-host luminosity trends. Higher signal-to-noise observations of the system would be required to further constrain the disc properties and provide further insight to the history of the Fomalhaut triple system as a whole.

15 pages, 10 figures, 2 tables, Accepted for publication in MNRAS

References in corpus (32)

• The Gaia mission
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• A stellar-mass-dependent drop in planet occurrence rates
• "TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations
• ALMA spectroscopic survey in the Hubble Ultra Deep Field: Continuum number counts, resolved 1.2-mm extragalactic background, and properties of the faintest dusty star forming galaxies
• Resolved Debris Discs Around A Stars in the Herschel DEBRIS Survey
• 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
• Disk Radii and Grain Sizes in Herschel-Resolved Debris Disks
• A Complete ALMA Map of the Fomalhaut Debris Disk
• "TNOs are Cool": A survey of the trans-Neptunian region VI. Herschel/PACS observations and thermal modeling of 19 classical Kuiper belt objects
• CO mass upper limits in the Fomalhaut ring - the importance of NLTE excitation in debris discs and future prospects with ALMA
• Collisional and Thermal Emission Models of Debris Disks: Towards Planetesimal Population Properties
• The Northern Arc of $\epsilon$ Eridani's Debris Ring as Seen by ALMA
• ALMA observations of the narrow HR 4796A debris ring
• Formation of Narrow Dust Rings in Circumstellar Debris Disks
• Investigating the flyby scenario for the HD 141569 system
• The SHARDDS survey: first resolved image of the HD114082 debris disk in Lower Centaurus Crux with SPHERE
• A statistically significant lack of debris discs in medium separation binary systems
• New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
• On the Ubiquity and Stellar Luminosity Dependence of Exocometary CO Gas: Detection around M Dwarf TWA 7
• First scattered-light images of the gas-rich debris disk around 49 Ceti
• Fomalhaut b as a Dust Cloud: Frequent Collisions within the Fomalhaut Disk
• Fomalhaut b as a Cloud of Dust: Testing Aspects of Planet Formation Theory
• A Near-coplanar Stellar Flyby of the Planet Host Star HD 106906
• No significant correlation between radial velocity planet presence and debris disc properties
• Dancing with the Stars: Formation of the Fomalhaut triple system and its effect on the debris disks
• Insights on the dynamical history of the Fomalhaut system - Investigating the Fom c hypothesis
• Deep Herschel PACS point spread functions
• Simulations of the Fomalhaut System Within Its Local Galactic Environment
• Constraints on the gas content of the Fomalhaut debris belt. Can gas-dust interactions explain the belt's morphology?
• Understanding Fomalhaut as a Cooper pair

Cited by in corpus (6)

• Planet populations inferred from debris discs: insights from 178 debris systems in the ISPY, LEECH and LIStEN planet-hunting surveys
• Characterizing the morphology of the debris disk around the low-mass star GSC~07396-00759
• Stirred but not shaken: a multi-wavelength view of HD 16743's debris disc
• The SHARDDS survey: limits on planet occurrence rates based on point sources analysis via the Auto-RSM framework
• ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin
• vis-r: Quick radial profile modelling for radio interferometric visibilities