Science Highlight: ALMA imaging of the M-dwarf Fomalhaut C’s debris disc
A new article led by Patrick Cronin-Coltsmann (University of Warwick) and published in Monthly Notices reports on imaging the debris disc around the M-dwarf Fomalhaut C with ALMA (see image above). The authors summarise their paper in the following:
"Debris discs, which are the next stage in evolution after protoplanetary discs, are circumstellar rings comprised of planetesimals and the dust they produce in their collisions. Surveys have been able to detect debris discs around ~20% of Sun-like main sequence stars. However, detections of discs around low-luminosity hosts remain scarce, possibly due to relatively poor illumination and heating but also perhaps because of differences in planet and planetesimal formation.
We have returned to the nearby and famous Fomalhaut triple star system with the hope of finally uncovering the secrets of its history. The spectacular debris disc of the A-type Fomalhaut A has already been imaged with ALMA, and now we've also imaged the debris disc around its far-flung companion, Fomalhaut C, resolving the disc for the first time. In our paper we review previous theories of the triple system's dynamical past and scour the disc for the imprints of these past stellar interactions. However, Fomalhaut C and its disc have their own unique merits too.
As an M4V star, Fomalhaut C is the latest-type star to have a resolved debris disc. The addition of Fomalhaut C to the current sample of resolved discs significantly extends the parameter space by over an order of magnitude in host-star luminosity and finds excellent consistency with previously posited host luminosity - disc radius trends. However, the ratio of the dust temperature to the temperature of an ideal blackbody at the radius of the disc diverges from the trend. This could be because of the extreme low luminosity of the host. Since radiation pressure is too weak to remove even the smallest dust grains from the system, stellar winds become the dominant grain removal mechanism, possibly leading to a different mix of dust grain sizes and properties.
This unique regime is underexplored because of our dearth of detections, so our understanding of these elusive systems and their planet-formation history will grow by leaps and bounds as ALMA images more M-type discs."
Upcoming I-TRAIN events from the EU ARC
Note: In both cases, the tutors' presentation will be recorded, and an edited version of the recording will be posted in the Science Portal after the session. The interactive Q&A will not be recorded.
I-TRAIN #6: Improving image fidelity through self-calibration
25 May 2021, 11:00 CEST (10:00 BST)
In this session, you will learn how to self-calibrate your interferometric images to improve their image fidelity. In particular, you will learn criteria for deciding whether to self-calibrate, how to choose parameter values, and when to stop, and thus how to improve the image dynamic range and bring faint details out of the noise.
To be able to follow this tutorial in full, attendees will be asked to do some preparation work before the session. These preparations consist of downloading a dataset and installing a compatible CASA version, and instructions on how to do so will be made available on the Science Portal at least a week in advance. Presentation slides will be made available in the Science Portal the day before the session.
I-TRAIN #7: Polarization observations with ALMA
24 June 2021, 11:00 CEST (10:00 BST)
The European ARC Network invites users to an online training session on polarization observations with ALMA in which participants will learn about ALMA’s polarization capabilities and the data products available in the archive. In particular, instructions on how to inspect the diagnostic information on data calibration and how to produce polarization images will be given.
Astrochemistry Group Meeting 2021: Astrochemistry in the JWST era
16 - 18 June 2021
The Astrochemistry Group invites you to the 2021 annual meeting, to be held virtually and hosted by the University of Leeds. The meeting, on the topic of “Astrochemistry in the JWST era” will include the annual general meeting (AGM) of the Astrochemistry Group on 17th June 2021. We welcome all contributions on the theme of astrochemistry including observations, modelling, experiments, and instrumentation. There are 12 contributed talk slots available over the course of the meeting and abstract submission is due by 1st June 2021. The meeting sessions are scheduled daily from 1pm to 4pm BST (UTC+1) to facilitate international participation.
In this joint RSC/RAS meeting, and as a look forward to the launch of JWST, talks will include contributions from invited speakers with expertise in JWST observations and instrumentation, laboratory experiments on solid-state infrared spectroscopy, and computational models of molecular spectra at infrared wavelengths.
For further information please contact the meeting organiser Catherine Walsh via the meetings webpage.