High resolution observations of molecular emission lines toward the CI Tau proto-planetary disc: planet-carved gaps or shadowing?

Year: 2020

Type: article

Abstract: Recent observations have revealed that most proto-planetary discs show a pattern of bright rings and dark gaps. However, most of the high-resolution observations have focused only on the continuum emission. In this Paper we present high-resolution ALMA band 7 (0.89mm) observations of the disc around the star CI Tau in the 12CO & 13CO J = 3–2 and CS J = 7–6 emission lines. Our recent work demonstrated that the disc around CI Tau contains three gaps and rings in continuum emission, and we look for their counterparts in the gas emission. While we find no counterpart of the third gap and ring in 13CO, the disc has a gap in emission at the location of the second continuum ring (rather than gap). We demonstrate that this is mostly an artefact of the continuum subtraction, although a residual gap still remains after accounting for this effect. Through radiative transfer modelling we propose this is due to the inner disc shadowing the outer parts of the disc and making them colder. This raises a note of caution in mapping high-resolution gas emission lines observations to the gas surface density – while possible, this needs to be done carefully. In contrast to 13CO, CS emission shows instead a ring morphology, most likely due to chemical effects. Finally, we note that 12CO is heavily absorbed by the foreground preventing any morphological study using this line.

Source: Monthly Notices of the Royal Astronomical Society

DOI: 10.1093/mnras/staa3869

Authors: Giovanni P Rosotti, John D Ilee, Stefano Facchini, Marco Tazzari, Richard A Booth, Cathie Clarke, Mihkel Kama

Institutions: Leiden University, Leiden Observatory, University of Leeds, European Southern Observatory, University of Cambridge, Tartu Observatory, University College London, University of Tartu

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: bronze

Funders: National Science Foundation, National Radio Astronomy Observatory, European Commission, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, Tartu Ülikool, Science and Technology Facilities Council, National Institutes of Natural Sciences, European Regional Development Fund

OpenAlex ID: W3113230397