Resolved gas cavities in transitional disks inferred from CO isotopologs with ALMA

By N. Marel, E. Dishoeck, Simon Bruderer, S. Andrews, K. Pontoppidan, G. Herczeg, T. V. Kempen, A. M. L. Observatory, The Netherlands., Max-Planck-Institut fur extraterrestrische Physik and 7 more. 2015

165 citations recorded by the source corpus.

Transitional disks around young stars are promising candidates to look for recently formed, embedded planets. Planet-disk interaction models predict that planets clear a gap in the gas while trapping dust at larger radii. Other physical mechanisms could be responsible for cavities as well. Previous observations have revealed that gas is still present inside these cavities, but the spatial distribution of this gas remains uncertain. We present high spatial resolution observations with the Atacama Large Millimeter/submillimeter Array (ALMA) of 13CO and C18O lines of four well-studied transitional disks. The observations are used to set constraints on the gas surface density, specifically cavity size and density drop inside the cavity. The physical-chemical model DALI is used to analyze the gas images of SR21, HD135344B, DoAr44 and IRS48. The main parameters of interest are the size, depth and shape of the gas cavity. CO isotope-selective photodissociation is included to properly constrain the surface density in the outer disk from C18O emission. The gas cavities are up to 3 times smaller than those of the dust in all four disks. Model fits indicate that the surface density inside the gas cavities decreases by a factor of 100-10000 compared with the surface density profile derived from the outer disk. A comparison with an analytical model of gap depths by planet-disk interaction shows that the disk viscosities are likely low, with a<1E-3 for planet masses <10 MJup. The resolved measurements of the gas and dust in transition disk cavities support the predictions of models that describe how planet-disk interactions sculpt gas disk structures and influence the evolution of dust grains. These observed structures strongly suggest the presence of giant planetary companions in transition disk cavities, although at smaller orbital radii than is typically indicated from the dust cavity radii alone.

Subfields: Astronomy and Astrophysics, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/f9ef0d35029c366b7aeadc1162f08aa2dad5dda5

How researchers see this paper

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In Astronomy and Astrophysics

1. S. Andrews
2. Jonathan P. Williams
3. G. Herczeg
4. L. Testi
5. L. Hartmann
6. A. Natta
7. D. Wilner
8. N. Calvet

In Spectroscopy

1. Jonathan P. Williams
2. L. Hartmann
3. G. Herczeg
4. N. Calvet
5. L. Testi
6. A. Natta
7. S. Andrews
8. K. Luhman

Citations in the corpus

• Accretion onto Pre-Main-Sequence Stars (2016, background): “Recent high-resolution Atacama Large Millimeter Array (ALMA) studies have suggested that the gas interior to the dusty region is depleted (van der Marel et al. 2015) by at least an order of magnitude, and in some cases by factors of more than 102–104 (van der Marel et al. 2016); however, such…”
• ALMA SURVEY OF LUPUS PROTOPLANETARY DISKS. I. DUST AND GAS MASSES (2016, background): “…were identified as TD candidates in the literature, but do not exhibit cavities in our ALMA images: Sz 84 (Meŕın et al. 2010), MY Lup 9 (Romero et al. 2012), Sz 112, 2MASS J160115494152351 (van der Marel et al. 2016b), 2MASS J161029553922144, and 2MASS J16081497-3857145 (Bustamante et al. 2015).”