Survival of molecular gas in cavities of transition disks - I. CO

By Simon Bruderer. 2013

154 citations recorded by the source corpus.

(Abridged) Planet formation is closely related to the structure and dispersal of protoplanetary disks. A certain class of disks, called transition disks, exhibit cavities in dust images at scales of up to a few 10s of AU. The formation mechanism of the cavities is still unclear. The gas content of such cavities can be spatially resolved for the first time using the Atacama Large Millimeter/submillimeter Array (ALMA). We have developed a new series of models to simulate the physical conditions and chemical abundances of the gas in cavities to address the question whether the gas is primarily atomic or molecular inside the dust free cavities exposed to intense UV radiation. Molecular/atomic line emission by carbon monoxide (CO), its isotopologues (13CO, C18O, C17O, and 13C18O) and related species ([CI], [CII], and [OI]) is predicted for comparison with ALMA and the Herschel Space Observatory. The gas can remain in molecular form down to very low amounts of gas in the cavity. Shielding of the stellar radiation by a dusty inner disk (pre-transition disk) allows CO to survive down to lower gas masses in the cavity. The main parameter for the CO emission from cavity is the gas mass. Other parameters such as the outer disk mass, bolometric luminosity, shape of the stellar spectrum or PAH abundance are less important. Since the CO pure rotational lines readily become optically thick, the CO isotopologues need to be observed in order to quantitatively determine the amount of gas in the cavity. A wide range of gas masses in the cavity of transition disks (~4 orders of magnitude) can be probed using combined observations of CO isotopologue lines with ALMA. Measuring the gas mass in the cavity will ultimately help to distinguish between different cavity formation theories.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/e8b2cd7688d6f2e6d581c9e2004d3a5989017ed5

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Atomic and Molecular Physics, and Optics

In Instrumentation

Citations in the corpus

Resolved gas cavities in transitional disks inferred from CO isotopologs with ALMA (2015, methodology): “…structure is somewhat higher than in our model, perhaps because of some residual dust in the cavity (increasing the CO abundance by its shielding and changing the heating-cooling balance) or the vertical structure (shadowing on the outer disk; see Bruderer 2013, for a detailed discussion).”
ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet (2017, methodology): “For this purpose we use the dust radiative transfer code implemented into the thermo-chemical disk model DALI (Dust And LInes, Bruderer et al. 2012; Bruderer 2013).”
ALMA Survey of Lupus Protoplanetary Disks. II. Gas Disk Radii (2018, methodology): “…Facchini et al. (2017) combined the dust evolution models from Birnstiel et al. (2015) with the thermo-chemical code DALI (Bruderer et al. 2012; Bruderer 2013) to show that, at least for the case of the massive HD 163296 disk, the bulk of the difference between the gas and dust radii is due to…”
ALMA SURVEY OF LUPUS PROTOPLANETARY DISKS. I. DUST AND GAS MASSES (2016, background): “The larger CO isotopologue detection rate toward the TDs may be explained by the directly heated CO wall increasing the flux of optically thick lines (Bruderer 2013), or could be related to their relatively stronger continuum emission.”
Volatile carbon locking and release in protoplanetary disks. A study of TW Hya and HD 100546 (2016, methodology): “To derive the gas-phase abundance of elemental carbon ([C]/[H]gas), we have run source-specific model grids using the 2D physical-chemical code, DALI (Bruderer et al. 2009, 2012; Bruderer 2013).”
ALMA unveils rings and gaps in the protoplanetary system HD 169142: signatures of two giant protoplanets (2017, methodology): “The simulations presented here were generated using the thermo-chemical disk code dali (Dust and Lines, Bruderer et al. 2012; Bruderer 2013).”
Gas density drops inside dust cavities of transitional disks around young stars observed with ALMA (2015, methodology): “9-10 in Bruderer (2013).”
LARGE-SCALE ASYMMETRIES IN THE TRANSITIONAL DISKS OF SAO 206462 AND SR 21 (2014, unknown): “However, a large depletion of the inner disk (> 106, Bruderer 2013) can give rise to the double-peaked structure observed in the SAO 206462 moment 0 map.”