Erratum: “A Survey of C<sub>2</sub>H, HCN, and C<sup>18</sup>O in Protoplanetary Disks” (2019, ApJ, 876, 25)

Bergner, Jennifer B.; Öberg, Karin I.; Bergin, Edwin A.; Loomis, Ryan A.; Pegues, Jamila; Qi, Chunhua

doi:10.3847/1538-4357/ab98f7

Cited by 13 publications

(32 citation statements)

References 2 publications

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“…Figure 1 compares the dust continuum fluxes of our M4-M5 disk sample to dust continuum fluxes of solar-type and Herbig Ae disks (compiled from the chemistry surveys of Huang et al 2017;Bergner et al 2019Bergner et al , 2020Pegues et al 2020, discussed further in Section 4.3). Figure 1 also compares our sample to the dust continuum flux detections from Andrews et al (2013) and from Pascucci et al (2016), which were extracted from the Taurus and Chamaeleon I starforming regions, respectively.…”

Section: Diskmentioning

confidence: 99%

“…This in turn permits tighter constraints on the model fit. We use a hyperfine pixel-by-pixel procedure based on the work of Bergner et al (2019), which in turn was adapted from the fitting procedure of Estalella (2017) and the calculations of Mangum & Shirley (2015). See Appendix B for the model equations, the fitting procedure, examples of model fits, and important discussion of intrinsic uncertainties.…”

Section: Pixel-by-pixel Hyperfine Fitsmentioning

confidence: 99%

“…We now compare relative line fluxes (i.e., the flux for one molecular line with respect to the flux of a different molecular line) for the M4-M5 disks in this work to relative line fluxes measured for solar-type and Herbig Ae disks in the literature. The literature disk sample was compiled from the chemistry surveys of Huang et al (2017), Bergner et al (2019), Bergner et al (2020), andPegues et al (2020). We use only the molecular line+disk pairs in these surveys that were detected with ALMA, leading to thirteen unique disks in all with at least two detections of C 18 O, C 2 H, DCN, HCN, and H 2 CO line emission.…”

Section: Relative Line Fluxes Toward Disks Around M4-m5mentioning

confidence: 99%

“…In Section 4, we present the detections, emission morphologies, relative fluxes and flux correlations, and estimates of molecular column densities, excitation temperatures, and optical depths. In Section 5, we discuss the results, and we compare M4-M5 disk chemistry from our sample with solar-type counterparts from previous molecular surveys (Huang et al 2017;Bergner et al 2019Bergner et al , 2020Pegues et al 2020). In Section 6, we summarize the key findings of our survey.…”

Section: Introductionmentioning

confidence: 96%

“…The white points are ALMAobserved 1.1mm or 1.3mm continuum flux detections (whichever is available) for solar-type disks (marked with squares) and Herbig Ae disks (marked with crosses). These disks were compiled from Huang et al (2017), Bergner et al (2019), Bergner et al (2020), and Pegues et al (2020). This is the same compilation used later in Section 4.3.…”

Section: Introductionmentioning

confidence: 99%

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An ALMA Survey of Chemistry in Disks around M4-M5 Stars

Pegues,

Oberg,

Bergner

et al. 2021

Preprint

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M-stars are the most common hosts of planetary systems in the Galaxy. Protoplanetary disks around M-stars thus offer a prime opportunity to study the chemistry of planet-forming environments. We present an ALMA survey of molecular line emission toward a sample of five protoplanetary disks around M4-M5 stars (FP Tau, J0432+1827, J1100-7619, J1545-3417, and Sz 69). These observations can resolve chemical structures down to tens of AU. Molecular lines of 12 CO, 13 CO, C 18 O, C 2 H, and HCN are detected toward all five disks. Lines of H 2 CO and DCN are detected toward 2/5 and 1/5 disks, respectively. For disks with resolved C 18 O, C 2 H, HCN, and H 2 CO emission, we observe substructures similar to those previously found in disks around solartype stars (e.g., rings, holes, and plateaus). C 2 H and HCN excitation conditions estimated interior to the pebble disk edge for the bright disk J1100-7619 are consistent with previous measurements around solar-type stars. The correlation previously found between C 2 H and HCN fluxes for solar-type disks extends to our M4-M5 disk sample, but the typical C 2 H/HCN ratio is higher for the M4-M5 disk sample. This latter finding is reminiscent of the hydrocarbon enhancements found by previous observational infrared surveys in the innermost (<10AU) regions of M-star disks, which is intriguing since our disk-averaged fluxes are heavily influenced by flux levels in the outermost disk, exterior to the pebble disk edge. Overall, most of the observable chemistry at 10-100AU appears similar for solar-type and M4-M5 disks, but hydrocarbons may be more abundant around the cooler stars.

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Section: Diskmentioning

confidence: 99%

Section: Pixel-by-pixel Hyperfine Fitsmentioning

confidence: 99%

Section: Relative Line Fluxes Toward Disks Around M4-m5mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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An ALMA Survey of Chemistry in Disks around M4-M5 Stars

Pegues,

Oberg,

Bergner

et al. 2021

Preprint

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Launching the asymmetric bipolar jet of DO Tau

Erkal

Dougados

Coffey

et al. 2021

A&A

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Context. The role of bipolar jets in the formation of stars, and in particular how they are launched, is still not well understood. Aims. We probe the protostellar jet launching mechanism using high-resolution observations of the near-infrared (IR) [Fe II]λ1.53,1.64 μm emission lines. Methods. We consider the case of the bipolar jet from Classical T Tauri star, DO Tau, and investigate the jet morphology and kinematics close to the star (within 140 au) using AO-assisted IFU observations from GEMINI/NIFS. Results. We find that the brighter, blueshifted jet is collimated very quickly after it is launched. This early collimation requires the presence of magnetic fields. We confirm velocity asymmetries between the two lobes of the bipolar jet, and also confirm no time variability in the asymmetry over a 20-year interval. This sustained asymmetry is in accordance with recent simulations of magnetised disc winds. We examine the data for signatures of jet rotation. We report an upper limit on differences in radial velocity of 6.3 and 8.7 km s−1 for the blue- and redshifted jets, respectively. Interpreting this as an upper limit on jet rotation implies that any steady, axisymmetric magneto-centrifugal model of jet launching is constrained to a launch radius in the disc plane of r0 < 0.5 and 0.3 au for the blue- and redshifted jets, respectively. This supports an X-wind or narrow disc-wind model. However, the result pertains only to the observed high-velocity [Fe II] emission, and does not rule out a wider flow launched from a wider radius. We report the detection of small-amplitude jet axis wiggling in both lobes. We rule out orbital motion of the jet source as the cause. Precession can better account for the observations but requires double the precession angle, and a different phase for the counter-jet. Such non-solid body precession could arise from an inclined massive Jupiter companion, or a warping instability induced by launching a magnetic disc wind. Conclusions. Overall, our observations are consistent with an origin of the DO Tau jets from the inner regions of the disc.

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CO isotopolog line fluxes of viscously evolving disks

Trapman

Bosman

Rosotti

et al. 2021

A&A

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Context. Protoplanetary disks are thought to evolve viscously, where the disk mass – the reservoir available for planet formation – decreases over time as material is accreted onto the central star over a viscous timescale. Observations have shown a correlation between disk mass and the stellar mass accretion rate, as expected from viscous theory. However, this happens only when using the dust mass as a proxy of the disk mass; the gas mass inferred from CO isotopolog line fluxes, which should be a more direct measurement, shows no correlation with the stellar mass accretion rate. Aims. We investigate how 13CO and C18O J = 3−2 line fluxes, commonly used as gas mass tracers, change over time in a viscously evolving disk and use them together with gas disk sizes to provide diagnostics of viscous evolution. In addition, we aim to determine if the chemical conversion of CO through grain-surface chemistry combined with viscous evolution can explain the CO isotopolog observations of disks in Lupus. Methods. We ran a series of thermochemical DALI models of viscously evolving disks, where the initial disk mass is derived from observed stellar mass accretion rates. Results. While the disk mass, Mdisk, decreases over time, the 13CO and C18O J = 3−2 line fluxes instead increase over time due to their optically thick emitting regions growing in size as the disk expands viscously. The C18O 3–2 emission is optically thin throughout the disk for only for a subset of our models (M*≤ 0.2 M⊙ and αvisc ≥ 10−3, corresponding to Mdisk(t = 1 Myr) ≤ 10−3 M⊙). For these disks the integrated C18O flux decreases with time, similar to the disk mass. Observed 13CO and C18O 3–2 fluxes of the most massive disks (Mdisk ≳ 5 × 10−3 M⊙) in Lupus can be reproduced to within a factor of ~2 with viscously evolving disks in which CO is converted into other species through grain-surface chemistry with a moderate cosmic-ray ionization rate of ζcr ~ 10−17 s−1. The C18O 3–2 fluxes for the bulk of the disks in Lupus (with Mdisk ≲ 5 × 10−3 M⊙) can be reproduced to within a factor of ~2 by increasing ζcr to ~ 5 × 10−17−10−16 s−1, although explaining the stacked upper limits requires a lower average abundance than our models can produce. In addition, increasing ζcr cannot explain the observed 13CO fluxes for lower mass disks, which are more than an order of magnitude fainter than what is predicted. In our models the optically thick 13CO emission originates from a layer higher up in the disk (z∕r ~ 0.25−0.4) where photodissociation stops the conversion of CO into other species. Reconciling the 13CO fluxes of viscously evolving disks with the observations requires either efficient vertical mixing or low mass disks (Mdust ≲ 3 × 10−5 M⊙) being much thinner and/or smaller than their more massive counterparts. Conclusions. The 13CO model flux predominantly traces the disk size, but the C18O model flux traces the disk mass of our viscously evolving disk models if chemical conversion of CO is included. The discrepancy between the CO isotopolog line fluxes of viscously evolving disk models and the observations suggests that CO is efficiently vertically mixed or that low mass disks are smaller and/or colder than previously assumed.

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Erratum: “A Survey of C₂H, HCN, and C¹⁸O in Protoplanetary Disks” (2019, ApJ, 876, 25)

Cited by 13 publications

References 2 publications

An ALMA Survey of Chemistry in Disks around M4-M5 Stars

An ALMA Survey of Chemistry in Disks around M4-M5 Stars

Launching the asymmetric bipolar jet of DO Tau

CO isotopolog line fluxes of viscously evolving disks

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Erratum: “A Survey of C2H, HCN, and C18O in Protoplanetary Disks” (2019, ApJ, 876, 25)

Cited by 13 publications

References 2 publications

An ALMA Survey of Chemistry in Disks around M4-M5 Stars

An ALMA Survey of Chemistry in Disks around M4-M5 Stars

Launching the asymmetric bipolar jet of DO Tau

CO isotopolog line fluxes of viscously evolving disks

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Product

Resources

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Erratum: “A Survey of C₂H, HCN, and C¹⁸O in Protoplanetary Disks” (2019, ApJ, 876, 25)