The Vla Nascent Disk and Multiplicity Survey: First Look at Resolved Candidate Disks Around Class 0 and I Protostars in the Perseus Molecular Cloud

Segura-Cox, Dominique; Harris, Robert J.; Tobin, John J.; Looney, Leslie W.; Li, Zhi Yun; Chandler, Claire J.; Kratter, Kaitlin M.; Dunham, Michael M.; Sadavoy, Sarah; Pérez, Laura; Melis, Carl

doi:10.3847/2041-8205/817/2/l14

Cited by 62 publications

(104 citation statements)

References 44 publications

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“…This gradient suggests that the binary system is physically linked (Chen et al 2009). A study of dust continuum emission at 8 mm by Segura-Cox et al (2016) suggests a Keplerian disk with a radius 25 au. A similar study from CALYPSO observations at 1.3 mm also suggests an unresolved Keplerian disk with a radius <60 au (Maury et al 2019).…”

Section: Appendix H: Comments On Individual Sourcesmentioning

confidence: 99%

Angular momentum profiles of Class 0 protostellar envelopes

Gaudel

Maury

Беллоче

et al. 2020

A&A

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Context. Understanding the initial properties of star forming material and how they affect the star formation process is a key question. The infalling gas must redistribute most of its initial angular momentum inherited from prestellar cores before reaching the central stellar embryo. Disk formation has been naturally considered as a possible solution to this "angular momentum problem". However, how the initial angular momentum of protostellar cores is distributed and evolves during the main accretion phase and the beginning of disk formation has largely remained unconstrained up to now. Aims. In the framework of the IRAM CALYPSO survey, we obtained observations of the dense gas kinematics that we used to quantify the amount and distribution of specific angular momentum at all scales in collapsing-rotating Class 0 protostellar envelopes. Methods. We used the high dynamic range C 18 O (2−1) and N 2 H + (1−0) datasets to produce centroid velocity maps and probe the rotational motions in the sample of 12 envelopes from scales ∼50 to ∼5000 au. Results. We identify differential rotation motions at scales 1600 au in 11 out of the 12 protostellar envelopes of our sample by measuring the velocity gradient along the equatorial axis, which we fit with a power-law model v ∝ r α . This suggests that coherent motions dominate the kinematics in the inner protostellar envelopes. The radial distributions of specific angular momentum in the CALYPSO sample suggest the following two distinct regimes within protostellar envelopes: the specific angular momentum decreases as j ∝ r 1.6±0.2 down to ∼1600 au and then tends to become relatively constant around ∼6 × 10 −4 km s −1 pc down to ∼50 au. Conclusions. The values of specific angular momentum measured in the inner Class 0 envelopes suggest that material directly involved in the star formation process (<1600 au) has a specific angular momentum on the same order of magnitude as what is inferred in small T-Tauri disks. Thus, disk formation appears to be a direct consequence of angular momentum conservation during the collapse. Our analysis reveals a dispersion of the directions of velocity gradients at envelope scales >1600 au, suggesting that these gradients may not be directly related to rotational motions of the envelopes. We conclude that the specific angular momentum observed at these scales could find its origin in other mechanisms, such as core-forming motions (infall, turbulence), or trace an imprint of the initial conditions for the formation of protostellar cores.

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Section: Appendix H: Comments On Individual Sourcesmentioning

confidence: 99%

Angular momentum profiles of Class 0 protostellar envelopes

Gaudel

Maury

Беллоче

et al. 2020

A&A

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“…A few studies have compared the observations of Class 0 protostars to the outcome of models, either vanalytically (see, e.g., Frau et al 2011) or from magneto-hydrodynamical simulations (see, e.g., Maury et al 2010Maury et al , 2018. These studies have shown that magnetized models of protostellar formation better reproduce the observed small-scale properties of the youngest accreting protostars, for instance the lack of fragmentation and paucity of large (100 < r disk < 500 au) rotationally supported disks (Maury et al 2010(Maury et al , 2014Enoch et al 2011;Segura-Cox et al 2016) observed in Class 0 objects.…”

Section: Introductionmentioning

confidence: 99%

SMA observations of polarized dust emission in solar-type Class 0 protostars: Magnetic field properties at envelope scales

Galametz

Maury

Girart

et al. 2018

A&A

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Aims. Although from a theoretical point of view magnetic fields are believed to play a significant role during the early stages of star formation, especially during the main accretion phase, the magnetic field strength and topology is poorly constrained in the youngest accreting Class 0 protostars that lead to the formation of solar-type stars. Methods. We carried out observations of the polarized dust continuum emission with the SMA interferometer at 0.87 mm to probe the structure of the magnetic field in a sample of 12 low-mass Class 0 envelopes in nearby clouds, including both single protostars and multiple systems. Our SMA observations probed the envelope emission at scales ∼600 − 5000 au with a spatial resolution ranging from 600 to 1500 au depending on the source distance. Results. We report the detection of linearly polarized dust continuum emission in all of our targets with average polarization fractions ranging from 2% to 10% in these protostellar envelopes. The polarization fraction decreases with the continuum flux density, which translates into a decrease with the H 2 column density within an individual envelope. Our analysis show that the envelope-scale magnetic field is preferentially observed either aligned or perpendicular to the outflow direction. Interestingly, our results suggest for the first time a relation between the orientation of the magnetic field and the rotational energy of envelopes, with a larger occurrence of misalignment in sources in which strong rotational motions are detected at hundreds to thousands of au scales. We also show that the best agreement between the magnetic field and outflow orientation is found in sources showing no small-scale multiplicity and no large disks at ∼100 au scales.

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“…Maury et al 2010), but recently discs with radii > 30 au have been found around both Class 0 and I objects (e.g. Lee et al 2009;Choi et al 2010;Tobin et al 2012;Yen et al 2013;Codella et al 2014;Ohashi et al 2014;Harsono et al 2014;Tobin et al 2015;Aso et al 2015; Segura-Cox et al 2016;Yen et al 2017;Aso et al 2017). One hierarchical triple system even displays the sort of disc morphology that would be expected if the wider component had recently formed via the fragmentation of a circumbinary disc .…”

Section: Introductionmentioning

confidence: 99%

On the diversity and statistical properties of protostellar discs

Bate

2018

Monthly Notices of the Royal Astronomical Society

311

320

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We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star-disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to ≈ 10 5 yrs. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order ten to a few hundred au, grow in size on timescales ∼ < 10 4 yr, and are smaller around lower-mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Σ ∝ r −1. Disc to protostar mass ratios rarely exceed two, with a typical range of M d /M * = 0.1−1 to ages ∼ < 10 4 yrs and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.

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The Vla Nascent Disk and Multiplicity Survey: First Look at Resolved Candidate Disks Around Class 0 and I Protostars in the Perseus Molecular Cloud

Cited by 62 publications

References 44 publications

Angular momentum profiles of Class 0 protostellar envelopes

Angular momentum profiles of Class 0 protostellar envelopes

SMA observations of polarized dust emission in solar-type Class 0 protostars: Magnetic field properties at envelope scales

On the diversity and statistical properties of protostellar discs

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