Multigenerational Star Formation in L1551

Moriarty‐Schieven, G. H.; Johnstone, Doug; Bally, John; Jenness, Tim

doi:10.1086/500357

Cited by 50 publications

(77 citation statements)

References 58 publications

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“…Since low mass protostars evolve approximately at the same rate to the main sequence, the different evolutionary stages found in I00213 suggest that stars in this region are not forming simultaneously but continuously. Also, there may be different generations due to different timescales of core collapse, as has been found in other low mass star-forming regions (e.g., L1551: Moriarty-Schieven et al 2006), indicating that the formation of different stars is not simultaneous but sequential in time, possibly triggered by the interaction of the molecular outflow with a dense core in its surroundings (Yokogawa et al 2003;Shimajiri et al 2008). Therefore, the initial assumption that star formation occurs in an isolated mode may not be appropriate to describe the I00213 region when the region is studied with high angular resolution.…”

Section: Discussionmentioning

confidence: 89%

Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530

Busquet¹,

Palau

Estalella³

et al. 2009

A&A

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Aims. The aim of this paper is to study with high angular resolution a dense core associated with a low-luminosity IRAS source, IRAS 00213+6530, in order to investigate whether low mass star formation is taking place in isolation. Methods. We carried out observations at 1.2 mm with the IRAM 30 m telescope, and VLA observations in the continuum mode at 6 cm, 3.6 cm, 1.3 cm and 7 mm, together with H 2 O maser and NH 3 lines toward IRAS 00213+6530. Additionally, we observed the CCS J N = 2 1 -1 0 transition, and H 2 O maser emission using the NASA 70 m antenna at Robledo de Chavela, Spain. We studied the nature of the centimeter and millimeter emission of the young stellar objects (YSOs) found in the region, and the physical properties of the dense gas and dust emission. Results. The centimeter and millimeter continuum emission, together with the near infrared data from 2MASS allowed us to identify three YSOs, IRS 1, VLA 8A, and VLA 8B, with different radio and infrared properties, and which seem to be in different evolutionary stages. IRS 1, detected only in the infrared, is in the more advanced stage. On the other hand, VLA 8A, bright at centimeter and millimeter wavelengths, coincides with a near infrared 2MASS source, whereas VLA 8B has no infrared emission associated with it and is in the earliest evolutionary stage. The overall structure of the NH 3 emission consists of three clouds. Two of these, MM1 and MM2, are associated with dust emission at millimeter wavelengths, while the southern cloud is only detected in NH 3 . The YSOs are embedded in MM1, where we found evidence of line broadening and temperature enhancements. On the other hand, the southern cloud and MM2 appear to be quiescent and starless. Concerning the 1.2 mm dust emission, we modeled the radial intensity profile of MM1. The model fits the data reasonably well, but it underestimates the intensity at small projected distances from the 1.2 mm peak, probably due to the presence of multiple YSOs embedded in the dusty envelope. There is a strong differentiation in the relative NH 3 abundance with low values of ∼2 × 10 −8 toward MM1, which harbors the YSOs, and high values, up to 10 −6 , toward the southern cloud and MM2, suggesting that these clouds could be in a young evolutionary stage. Conclusions. IRAS 00213+6530 harbors a multiple system of low-mass protostars, indicating that star formation in this cloud is taking place in groups or clusters, rather than in isolation. The low-mass YSOs found in IRAS 00213+6530 are in different evolutionary stages, suggesting that star formation takes place in different episodes.

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Section: Discussionmentioning

confidence: 89%

Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530

Busquet¹,

Palau

Estalella³

et al. 2009

A&A

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“…The SED in the MIR has been measured with ISOCAM/ISO (Stapelfeldt & Moneti 1999;Brandner et al 2000) and refined substantially by observations with IRS on the Spitzer Space Telescope (SST, Furlan et al 2008). Mapping of continuum fluxes at (sub)mm-wavelengths, observations of rotational transitions of CO isotopes and HCO + , and high-resolution imaging with interferometers have provided valuable insights revealing the dynamics of the gaseous component, its temperature distribution and the very low spectral index β mm ∼ 0.4 of the dust (Reipurth et al 1993;Padgett et al 2001;Moriarty-Schieven et al 2006;P06;G08). We will present the most prominent observations used for this study in the following paragraphs, the photometric data is shown in Fig.…”

Section: Observationsmentioning

confidence: 99%

The circumstellar disk of HH 30

Madlener

Wolf

Dutrey

et al. 2012

A&A

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Context. Circumstellar disks are characteristic for star formation and vanish during the first few Myr of stellar evolution. During this time planets are believed to form in the dense midplane by growth, sedimentation and aggregation of dust. Indicators of disk evolution, such as holes and gaps, can be traced in the spectral energy distribution (SED) and spatially resolved images. Aims. We aim to construct a self-consistent model of HH 30 by fitting all available continuum observations simultaneously. New data sets not available in previous studies, such as high-resolution interferometric imaging with the Plateau de Bure Interferometer (PdBI) at λ = 1.3 mm and SED measured with IRS on the Spitzer Space Telescope in the mid-infrared, put strong constraints on predictions and are likely to provide new insights into the evolutionary state of this object. Methods. A parameter study based on simulated annealing was performed to find unbiased best-fit models for independent observations made in the wavelength domain λ ∼ 1 μm . . . 4 mm. The method essentially creates a Markov chain through parameter space by comparing predictions generated by our self-consistent continuum radiation transfer code MC3D with observations. Results. We present models of the edge-on circumstellar disk of HH 30 based on observations from the near-infrared to mmwavelengths that suggest the presence of an inner depletion zone with ∼45 AU radius and a steep decline of mm opacity beyond 140 AU. Our modeling indicates that several modes of dust evolution such as growth, settling, and radial migration are taking place in this object. Conclusions. High-resolution observations of HH 30 at different wavelengths with next-generation observatories such as ALMA and JWST will enable the modeling of inhomogeneous dust properties and significantly expand our understanding of circumstellar disk evolution.

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“…This strange behaviour was the main reason for several authors to consider this flow as an intersection of two jets: one from HL Tau and another from the hypothetical source VLA 1 (Mundt et al 1987). But sub-millimeter (Moriarty-Schieven et al 2006) and various infrared observations of this region did not confirm the existence of any source in the position of the VLA 1. Presently the HH 151 jet is considered as a single flow from HL Tau itself.…”

Section: Introductionmentioning

confidence: 97%

Kinematics and the origin of the internal structures in HL Tauri jet (HH 151)

Movsessian

Magakian

Моисеев

2012

A&A

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Context. Knotty structures of Herbig-Haro jets are common phenomena, and knowing the origin of these structures is essential for understanding the processes of jet formation. Basically, there are two theoretical approaches: different types of instabilities in stationary flow, and velocity variations in the flow. Aims. We investigate the structures with different radial velocities in the knots of the HL Tau jet as well as its unusual behaviour starting from 20 from the source. Collation of radial velocity data with proper motion measurements of emission structures in the jet of HL Tau makes it possible to understand the origin of these structures and decide on the mechanism for the formation of the knotty structures in Herbig-Haro flows. Methods. We present observations obtained with a 6 m telescope (Russia) using the SCORPIO camera with scanning Conclusions. We conclude that the high-and low-velocity structures in the HL Tau jet represent bow-shocks and Mach disks in the internal working surfaces of episodic outflows. The bend of the jet and the brightness increase starting some distance from the source coincides with the observed stationary deflecting shock. The increase of relative surface brightness of bow-shocks could be the result of the abrupt change of the physical conditions of the ambient medium as well as the interaction of a highly collimated flow and the side wind from XZ Tau.

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Multigenerational Star Formation in L1551

Cited by 50 publications

References 58 publications

Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530

Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530

The circumstellar disk of HH 30

Kinematics and the origin of the internal structures in HL Tauri jet (HH 151)

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