The end of star formation in Chamaeleon I?

Беллоче, А.; Schüller, F.; Parise, B.; André, Ph.; Hatchell, J.; Jørgensen, J. K.; Bontemps, Sylvain; Weiß, A.; Menten, K. M.; Muders, D.

doi:10.1051/0004-6361/201015733

Cited by 86 publications

(161 citation statements)

References 86 publications

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“…The values cover a wide range, from 10 20 up to 10 23 cm −2 , and are centred around a few times 10 21 . In comparison with previous studies, the peak of this distribution is lower than the typical values of a few times 10 22 , inferred in cold cores observed from ground-based telescopes in nearby star-forming regions (Motte et al 1998;Kauffmann et al 2008;Enoch et al 2008;Curtis & Richer 2010;Belloche et al 2011). This can be explained by the Planck resolution, that preferentially selects quite extended objects, diluting sources smaller than the 5 beam.…”

Section: Column Densitiescontrasting

confidence: 59%

Planckearly results. XXIII. The first all-sky survey of Galactic cold clumps

Ade¹,

Aghanim²,

Arnaud³

et al. 2011

A&A

154

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We present the statistical properties of the Cold Clump Catalogue of Planck Objects (C3PO), the first all-sky catalogue of cold objects, in terms of their spatial distribution, dust temperature, distance, mass, and morphology. We have combined Planck and IRAS data to extract 10 342 cold sources that stand out against a warmer environment. The sources are distributed over the whole sky, including in the Galactic plane, despite the confusion, and up to high latitudes (>30 • ). We find a strong spatial correlation of these sources with ancillary data tracing Galactic molecular structures and infrared dark clouds where the latter have been catalogued. These cold clumps are not isolated but clustered in groups. Dust temperature and emissivity spectral index values are derived from their spectral energy distributions using both Planck and IRAS data. The temperatures range from 7 K to 19 K, with a distribution peaking around 13 K. The data are inconsistent with a constant value of the associated spectral index β over the whole temperature range: β varies from 1.4 to 2.8, with a mean value around 2.1. Distances are obtained for approximately one third of the objects. Most of the detections lie within 2 kpc of the Sun, but more distant sources are also detected, out to 7 kpc. The mass estimates inferred from dust emission range from 0.4 M to 2.4 × 10 5 M . Their physical properties show that these cold sources trace a broad range of objects, from low-mass dense cores to giant molecular clouds, hence the "cold clump" terminology. This first statistical analysis of the C3PO reveals at least two colder populations of special interest with temperatures in the range 7 to 12 K: cores that mostly lie close to the Sun; and massive cold clumps located in the inner Galaxy. We also describe the statistics of the early cold core (ECC) sample that is a subset of the C3PO, containing only the 915 most reliable detections. The ECC is delivered as a part of the Planck Early Release Compact Source Catalogue (ERCSC).

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Section: Column Densitiescontrasting

confidence: 59%

Planckearly results. XXIII. The first all-sky survey of Galactic cold clumps

Ade¹,

Aghanim²,

Arnaud³

et al. 2011

A&A

154

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“…20). The mass estimate of Cha-MMS1 from continuum observations yields 1.44 M within a radius of 3750 AU (Belloche et al 2011a). …”

Section: Comparison To Theoretical Modelsmentioning

confidence: 97%

“…The flux density measured within a radius of 3750 AU gives a mass of ∼1.44 M for the Cha-MMS1 core (Belloche et al 2011a). We use this value to scale our input density profile.…”

Section: Density Profilementioning

confidence: 99%

“…1. a) 870 μm map of the filament in which Cha-MMS1 is embedded, obtained with LABOCA as part of an unbiased survey of Chamaeleon I (Belloche et al 2011a). The contour levels correspond to −a, a, 2a, 4a, 6a, 8a, 12a, 16a, 24a, 32a, with a = 36 mJy/21 -beam (3σ).…”

Section: Mopra Observationsmentioning

confidence: 99%

“…We compute the centrifugal acceleration and the local gravitational field as where a cen , v rot , Ω, g, G, M env , M obj , and r are the centrifugal acceleration, the rotational velocity, the angular velocity, the gravitational acceleration, the gravitational constant, the envelope mass, the mass of the central object, and the radius, respectively. We assume that the envelope mass is proportional to the radius (density proportional to r −2 ) and that a mass of 1.44 M is enclosed within a radius of 3750 AU, as derived from the LABOCA 870 μm dust continuum map (Belloche et al 2011a). Figure 22 shows the variation of a cen /g as a function of radius.…”

Section: Centrifugal Acceleration and Rotational Energymentioning

confidence: 99%

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The dynamical state of the first hydrostatic core candidate Chamaeleon-MMS1

Tsitali¹,

Беллоче²,

Commerçon³

et al. 2013

A&A

Self Cite

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Context. First hydrostatic cores represent a theoretically predicted intermediate evolutionary link between the prestellar and protostellar phases. Studying the observational characteristics of first core candidates is therefore vital for probing and understanding the earliest phases of star formation. Aims. We aim to determine the dynamical state of the first hydrostatic core candidate Chamaeleon-MMS1 (Cha-MMS1). Methods. We observed Cha-MMS1 in various molecular transitions with the APEX and Mopra telescopes. Continuum data retrieved from the Spitzer Heritage Archive were used to estimate the internal luminosity of the source. The molecular emission was modelled with a radiative transfer code to derive constraints on the kinematics of the envelope, which were then compared to the predictions of magneto-hydrodynamic simulations. Results. We derive an internal luminosity of 0.08 L −0.18 L for Cha-MMS1. An average velocity gradient of 3.1 ± 0.1 km s −1 pc −1 over ∼0.08 pc is found perpendicular to the filament in which Cha-MMS1 is embedded. The gradient is flatter in the outer parts and, surprisingly, also at the innermost ∼2000 AU to 4000 AU. The former features are consistent with solid-body rotation beyond 4000 AU and slower, differential rotation beyond 8000 AU, but the origin of the flatter gradient in the innermost parts is unclear. The classical infall signature is detected in HCO + 3−2 and CS 2−1. The radiative transfer modelling indicates a uniform infall velocity in the outer parts of the envelope. In the inner parts (at most 9000 AU), an infall velocity field scaling with r −0.5 is consistent with the data, but the shape of the profile is less well constrained and the velocity could also decrease toward the centre. The infall velocities are subsonic to transonic, 0.1 km s −1 −0.2 km s −1 at r ≥ 3300 AU, and subsonic to supersonic, 0.04 km s −1 −0.6 km s −1 at r ≤ 3300 AU. Both the internal luminosity of Cha-MMS1 and the infall velocity field in its envelope are consistent with predictions of MHD simulations for the first core phase. There is no evidence of any fast, large-scale outflow stemming from Cha-MMS1, but excess emission from the high-density tracers CS 5−4, CO 6−5, and CO 7−6 suggests the presence of higher velocity material at the inner core. Conclusions. Its internal luminosity excludes Cha-MMS1 being a prestellar core. The kinematical properties of its envelope are consistent with Cha-MMS1 being a first hydrostatic core candidate or a very young Class 0 protostar.

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Recent Star Formation in the Lupus Clouds as Seen by Herschel

Rygl

Benedettini

2014

The Labyrinth of Star Formation

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We present a study of the star formation histories of the Lupus I, III, and IV clouds using the Herschel 70-500 µm maps obtained by the Herschel Gould Belt Survey Key Project. By combining the new Herschel data with the existing Spitzer catalog we obtained an unprecedented census of prestellar sources and young stellar objects in the Lupus clouds, which allowed us to study the overall star formation rate (SFR) and efficiency (SFE). The high SFE of Lupus III, its decreasing SFR, and its large number of pre-main sequence stars with respect to proto-and prestellar sources, suggest that Lupus III is the most evolved cloud, and after having experienced a major star formation event in the past, is now approaching the end of its current star-forming cycle. Lupus I is currently undergoing a large star formation event, apparent by the increasing SFR, the large number of prestellar objects with respect to more evolved objects, and the high percentage of material at high extinction (e.g., above A V ≈ 8 mag). Also Lupus IV has an increasing SFR; however, the relative number of prestellar sources is much lower, suggesting that its star formation has not yet reached its peak.

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The end of star formation in Chamaeleon I?

Cited by 86 publications

References 86 publications

Planckearly results. XXIII. The first all-sky survey of Galactic cold clumps

Planckearly results. XXIII. The first all-sky survey of Galactic cold clumps

The dynamical state of the first hydrostatic core candidate Chamaeleon-MMS1

Recent Star Formation in the Lupus Clouds as Seen by Herschel

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