A search for shock-excited molecular hydrogen knots in Chamaeleon I very low mass YSOs

Gómez, Mercedes; Persi, P.; Marenzi, Anna; Roth, Markus; Tapia, M.

doi:10.1051/0004-6361:20047173

Cited by 11 publications

(11 citation statements)

References 51 publications

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“…Although some shocks exhibit infrared emission in the IRAC bands, most notably HH 49/50 (the ''tornado''), most outflows in the Cha I clouds are not detected in the Spitzer IRAC bands. This result is consistent with the general lack of extensive 2.12 m emission from Cha I reported by Gómez et al (2004).…”

Section: Introductionsupporting

confidence: 92%

Deep Imaging Surveys of Star-forming Clouds. IV. The Meek and the Mighty: Outflows from Young Stars in Chamaeleon I

et al. 2006

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We present a survey of shocks and outflows in the Chamaeleon I star-forming complex using H , [S ii], and SDSS i 0 images obtained from the ground, an i 0 image obtained with the Hubble Space Telescope, and 4.5 m images obtained with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We find new Herbig-Haro ( HH ) objects and extensions to the previously cataloged shocks that trace parts of at least 20 distinct outflows from young stars. Some HH objects mark the presence of giant outflows, the largest of which is powered by Cha-MMS1 and associated with HH 49/50 near the Ced 110 region. Other large flows are powered by Cha-MMS2 in the Ced 112 region and the IRN in the Ced 111 region. Although some shocks exhibit infrared emission in the IRAC bands, most notably HH 49/50 (the ''tornado''), most outflows in the Cha I clouds are not detected in the Spitzer IRAC bands. This result is consistent with the general lack of extensive 2.12 m H 2 emission from Cha I.

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Section: Introductionsupporting

confidence: 92%

Deep Imaging Surveys of Star-forming Clouds. IV. The Meek and the Mighty: Outflows from Young Stars in Chamaeleon I

et al. 2006

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“…The three clouds have similar masses as traced with 13 CO 1−0 (∼1000 M ), but the fraction of denser gas traced with C 18 O 1−0 is the highest in Cha I (24%), while it is the lowest in Cha III (4%) (Mizuno et al 1999(Mizuno et al , 2001. Finally, several indications of jets/outflows were found in Cha I (Mattila et al 1989;Gómez et al 2004;Wang & Henning 2006;Belloche et al 2006). Only three Herbig-Haro objects are known in Cha II and none has been found in Cha III (Schwartz 1977).…”

Section: Introductionmentioning

confidence: 85%

Will the starless cores in Chamaeleon I and III turn prestellar?

Беллоче

Parise

Schüller

et al. 2011

A&A

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Context. The nearby Chamaeleon molecular cloud complex is a good laboratory for studying the process of low-mass star formation because it consists of three clouds with very different properties. Chamaeleon III does not show any sign of star formation, while star formation has been very active in Chamaeleon I and may already be finishing. Aims. Our goal is to determine whether star formation can proceed in Cha III by searching for prestellar cores, and to compare the results to our recent survey of Cha I. Methods. We used the Large APEX Bolometer Array (LABOCA) to map Cha III in dust continuum emission at 870 μm. The map is compared with a 2MASS extinction map and decomposed with a multiresolution algorithm. The extracted sources are analyzed by carefully taking into account the spatial filtering inherent in the data reduction process. Results. Twenty-nine sources are extracted from the 870 μm map, all of them starless. The estimated 90% completeness limit is 0.18 M . The starless cores are found down to a visual extinction of 1.9 mag, in marked contrast with other molecular clouds, including Cha I. Apart from this difference, the Cha III starless cores share very similar properties with those found in Cha I. They are less dense than those detected in continuum emission in other clouds by a factor of a few. At most two sources (<7%) have a mass larger than the critical Bonnor-Ebert mass, which suggests that the fraction of prestellar cores is very low, even lower than in Cha I (<17%). Only the most massive sources are candidate prestellar cores, in agreement with the correlation found earlier in the Pipe nebula. The mass distribution of the 85 starless cores of Cha I and III that are not candidate prestellar cores is consistent with a single power law down to the 90% completeness limit, with an exponent close to the Salpeter value. A fraction of the starless cores detected with LABOCA in Cha I and III may still grow in mass and become gravitationally unstable. Based on predictions of numerical simulations of turbulent molecular clouds, we estimate that at most 50% and 20% of the starless cores of Cha I and III, respectively, may form stars. Conclusions. The LABOCA survey reveals that Cha III, and Cha I to some extent too, is a prime target to study the formation of prestellar cores, and thus the onset of star formation. Obtaining observational constraints on the duration of the core-building phase prior to gravitational collapse will be necessary to make further progress.

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“…Persi et al (1999), on the other hand, identified ISOCha I 192 as the driving source of a large-scale 12 CO (1-0) outflow in the region (Mattila et al 1989). Gómez et al (2004) found five H 2 knots that roughly align with the CO outflow direction.…”

Section: Introductionmentioning

confidence: 88%

ISO-Cha I 192: A New Embedded Eruptive Variable in the Chamaeleon I Dark Cloud

Persi¹,

Tapia²,

Gómez³

et al. 2007

Astron J

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We report the detection of an increase of about 2 mag in the 2.2 m brightness of ISO-Cha I 192, a class I low-mass stellar object thought to be driving a bipolar CO outflow in the Chamaeleon I cloud. This substantial brightness change has taken place during less than 3 yr, from 1996 March to 1999 April. An elongated infrared reflection nebula of size $530 AU is seen originating from the star in the direction of the CO bipolar outflow. The historic infrared properties of this young stellar object are examined in order to substantiate the hypothesis that this object is an FU Ori-or EX Luptype system. Combining our new ground-based near-and mid-infrared photometry with Spitzer IRAC and MIPS broadband fluxes supplemented by published recent spectrophotometry, the spectral energy distribution of this source was constructed. We explored the plausibility of a ''standard'' configuration of infalling envelope + disk + central source for this object by fitting a two-dimensional radiative transfer code that includes the contributions of each of these components.

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A search for shock-excited molecular hydrogen knots in Chamaeleon I very low mass YSOs

Cited by 11 publications

References 51 publications

Deep Imaging Surveys of Star-forming Clouds. IV. The Meek and the Mighty: Outflows from Young Stars in Chamaeleon I

Deep Imaging Surveys of Star-forming Clouds. IV. The Meek and the Mighty: Outflows from Young Stars in Chamaeleon I

Will the starless cores in Chamaeleon I and III turn prestellar?

ISO-Cha I 192: A New Embedded Eruptive Variable in the Chamaeleon I Dark Cloud

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