The ALMA view of the protostellar system HH212

Codella, C.; Cabrit, S.; Gueth, F.; Podio, L.; Leurini, S.; Bachiller, R.; Gusdorf, A.; Leflóch, B.; Nisini, B.; Tafalla, M.; Yvart, W.

doi:10.1051/0004-6361/201424103

Cited by 99 publications

(159 citation statements)

References 27 publications

Supporting

Mentioning

145

Contrasting

Order By: Relevance

“…This does not contradict our assumption, but rather reflects the high extinction associated with the HW sources in the region (A v = 500 to 1000, Cunningham et al 2009). For instance, a microjet was recently imaged at high spatial resolution in the HH212 protostellar outflow by Codella et al (2014) in SiO and Podio et al (2015) in SO and SO 2 , without having a counterpart in H 2 emission at 2.12 µm. Our modelling method is the same as presented in Gusdorf et al (2011Gusdorf et al ( , 2012.…”

Section: Discussionmentioning

confidence: 99%

Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A

Güsten

Menten

Flower

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

Context. OH is a key molecule in H 2 O chemistry, a valuable tool for probing physical conditions, and an important contributor to the cooling of shock regions around high-mass protostars. OH participates in the re-distribution of energy from the protostar towards the surrounding Interstellar Medium. Aims. Our aim is to assess the origin of the OH emission from the Cepheus A massive star-forming region and to constrain the physical conditions prevailing in the emitting gas. We thus want to probe the processes at work during the formation of massive stars. Methods. We present spectrally resolved observations of OH towards the protostellar outflows region of Cepheus A with the GREAT spectrometer onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) telescope. Three triplets were observed at 1834.7 GHz, 1837.8 GHz, and 2514.3 GHz (163.4 µm, 163.1 µm between the 2 Π 1/2 J = 3/2 and J = 1/2 states, and 119.2 µm, a ground transition between the 2 Π 3/2 J = 5/2 and J = 3/2 states), at angular resolutions of 16. 3, 16. 3, and 11. 9, respectively. We also present the CO (16-15) spectrum at the same position. We compared the integrated intensities in the redshifted wings to the results of shock models. Results. The two OH triplets near 163 µm are detected in emission, but with blending hyperfine structure unresolved. Their profiles and that of can be fitted by a combination of two or three Gaussians. The observed 119.2 µm triplet is seen in absorption, since its blending hyperfine structure is unresolved, but with three line-of-sight components and a blueshifted emission wing consistent with that of the other lines. The OH line wings are similar to those of CO, suggesting that they emanate from the same shocked structure. Conclusions. Under this common origin assumption, the observations fall within the model predictions and within the range of use of our model only if we consider that four shock structures are caught in our beam. Overall, our comparisons suggest that all the observations might be consistently fitted by a J-type shock model with a high pre-shock density (n H > 10 5 cm −3 ), a high shock velocity ( s 25 km s −1 ), and with a filling factor of the order of unity. Such a high pre-shock density is generally found in shocks associated to high-mass protostars, contrary to low-mass ones.

show abstract

Section: Discussionmentioning

confidence: 99%

Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A

Güsten

Menten

Flower

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…The properties of the observed SO 9 8 −8 7 , SO 10 11 −10 10 , and SO 2 8 2,6 −7 1,7 transitions are summarised in Table 1 (frequency ν 0 in MHz, upper level energy E up in K, S i j μ 2 in D 2 , coefficient for radiative decay A i j in s −1 ). We also report the properties of the SiO 8−7, CO 3−2, and C 17 O 3−2 transitions observed during the same run and presented by Codella et al (2014a), which are also analysed to compare with the SO and SO 2 emission. The obtained data cubes have a spectral resolution of 488 kHz (0.42−0.43 km s −1 ), a typical beam FWHM of 0.…”

Section: Observations and Data Reductionmentioning

confidence: 94%

“…3−0. 4) performed with the SubMillimeter Array (SMA; Lee et al 2006Lee et al , 2007aLee et al , 2008, the IRAM Plateau de Bure (PdB) interferometer Cabrit et al 2007Cabrit et al , 2012, and the Atacama Large Millimeter Array (ALMA; see Lee et al 2014;Codella et al 2014a) reveal the inner ±1 −2 = 450−900 AU collimated jet (width 100 AU) close to the protostar. HH 212 is also associated with a flattened rotating envelope in the equator perpendicular to the jet axis observed firstly with the NRAO Very Large Array (VLA) in NH 3 emission by Wiseman et al (2001) on 6000 AU scales.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO₂emission

Podio

Codella

Gueth

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

Context. The investigation of the disk formation and jet launching mechanism in protostars is crucial to understanding the earliest stages of star and planet formation. Aims. We aim to constrain the physical and dynamical properties of the molecular jet and disk of the HH 212 protostellar system at unprecedented angular scales, exploiting the capabilities of the Atacama Large Millimeter Array (ALMA). Methods. The ALMA observations of HH 212 in emission lines from sulfur-bearing molecules, SO 9 8 −8 7 , SO 10 11 −10 10 , SO 2 8 2,6 −7 1,7 , are compared with simultaneous CO 3−2, SiO 8−7 data. The molecules column density and abundance are estimated using simple radiative transfer models. Results. SO 9 8 −8 7 and SO 2 8 2,6 −7 1,7 show broad velocity profiles. At systemic velocity, they probe the circumstellar gas and the cavity walls. Going from low to high blue-and red-shifted velocities the emission traces the wide-angle outflow and the fast (∼100−200 km s −1 ), collimated (∼90 AU) molecular jet revealing the inner knots with timescales ≤50 yr. The jet transports a massloss rate ≥0.2−2×10 −6 M yr −1 , implying high ejection efficiency (≥0.03−0.3). The SO and SO 2 abundances in the jet are ∼10 −7 −10 −6 . SO 10 11 −10 10 emission is compact and shows small-scale velocity gradients, indicating that it originates partly from the rotating disk previously seen in HCO + and C 17 O, and partly from the base of the jet. The disk mass is ≥0.002−0.013 M and the SO abundance in the disk is ∼10 −8 −10 −7 . Conclusions. SO and SO 2 are effective tracers of the molecular jet in the inner few hundreds AU from the protostar. Their abundances indicate that 1−40% of sulfur is in SO and SO 2 due to shocks in the jet/outflow and/or to ambipolar diffusion at the wind base. The SO abundance in the disk is 3−4 orders of magnitude larger than in evolved protoplanetary disks. This may be due to an SO enhancement in the accretion shock at the envelope-disk interface or in spiral shocks if the disk is partly gravitationally unstable.

show abstract

“…It is not clear whether these sources have rotationally supported disks, or whether magnetic braking at these early ages inhibits disk formation (e.g., Allen et al 2003;Mellon & Li 2008;Li et al 2013). Rotationally supported disks have been observed around some Class 0 protostars (Tobin et al 2012(Tobin et al , 2013Murillo et al 2013;Codella et al 2014;Lindberg et al 2014;Aso et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Sheehan

Eisner

2017

ApJ

View full text Add to dashboard Cite

Class I protostars are thought to represent an early stage in the lifetime of protoplanetary disks, when they are still embedded in their natal envelope. Here we measure the disk masses of 10 Class I protostars in the Taurus Molecular Cloud to constrain the initial mass budget for forming planets in disks. We use radiative transfer modeling to produce synthetic protostar observations and fit the models to a multi-wavelength data set using a Markov Chain Monte Carlo fitting procedure. We fit these models simultaneously to our new Combined Array for Research in Millimeter-wave Astronomy 1.3 mm observations that are sensitive to the wide range of spatial scales that are expected from protostellar disks and envelopes so as to be able to distinguish each component, as well as broadband spectral energy distributions compiled from the literature. We find a median disk mass of  M 0.018 on average, more massive than the Taurus Class II disks, which have median disk mass of~ M 0.0025 . This decrease in disk mass can be explained if dust grains have grown by a factor of 75 in grain size, indicating that by the Class II stage, at a few Myr, a significant amount of dust grain processing has occurred. However, there is evidence that significant dust processing has occurred even during the Class I stage, so it is likely that the initial mass budget is higher than the value quoted here.

show abstract

The ALMA view of the protostellar system HH212

Cited by 99 publications

References 27 publications

Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A

Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO₂emission

Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Contact Info

Product

Resources

About

The ALMA view of the protostellar system HH212

Cited by 99 publications

References 27 publications

Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A

Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO2emission

Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Contact Info

Product

Resources

About

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO₂emission