The Formation Conditions of the Wide Binary Class 0 Protostars within BHR 71

Tobin, John J.; Bourke, Tyler L.; Mader, Stacy; Kristensen, L. E.; Arce, Héctor G.; Gueth, F.; Gusdorf, A.; Codella, C.; Leurini, S.; Chen, Xuepeng

doi:10.3847/1538-4357/aaef87

Cited by 30 publications

(33 citation statements)

References 101 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An inclination angle of 90 degrees indicates an edge-on system, and inclination greater than 90 degrees indicates the rotation vector is behind the plane of sky. High resolution ALMA 13 CO observations also indicate an inclination angle between 115 • to 153 • under the same definition (Tobin et al 2019). BHR 71 also shows prominent outflows in the north-south direction (Bourke et al 1997), resulting in several active shocked regions (Garay et al 1998;Gusdorf et al 2011Gusdorf et al , 2015.…”

Section: Introductionmentioning

confidence: 94%

“…BHR 71 is a Bok globule near the Southern Coalsack at 200 pc (Seidensticker & Schmidt-Kaler 1989;Straizys et al 1994), hosting two protostars, IRS1 and IRS2, separated by 16 (Bourke 2001;Tobin et al 2019). Tobin et al (2019) detect opposite velocity gradients toward IRS1 and IRS2, suggesting that the binary system is likely formed via turbulent fragmentation. BHR 71 IRS1 dominates the luminosity of BHR 71 with L = 13.5 L (Yang et al 2018), whereas IRS2 only has 1.7 L (Tobin et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The envelope of BHR 71 shows blue-shifted emission in the east and red-shifted emission in the west, indicating the rotation of the inner envelope (Chen et al 2008;Tobin et al 2019). BHR 71 drives outflows in the northsouth direction (Bourke et al 1997;Parise et al 2006a).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and Its Hot Corino

Yang

Evans

Smith

et al. 2020

ApJ

Self Cite

View full text Add to dashboard Cite

The collapse of the protostellar envelope results in the growth of the protostar and the development of a protoplanetary disk, playing a critical role during the early stages of star formation. Characterizing the gas infall in the envelope constrains the dynamical models of star formation. We present unambiguous signatures of infall, probed by optically thick molecular lines, toward an isolated embedded protostar, BHR 71 IRS1. The three dimensional radiative transfer calculations indicate that a slowly rotating infalling envelope model following the "inside-out" collapse reproduces the observations of both HCO + J = 4 → 3 and CS J = 7 → 6 lines, and the low velocity emission of the HCN J = 4 → 3 line. The envelope has a model-derived age of 12 000±3000 years after the initial collapse. The envelope model underestimates the high velocity emission at the HCN J = 4 → 3 and H 13 CN J = 4 → 3 lines, where outflows or a Keplerian disk may contribute. The ALMA observations serendipitously discover the emission of complex organic molecules (COMs) concentrated within a radius of 100 au, indicating that BHR 71 IRS1 harbors a hot corino. Eight species of COMs are identified, including CH 3 OH and CH 3 OCHO, along with H 2 CS, SO 2 and HCN v 2 = 1. The emission of methyl formate and 13 C-methanol shows a clear velocity gradient within a radius of 50 au, hinting at an unresolved Keplerian rotating disk.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and Its Hot Corino

Yang

Evans

Smith

et al. 2020

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…We obtained M cr = 14.5 − 18.7 M ⊙ with M BE 8.5 M ⊙ . The Bonnor-Ebert mass was estimated using a kinematic temperature T kin of 13 K (Bourke et al 1995b), a turbulent velocity dispersion of 0.2 km s −1 (Tobin et al 2019), and an assumed external pressure of 6 × 10 4 K cm −3 . The assumed external pressure is equivalent to T eff × ρ, where ρ is the mean density of the core and T eff is the sum of the kinematic temperature T kin and the turbulence equivalent temperature T turb = µ p σ 2 turb /k = 10.9 K. The mean molecular weight per free particle µ p is set to 2.33 and k is the Boltzmann constant.…”

Section: Magnetic Properties Of the Core And The Origin Of The Curvedmentioning

confidence: 99%

“…These protostars have misaligned outflows (Bourke 2001;Parise et al 2006). Furthermore, Tobin et al (2019) reported that the rotation of these protostars measured in C 18 O (J = 1 − 0) on scales of < 1000 au around each source is in the opposite direction. These results may be evidence these protostars formed by turbulent fragmentation (Tobin et al 2019), and is consistent with a theoretical simulation of the formation of binary/multiple sources in turbulent environments (Offner et al 2016).…”

Section: Introductionmentioning

confidence: 98%

Distortion of Magnetic Fields in BHR 71

Kandori

Tamura

Saito

et al. 2020

ApJ

View full text Add to dashboard Cite

The magnetic field structure of a star-forming Bok globule BHR 71 was determined based on near-infrared polarimetric observations of background stars. The magnetic field in BHR 71 was mapped from 25 stars. By using a simple 2D parabolic function, the plane-of-sky magnetic axis of the core was found to be θ mag = 125 • ± 11 • . The plane-of-sky mean magnetic field strength of BHR 71 was found to be B pos = 8.8 − 15.0 µG, indicating that the BHR 71 core is magnetically supercritical with λ = 1.44 − 2.43. Taking into account the effect of thermal/turbulent pressure and the plane-of-sky magnetic field component, the critical mass of BHR 71 was M cr = 14.5 − 18.7 M ⊙ , which is consistent with the observed core mass of M core ≈ 14.7 M ⊙ (Yang et al. 2017). We conclude that BHR 71 is in a condition close to a kinematically critical state, and the magnetic field direction lies close to the plane of sky. Since BHR 71 is a star-forming core, a significantly subcritical condition (i.e., the magnetic field direction deviating from the plane of sky) is unlikely, and collapsed from a condition close to a kinematically critical state. There are two possible scenarios to explain the curved magnetic fields of BHR 71, one is an hourglass-like field structure due to mass accumulation and the other is the Inoue & Fukui (2013) mechanism, which proposes the interaction of the core with a shock wave to create curved magnetic fields wrapping around the core.

show abstract

Molecular analysis of a high-mass prestellar core candidate in W43-MM1

Molet

Brouillet

Nony

et al. 2019

A&A

View full text Add to dashboard Cite

Context. High-mass analogues of low-mass prestellar cores are searched for to constrain the models of high-mass star formation. Several high-mass cores, at various evolutionary stages, have been recently identified towards the massive star-forming region W43-MM1 and amongst them a high-mass prestellar core candidate. Aims. We aim to characterise the chemistry in this high-mass prestellar core candidate, referred to as W43-MM1 core #6, and its environment. Methods. Using ALMA high-spatial resolution data of W43-MM1, we have studied the molecular content of core #6 and a neighbouring high-mass protostellar core, referred to as #3, which is similar in size and mass to core #6. We first subtracted the continuum emission using a method based on the density distribution of the intensities on each pixel. Then, from the distribution of detected molecules, we identified the molecules centred on the prestellar core candidate (core #6) and those associated to shocks related to outflows and filament formation. Then we constrained the column densities and temperatures of the molecules detected towards the two cores. Results. While core #3 appears to contain a hot core with a temperature of about 190 K, core #6 seems to have a lower temperature in the range from 20 K to 90 K from a rotational diagram analysis. We have considered different source sizes for core #6 and the comparison of the abundances of the detected molecules towards the core with various interstellar sources shows that it is compatible with a core of size 1000 au with T = 20 − 90 K or a core of size 500 au with T ∼ 80 K. Conclusions. Core #6 of W43-MM1 remains one of the best high-mass prestellar core candidates even if we cannot exclude that it is at the very beginning of the protostellar phase of high-mass star formation.

show abstract

The Formation Conditions of the Wide Binary Class 0 Protostars within BHR 71

Cited by 30 publications

References 101 publications

Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and Its Hot Corino

Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and Its Hot Corino

Distortion of Magnetic Fields in BHR 71

Molecular analysis of a high-mass prestellar core candidate in W43-MM1

Contact Info

Product

Resources

About