Outflows, infall and evolution of a sample of embedded low-mass protostars

Mottram, J. C.; Dishoeck, E. F. van; Kristensen, L. E.; Karska, A.; José-García, I. San; Khanna, Shourya; Herczeg, G. J.; Andr, Ph.; Bontemps, Sylvain; Cabrit, S.; Carney, M. T.; Drozdovskaya, M. N.; Dunham, Michael M.; Evans, Neal J.; Fedele, D.; Green, J. D.; Harsono, Daniel; Johnstone, Doug; Jørgensen, J. K.; Könyves, V.; Nisini, B.; Persson, M. V.; Tafalla, M.; Visser, R.; Yıldız, U. A.

doi:10.1051/0004-6361/201628682

Cited by 69 publications

(147 citation statements)

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“…A slow asymmetrical molecular outflow was first mapped in CO by Mitchell et al (1997), which was mainly associated to the receding atomic jet. Mottram et al (2017) show that both CO lobes extend up to at least 60 (8400 au) with opening angles similar to the infrared scattering nebulae. They also show the absence of HCO+ emission on source, which is typical for young stars with weak envelopes (van Kempen et al 2009).…”

Section: Introductionmentioning

confidence: 55%

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ALMA reveals a large structured disk and nested rotating outflows in DG Tauri B

Valon

Dougados

Cabrit

et al. 2020

A&A

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We present Atacama Large Millimeter Array (ALMA) Band 6 observations at 14-20 au spatial resolution of the disk and CO(2-1) outflow around the Class I protostar DG Tau B in Taurus. The disk is very large, both in dust continuum (R eff,95% =174 au) and CO (R CO =700 au). It shows Keplerian rotation around a 1.1±0.2 M central star and two dust emission bumps at r = 62 and 135 au. These results confirm that large structured disks can form at an early stage where residual infall is still ongoing. The redshifted CO outflow at high velocity shows a striking hollow cone morphology out to 3000 au with a shear-like velocity structure within the cone walls. These walls coincide with the scattered light cavity, and they appear to be rooted within < 60 au in the disk. We confirm their global average rotation in the same sense as the disk, with a specific angular momentum 65 au km s −1 . The mass-flux rate of 1.7-2.9 × 10 −7 M yr −1 is 35±10 times that in the atomic jet. We also detect a wider and slower outflow component surrounding this inner conical flow, which also rotates in the same direction as the disk. Our ALMA observations therefore demonstrate that the inner cone walls, and the associated scattered light cavity, do not trace the interface with infalling material, which is shown to be confined to much wider angles (> 70 • ). The properties of the conical walls are suggestive of the interaction between an episodic inner jet or wind with an outer disk wind, or of a massive disk wind originating from 2-5 au. However, further modeling is required to establish their origin. In either case, such massive outflow may significantly affect the disk structure and evolution.

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Section: Introductionmentioning

confidence: 55%

“…3.1 and 3.2.2). However, by extrapolating the single-dish fluxes obtained by Mottram et al (2017) at 450µm and 850µm, we find that the extended dust envelope around DG Tau B contributes only 300 +400 −300 mJy at 1.3mm, that is, at most comparable to the disk flux itself. Following Eq.…”

Section: Dg Tau B Disk: Evolutionary Stage and Origin Of Structurementioning

confidence: 85%

ALMA reveals a large structured disk and nested rotating outflows in DG Tauri B

Valon

Dougados

Cabrit

et al. 2020

A&A

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“…Millimetre observations of class 0 sources confirm that bipolar outflows and jets are ubiquitous at this evolutionary stage and represent a fundamental output of the star formation process (e.g. Mottram et al 2017, Nisini et al 2015. The role of jets in more evolved sources is less clear, although powerful optical jets are commonly observed in very active Classical T Tauri (CTT) stars.…”

Section: Introductionmentioning

confidence: 99%

Connection between jets, winds and accretion in T Tauri stars

Nisini

Antoniucci

Alcalá

et al. 2018

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Mass loss from jets and winds is a key ingredient in the evolution of accretion discs in young stars. While slow winds have been recently extensively studied in T Tauri stars, little investigation has been devoted on the occurrence of high velocity jets and on how the two mass-loss phenomena are connected with each other, and with the disc mass accretion rates. In this framework, we have analysed the [O i]6300Å line in a sample of 131 young stars with discs in the Lupus, Chamaeleon and σ Orionis star forming regions. The stars were observed with the X-shooter spectrograph at the Very Large Telescope (VLT) and have mass accretion rates spanning from 10 −12 to 10 −7 M ⊙ yr −1 . The line profile was deconvolved into a low velocity component (LVC, |V r | < 40km s −1 ) and a high velocity component (HVC, |V r | > 40km s −1 ), originating from slow winds and high velocity jets, respectively. The LVC is by far the most frequent component, with a detection rate of 77%, while only 30% of sources have a HVC. The fraction of HVC detections slightly increases (i.e. 39%) in the sub-sample of stronger accretors (i.e. with log (L acc /L ⊙ )> −3). The [O i]6300Å luminosity of both the LVC and HVC, when detected, correlates with stellar and accretion parameters of the central sources (i.e. L * , M * , L acc ,Ṁ acc ), with similar slopes for the two components. The line luminosity correlates better (i.e. has a lower dispersion) with the accretion luminosity than with the stellar luminosity or stellar mass. We suggest that accretion is the main drivers for the line excitation and that MHD disc-winds are at the origin of both components. In the sub-sample of Lupus sources observed with ALMA a relationship is found between the HVC peak velocity and the outer disc inclination angle, as expected if the HVC traces jets ejected perpendicularly to the disc plane. Mass ejection rates (Ṁ jet ) measured from the detected HVC [O i]6300Å line luminosity span from ∼ 10 −13 to ∼ 10 −7M ⊙ yr −1 . The correspondingṀ jet /Ṁ acc ratio ranges from ∼0.01 to ∼0.5, with an average value of 0.07. However, considering the upper limits on the HVC, we infer aṀ jet /Ṁ acc ratio < 0.03 in more than 40% of sources. We argue that most of these sources might lack the physical conditions needed for an efficient magneto-centrifugal acceleration in the star-disc interaction region. Systematic observations of populations of younger stars, that is, class 0/I, are needed to explore how the frequency and role of jets evolve during the pre-main sequence phase. This will be possible in the near future thanks to space facilities such as the James Webb space telescope (JWST).

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“…More recently, Karska et al (2018) analysed a large sample of low-luminosity Galactic YSOs. All sources exhibit H 2 O emission; 55% of the sources show emission at either 179.5 or 108 µm (see also Karska et al 2013;Mottram et al 2017). The 179.5 µm line accounts for ∼ 8% of the total H 2 O luminosity 9 with a large scatter (Karska et al 2013(Karska et al , 2018.…”

Section: H 2 O Linesmentioning

confidence: 99%

Herschel spectroscopy of massive young stellar objects in the Magellanic Clouds

Oliveira

Loon

Sewiło

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present Herschel Space Observatory Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver Fourier Transform Spectrometer (SPIRE FTS) spectroscopy of a sample of twenty massive Young Stellar Objects (YSOs) in the Large and Small Magellanic Clouds (LMC and SMC). We analyse the brightest farinfrared (far-IR) emission lines, that diagnose the conditions of the heated gas in the YSO envelope and pinpoint their physical origin. We compare the properties of massive Magellanic and Galactic YSOs. We find that [O i] and [C ii] emission, that originates from the photodissociation region associated with the YSOs, is enhanced with respect to the dust continuum in the Magellanic sample. Furthermore the photoelectric heating efficiency is systematically higher for Magellanic YSOs, consistent with reduced grain charge in low metallicity environments. The observed CO emission is likely due to multiple shock components. The gas temperatures, derived from the analysis of CO rotational diagrams, are similar to Galactic estimates. This suggests a common origin to the observed CO excitation, from low-luminosity to massive YSOs, both in the Galaxy and the Magellanic Clouds. Bright far-IR line emission provides a mechanism to cool the YSO environment. We find that, even though [O i], CO and [C ii] are the main line coolants, there is an indication that CO becomes less important at low metallicity, especially for the SMC sources. This is consistent with a reduction in CO abundance in environments where the dust is warmer due to reduced ultraviolet-shielding. Weak H 2 O and OH emission is detected, consistent with a modest role in the energy balance of wider massive YSO environments.

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Outflows, infall and evolution of a sample of embedded low-mass protostars

Cited by 69 publications

References 158 publications

ALMA reveals a large structured disk and nested rotating outflows in DG Tauri B

ALMA reveals a large structured disk and nested rotating outflows in DG Tauri B

Connection between jets, winds and accretion in T Tauri stars

Herschel spectroscopy of massive young stellar objects in the Magellanic Clouds

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