Outflow forces in intermediate-mass star formation

Kempen, T. A. van; Hogerheijde, M. R.; Dishoeck, E. F. van; Kristensen, L. E.; Беллоче, А.; Klaassen, Pamela; Leurini, S.; José-García, I. San; Aykutalp, Aycin; Choi, Yunhee; Endo, Akira; Frieswijk, W.; Harsono, Daniel; Karska, A.; Koumpia, E.; Marel, Nienke van der; Nagy, Z.; Pérez-Beaupuits, J. P.; Risacher, C.; Weeren, R. J. van; Wyrowski, F.; Yıldız, U. A.; Güsten, R.; Boland, W.; Baryshev, A.

doi:10.1051/0004-6361/201424725

Cited by 19 publications

(11 citation statements)

References 61 publications

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“…If we estimate the mechanical force for the outflow F CO , we obtain a value of 1.5 × 10 −5 M yr −1 km s −1 . This value is low compared from those obtained for intermediate-mass young stars reported in Table 7 of van Kempen et al (2016), again suggesting that this outflow is associated with a low-mass or in the limit of an intermediate star. If we add the momentum and energy from the optical counterpart could be an intermediate-mass star.…”

Section: N2d+(3−2)contrasting

confidence: 59%

ALMA Observations of the Extraordinary Carina Pillars: HH 901/902

Cortes-Rangel¹,

Zapata²,

Toalá³

et al. 2020

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We present Atacama Large Millimeter/Submillimeter Array (ALMA) 1.3 mm continuum and C 18 O(2−1), N 2 D + (3−2), 13 CS(5−4), and 12 CO(2−1) line sensitive and high angular resolution (∼0.3 ) observations of the famous carina pillars and protostellar objects HH 901/902. Our observations reveal for the first time, the bipolar CO outflows and the dusty disks (plus envelopes) that are energizing the extended and irradiated HH objects far from the pillars. We find that the masses of the disks+envelopes are about 0.1 M and of the bipolar outflows are between 10 −3 -10 −4 M , which suggests that they could be low-or maybe intermediate-mass protostars. Moreover, we suggest that these young low-mass stars are likely embedded Class 0/I protostars with high-accretion rates. We also show the kinematics of the gas in the pillars together with their respective gas masses (0.1 -0.2 M ). We estimate that the pillars will be photo-evaporated in 10 4 to 10 5 years by the massive and luminous stars located in the Trumpler 14 cluster. Finally, given the short photo-evaporated timescales and that the protostars in these pillars are still very embedded, we suggest that the disks inside of the pillars will be quickly affected by the radiation of the massive stars, forming proplyds, like those observed in Orion.

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Section: N2d+(3−2)contrasting

confidence: 59%

ALMA Observations of the Extraordinary Carina Pillars: HH 901/902

Cortes-Rangel¹,

Zapata²,

Toalá³

et al. 2020

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“…Observations of high-J CO and SiO suggest that excitation conditions change at higher velocities, with density and gas temperature rapidly rising (Nisini et al 2007;Lefloch et al 2015;Kristensen et al 2017). The assumed temperature here is 75 K, which is reasonable for a slow wing (Yıldız et al 2015;van Kempen et al 2016). However, if the jet has different excitation conditions with higher temperatures, the CO mass of the gas will be underestimated.…”

Section: Jet and Wind Kinematics What Is Driving The Outflows?mentioning

confidence: 99%

Chemical and kinematic structure of extremely high-velocity molecular jets in the Serpens Main star-forming region

Tychoniec

Hull

Kristensen

et al. 2019

A&A

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Context. Outflows are one of the first signposts of ongoing star formation. The fastest molecular component to the protostellar outflows -extremely high-velocity (EHV) molecular jets -are still puzzling since they are seen only rarely. As they originate deep inside the embedded protostar-disk system, they provide vital information about the outflow-launching process in the earliest stages. Aims. The first aim is to analyze the interaction between the EHV jet and the slow outflow by comparing their outflow force content. The second aim is to analyze the chemical composition of the different outflow velocity components and to reveal the spatial location of molecules. Methods. ALMA 3 mm (Band 3) and 1.3 mm (Band 6) observations of five outflow sources at 0 . 3 -0 . 6 (130 -260 au) resolution in the Serpens Main cloud are presented. Observations of CO, SiO, H 2 CO and HCN reveal the kinematic and chemical structure of those flows. Three velocity components are distinguished: the slow and the fast wing, and the EHV jet. Results. Out of five sources, three have the EHV component. Comparison of outflow forces reveals that only the EHV jet in the youngest source Ser-emb 8 (N) has enough momentum to power the slow outflow. The SiO abundance is generally enhanced with velocity, while HCN is present in the slow and the fast wing, but disappears in the EHV jet. For Ser-emb 8 (N), HCN and SiO show a bow-shock shaped structure surrounding one of the EHV peaks suggesting sideways ejection creating secondary shocks upon interaction with the surroundings. Also, the SiO abundance in the EHV gas decreases with distance from this protostar, whereas that in the fast wing increases. H 2 CO is mostly associated with low-velocity gas but also appears surprisingly in one of the bullets in the Ser-emb 8 (N) EHV jet. No complex organic molecules are found to be associated with the outflows. Conclusions. The high detection rate suggests that the presence of the EHV jet may be more common than previously expected. The EHV jet alone does not contain enough outflow force to explain the entirety of the outflowing gas. The origin and temporal evolution of the abundances of SiO, HCN and H 2 CO through high-temperature chemistry are discussed. The data are consistent with a low C/O ratio in the EHV gas versus high C/O ratio in the fast and slow wings.

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“…More recently, van Kempen et al (2016) used APEX to study a sample of six IM protostars, mapping the bipolar outflows and quiescent gas in 12 CO and 13 CO J=6 -5 and finding that their line luminosities and outflow forces also follow trends with bolometric luminosity and outflow mass, connecting low-and high-mass protostars, however they could not confirm the result of Beltrán et al (2008) that fragmentation enhances outflow forces for IM protostars in clusters. Studying one of the largest samples thus far, Crimier et al (2010) determined the physical structure of the envelopes of a sample of five IM protostars via radiative-transfer modelling, finding that the physical parameters describing the envelopes vary smoothly between low-and high-mass protostars, and that the density structure was consistent with predictions from the predictions of "inside-out" collapse.…”

Section: Introductionmentioning

confidence: 99%

“…IM protostars -the precursors of Herbig Ae/Be stars -are defined as young stellar objects (YSOs) that will reach final masses of 2-8 M and have luminosities between ∼50-2000 L (Beltrán 2015). The lower limit of 2 M originates from the fact that above this limit stars should not have the outer convective zones required to produce the magnetic fields needed for magnetically-mediated accretion (see Simon et al 2002, for an observational confirmation of this temperature and thus mass limit); the upper limit of 8 M originates from the stellar mass required to produce a type II supernova, which is used to define the lower mass limit for high-mass stars (Zinnecker & Yorke 2007). The upper mass limit also corresponds to the mass above which photo-ionization by UV E-mail: py11gb@leeds.ac.uk photons becomes easily observable in cm continuum and the mass above which a pre-main sequence phase is not observable (Beltrán & de Wit 2016).…”

Section: Introductionmentioning

confidence: 99%

Connecting low- and high-mass star formation: the intermediate-mass protostar IRAS 05373+2349 VLA 2

Brown¹,

Johnston²,

Hoare³

et al. 2016

Mon. Not. R. Astron. Soc.

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Until recently, there have been few studies of the protostellar evolution of intermediatemass (IM) stars, which may bridge the low-and high-mass regimes. This paper aims to investigate whether the properties of an IM protostar within the IRAS 05373+2349 embedded cluster are similar to that of low-and/or high-mass protostars. We carried out Very Large Array as well as Combined Array for Research in Millimeter Astronomy continuum and 12 CO(J=1-0) observations, which uncover seven radio continuum sources (VLA 1-7). The spectral index of VLA 2, associated with the IM protostar is consistent with an ionised stellar wind or jet. The source VLA 3 is coincident with previously observed H 2 emission line objects aligned in the north-south direction (P.A. -20 to -12• ), which may be either an ionised jet emanating from VLA 2 or (shock-)ionised cavity walls in the large-scale outflow from VLA 2. The position angle between VLA 2 and 3 is slightly misaligned with the large-scale outflow we map at ∼5-arcsec resolution in 12 CO (P.A. ∼30• ), which in the case of a jet suggests precession. The emission from the mm core associated with VLA 2 is also detected; we estimate its mass to be 12-23 M , depending on the contribution from ionised gas. Furthermore, the largescale outflow has properties intermediate between outflows from low-and high-mass young stars. Therefore, we conclude that the IM protostar within IRAS 05373+2349 is phenomenologically as well as quantitatively intermediate between the low-and high-mass domains.

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Outflow forces in intermediate-mass star formation

Cited by 19 publications

References 61 publications

ALMA Observations of the Extraordinary Carina Pillars: HH 901/902

ALMA Observations of the Extraordinary Carina Pillars: HH 901/902

Chemical and kinematic structure of extremely high-velocity molecular jets in the Serpens Main star-forming region

Connecting low- and high-mass star formation: the intermediate-mass protostar IRAS 05373+2349 VLA 2

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