The Evolution of Outflow-Envelope Interactions in Low-Mass Protostars

By H. Arce, A. Sargent. 2006

238 citations recorded by the source corpus.

We present multiline and continuum observations of the circumstellar environment within 104 AU of a sample of protostars to investigate how the effects of outflows on their immediate environment change over time. 12CO (1-0) emission probes the high-velocity molecular outflows near the protostars and demonstrates that the outflow opening angle widens as the nascent star evolves. Maps of the 13CO (1-0) and HCO+ (1-0) outflow emission show that protostellar winds erode the circumstellar envelope through the entrainment of the outer envelope gas. The spatial and velocity distribution of the dense circumstellar envelope, as well as its mass, is traced by the C18O (1-0) emission and also displays evolutionary changes. We show that outflows are largely responsible for these changes and propose an empirical model for the evolution of outflow-envelope interactions. In addition, some of the outflows in our sample appear to affect the chemical composition of the surrounding environment, enhancing the HCO+ abundance. Overall, our results confirm that outflows play a major role in the star formation process through their strong physical and chemical impacts on the environments of the young protostars.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/b5a1996b221a3eb5a42bcabc345c1e65fbfd4e18

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In Astronomy and Astrophysics

1. N. Evans II
2. P. Myers
3. P. Caselli
4. Mark R. Krumholz
5. Ralf Klessen
6. Simon Bruderer
7. E. Bergin
8. E. Dishoeck

In Atmospheric Science

1. P. Caselli
2. Simon Bruderer
3. E. Dishoeck
4. E. Bergin
5. P. Myers
6. M. Tafalla
7. N. Evans II
8. J. Jørgensen

In Spectroscopy

1. P. Caselli
2. N. Evans II
3. Simon Bruderer
4. E. Bergin
5. P. Myers
6. E. Dishoeck
7. D. Wilner
8. C. Dullemond

Citations in the corpus

• Water in star-forming regions with Herschel (WISH). II. Evolution of 557 GHz 110-101 emission in low-mass protostars (2012, background): “As the protostellar system evolves, the outflow cavity opens, and the outflow becomes less collimated (e.g., Arce & Sargent 2006).”
• Accretion disks in luminous young stellar objects (2015, background): “…(Arce & Sargent, 2004), L1157, BHR 71, L1527 IRS (Mottram et al., 2013), L1551 IRS 5 (Chou et al., 2014), L1485 IRS (Yen et al., 2014) and compares it to Ṁacc estimated from the outflow mass loss rate (Hogerheijde et al., 1998; Arce & Sargent, 2006; Dunham et al., 2014), the ratio is still > 1.”
• PROSAC: a submillimeter array survey of low-mass protostars - II. The mass evolution of envelopes, disks, and stars from the class 0 through I stages (2009, background): “The models of Visser et al. also include the presenceof an outflow cavity with a growing opening angle through the evolution consistent with observations (e.g., Arce & Sargent,2006).”
• Theory of Star Formation (2007, background): “Mapping of outflows reveals both simple expanding shells, and more complex features such as multiple cavities and bow shock structures that are suggestive of episodic ejection events (Lee et al., 2002); outflow lobes become broader and more irregular over time (Arce & Sar- gent, 2006).”
• NON-IDEAL MHD EFFECTS AND MAGNETIC BRAKING CATASTROPHE IN PROTOSTELLAR DISK FORMATION (2011, background): “…outflow, thought to be primarily the envelope material swept up by a fast wind (Shu et al. 1991; Shang et al. 2006), is observed to have a narrow jet-like appearance along the axis during the early Class 0 phase and the opening angle at the base increases as the YSO ages (Arce & Sargent 2006).”
• PROSAC: A Submillimeter Array Survey of Low-Mass Protostars. I. Overview of Program: Envelopes, Disks, Outflows, and Hot Cores (2007, methodology): “Recently, Arce & Sargent (2006) imaged a sample of nine Class 0, I, and II young stellar objects in the 12CO 1Y0 line observed with the Owens Valley Radio Observatory Millimeter PROSAC: A SUBMILLIMETER ARRAY SURVEY.”
• Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A Grid of 200,000 YSO Model SEDs (2006, background): “…et al. 1993; Chandler et al. 1996; Tamura et al. 1996; Lucas & Roche 1997; Hogerheijde et al. 1998; Velusamy & Langer 1998; Bachiller & Tafalla 1999; Padgett et al. 1999; Beuther & Shepherd 2005; Shepherd 2005; Arce & Goodman 2001; Arce & Sargent 2004, 2006; Arce et al. 2006; Ybarra et al. 2006).”
• THE HERSCHEL ORION PROTOSTAR SURVEY: SPECTRAL ENERGY DISTRIBUTIONS AND FITS USING A GRID OF PROTOSTELLAR MODELS (2016, background): “These trends do not support the notion of increasing cavity size with later evolutionary stage, which would be expected if outflows play a major role in dispersing envelopes (Arce & Sargent 2006).”
• Complex Molecules in the L1157 Molecular Outflow (2008, background): “…clearly demonstrated by multi-molecular line observations reflecting enhanced molecular abundances either in shocks associated with the outflows or in the outflow cavity walls in the protostellar envelopes (e.g., Garay et al. 1998; Bachiller et al. 2001; Arce & Sargent 2006; Jørgensen et al. 2007).”
• The chemical history of molecules in circumstellar disks - I. Ices (2009, background): “Arce & Sargent (2006) found a linear relationship in log-log space between the age of a sample of 17 young stellar objects and their outflow opening angles.”
• THE VLA NASCENT DISK AND MULTIPLICITY SURVEY OF PERSEUS PROTOSTARS (VANDAM). II. MULTIPLICITY OF PROTOSTARS IN THE PERSEUS MOLECULAR CLOUD (2016, background): “There have also been molecular line data for IRAS 03282+3035 (Arce & Sargent 2006; Yen et al. 2015), but a rotation signature is unclear toward this source and Per-emb-18 does not yet have existing observations.”
• EVOLUTIONARY SIGNATURES IN THE FORMATION OF LOW-MASS PROTOSTARS. II. TOWARD RECONCILING MODELS AND OBSERVATIONS (2005, background): “…et al. (2006), who measured θc ∼ 50◦ for the Class 0 very low luminosity object (VeLLO; Di Francesco et al. 2007) L1014 from deep near-infrared imaging, and by Arce & Sargent (2006), who measured θc ∼ 10 − 60◦ for a sample of 6 Class 0/I embedded sources from millimeter interferometer spectroscopy.”