Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties

Dunham, Michael M.; Arce, Héctor G.; Mardones, Diego; Lee, Jeong Eun; Matthews, Brenda C.; Stutz, Amelia M.; Williams, Jonathan P.

doi:10.1088/0004-637x/783/1/29

Cited by 118 publications

(204 citation statements)

References 235 publications

(352 reference statements)

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“…The inferred value is consistent with the estimates presented by Dunham et al (2014, M lobe ≥ 4 × 10 −4 M ) and Yıldız et al (2015, M lobe 3 × 10 −4 M ), and it is small when compared to other Class 0 sources (see e.g. Cabrit & Bertout 1992;Wu et al 2004;Curtis et al 2010;Dunham et al 2014;Bjerkeli et al 2013, where estimates typically are higher than 10 −4 M ). The outflow mass is also very small compared to the protostellar mass, which has been estimated at 4 × 10 −2 M (Oya et al 2014).…”

Section: Physical Properties Of the Outflowing Gassupporting

confidence: 91%

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A young bipolar outflow from IRAS 15398-3359

Bjerkeli

Jørgensen

Brinch³

2016

A&A

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Context. Changing physical conditions in the vicinity of protostars allow for a rich and interesting chemistry to occur. Heating and cooling of the gas allows molecules to be released from and frozen out on dust grains. These changes in physics, traced by chemistry as well as the kinematical information, allows us to distinguish between different scenarios describing the infall of matter and the launching of molecular outflows and jets. Aims. We aim to determine the spatial distribution of different species that are of different chemical origin. This is to examine the physical processes in play in the observed region. From the kinematical information of the emission lines we aim to determine the nature of the infalling and outflowing gas in the system. We also aim to determine the physical properties of the outflow. Methods. Maps from the Submillimeter Array (SMA) reveal the spatial distribution of the gaseous emission towards IRAS 15398-3359. The line radiative transfer code LIME is used to construct a full 3D model of the system taking all relevant components and scales into account. Results. CO, HCO + , and N 2 H + are detected and shown to trace the motions of the outflow. For CO, the circumstellar envelope and the surrounding cloud also have a profound impact on the observed line profiles. N 2 H + is detected in the outflow, but is suppressed towards the central region, perhaps because of the competing reaction between CO and H + 3 in the densest regions as well as the destruction of N 2 H + by CO. N 2 D + is detected in a ridge south-west of the protostellar condensation and is not associated with the outflow. The morphology and kinematics of the CO emission suggests that the source is younger than ∼1000 years. The mass, momentum, momentum rate, mechanical luminosity, kinetic energy, and mass-loss rate are also all estimated to be low. A full 3D radiative transfer model of the system can explain all the kinematical and morphological features in the system.

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Section: Physical Properties Of the Outflowing Gassupporting

confidence: 91%

“…Wu et al 2004;Curtis et al 2010;Dunham et al 2014), the values presented here fall at the lower end. In those papers, mass-loss rates are typically reported to be higher than 10 −9 M yr −1 and the mechanical luminosity is for the bulk part of observed outflows higher than 10 −3 L .…”

Section: Physical Properties Of the Outflowing Gasmentioning

confidence: 43%

A young bipolar outflow from IRAS 15398-3359

Bjerkeli

Jørgensen

Brinch³

2016

A&A

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“…The resulting outflow mass is 0.07M e . 7 Comparing to recent surveys of outflows driven by low-mass protostars in the nearby (d < 500 pc) Gould Belt clouds (e.g., Curtis et al 2010;Dunham et al 2014), the LF outflow is within but near the top end of the range of measured outflow masses (10 −3 to a few tenths of a M e ). Thus this detection, at 6.08 kpc, is consistent with an outflow driven by a low-mass protostar, and suggests an outflow near the top end of the mass scale for these types of regions.…”

Section: Cygnus X-3 Little Friend's Outflows/jetsmentioning

confidence: 76%

“…In order to compare the outflow driven by the LF, located at a distance of 6.08 kpc, with those driven by typical low-mass protostars in nearby (d < 500 pc) Gould Belt clouds, we use the 12 CO data to calculate the mass of the LF outflow. We assume optically thin, LTE emission at an excitation temperature of 50K (Dunham et al 2014), and follow the procedures outlined in Dunham et al (2014; see their Appendix C) to convert from brightness temperature to total outflow mass. The resulting outflow mass is 0.07M e .…”

Section: Cygnus X-3 Little Friend's Outflows/jetsmentioning

confidence: 99%

Cygnus X-3: Its Little Friend’s Counterpart, the Distance to Cygnus X-3, and Outflows/Jets

McCollough

Corrales

Dunham

2016

ApJ

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Chandra observations have revealed a feature within 16″ of Cygnus X-3 that varied in phase with Cygnus X-3. This feature was shown to be a Bok globule that is along the line of sight to Cygnus X-3. We report on observations made with the Submillimeter Array to search for molecular emission from this globule, also known as Cygnus X-3ʼs "Little Friend." We have found a counterpart in both 12 CO (2-1) and 13 CO (2-1) emission. From the velocity shift of the molecular lines we are able to find two probable distances based on the Bayesian model of Milky Way kinematics of Reid et al. For the LF velocity of −47.5 km s −1 , we find distances of 6.1±0.6 kpc (62% probability) and 7.8±0.6 kpc (38% probability). This yields distances to Cyg X-3 of 7.4±1.1 kpc and 10.2±1.2 kpc, respectively. Based on the probabilities entailed, we take 7.4±1.1 kpc as the preferred distance to Cyg X-3. We also report the discovery of bipolar molecular outflow, suggesting that there is active star formation occurring within the Little Friend.

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“…While jets and outflows from protostars have been studied using several different tracers and at various wavelengths (e.g., Bally et al 2007;Frank et al 2014), the observational tool that is most often used for the largest sample of protostars is the low-J (  J up 3) CO lines at (sub-)millimeterwavelengths,-which trace the ambient molecular gas swept up and accelerated by the protostellar jets (e.g., Bachiller & Tafalla 1999;Richer et al 2000;Arce et al 2007;Hatchell et al 2007a;Takahashi et al 2008;Curtis et al 2010;Dunham et al 2014a;Plunkett et al 2015). These observations of molecular outflows from protostars have shown that the timeaveraged flow energetic parameters, viz., the mechanical luminosity (L mech ) and the momentum flux or outflow force (F CO ), are correlated with the bolometric luminosity of the protostar, L bol  (Rodriguez et al 1982;Bally & Lada 1983;Lada 1985;Snell 1987;Cabrit & Bertout 1992;Bontemps et al 1996;Wu et al 2004;Hatchell et al 2007a;Takahashi et al 2008;Curtis et al 2010).…”

Section: Introductionmentioning

confidence: 99%

The Evolution of Far-Infrared Co Emission From Protostars

Manoj

Green

Megeath

et al. 2016

ApJ

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We investigate the evolution of far-IR CO emission from protostars observed with Herschel/PACS for 50 sources from the combined sample of HOPS and DIGIT Herschel key programs. From the uniformly sampled spectral energy distributions, whose peaks are well sampled, we computed the L bol , T bol ,and L L bol smm for these sources to search for correlations between far-IR CO emission and protostellar properties. We find a strong and tight correlation between far-IR CO luminosity (L CO fir ) and the bolometric luminosity (L bol ) of the protostars with µ L L CO fir bol 0.7 . We, however, do not find a strong correlation between L CO fir and protostellar evolutionary indicators, T bol and L L bol smm . FIRCO emission from protostars traces the currently shocked gas by jets/outflows, and far-IR CO luminosity, L CO fir , is proportional to the instantaneous mass-loss rate,Ṁ out . The correlation between L CO fir and L bol , then, is indicative of instantaneousṀ out tracking instantaneousṀ acc . The lack of acorrelation between L CO fir and evolutionary indicators T bol and L L bol smm suggests thatṀ out and, therefore,Ṁ acc do not show any clear evolutionary trend. These results are consistent with mass accretion/ejection in protostars being episodic. Taken together with the previous finding that the time-averaged mass-ejection/accretion rate declines during the protostellar phase, our results suggest that the instantaneous accretion/ejection rate of protostars is highly time variable and episodic, but the amplitude and/or frequency of this variability decreases with time such that the timeaveraged accretion/ejection rate declines with system age.

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Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties

Cited by 118 publications

References 235 publications

A young bipolar outflow from IRAS 15398-3359

A young bipolar outflow from IRAS 15398-3359

Cygnus X-3: Its Little Friend’s Counterpart, the Distance to Cygnus X-3, and Outflows/Jets

The Evolution of Far-Infrared Co Emission From Protostars

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