Radio Properties of Young Stellar Objects in the Core of the Serpens South Infrared Dark Cloud

Kern, Nicholas S.; Keown, Jared; Tobin, John J.; Mead, Adrian; Gutermuth, Robert

doi:10.3847/0004-6256/151/2/42

Cited by 12 publications

(28 citation statements)

References 45 publications

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“…We note that several millimeter sources reside in the 4 beam, as observed in Plunkett et al (2018). The high α ff+s found by Kern et al (2016) (∼2-2.3) suggests that thermal dust emission might still contribute to the centimeter emission. As in SerpM-SMM4, we decided to fix α ff+s to 1.1 for this source.…”

Section: Discussionmentioning

confidence: 55%

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Low dust emissivities and radial variations in the envelopes of Class 0 protostars: possible signature of early grain growth

Galametz

Maury

Valdivia

et al. 2019

A&A

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Context. Analyzing the properties of dust and its evolution in the early phases of star formation is crucial to put constraints on the collapse and accretion processes as well as on the pristine properties of planet-forming seeds. Aims. In this paper, we aim to investigate the variations of the dust grain size in the envelopes of the youngest protostars. Methods. We analyzed Plateau de Bure interferometric observations at 1.3 mm and 3.2 mm for 12 Class 0 protostars obtained as part of the CALYPSO survey. We performed our analysis in the visibility domain and derived dust emissivity index (β 1−3mm ) profiles as a function of the envelope radius at 200-2000 au scales.Results. Most of the protostellar envelopes show low dust emissivity indices decreasing toward the central regions. The decreasing trend remains after correction of the (potentially optically thick) central region emission, with surprisingly low β 1−3mm < 1 values across most of the envelope radii of NGC1333-IRAS4A, NGC1333-IRAS4B, SVS13B, and Serpens-SMM4. Conclusions. We discuss the various processes that could explain such low and varying dust emissivity indices at envelope radii 200-2000 au. Our observations of extremely low dust emissivity indices could trace the presence of large (millimeter-size) grains in Class 0 envelopes, in which case our results would point to a radial increase of the dust grain size toward the inner envelope regions. While it is expected that large grains in young protostellar envelopes could be built via grain growth and coagulation, we stress that the typical timescales required to build millimeter grains in current coagulation models are at odds with the youth of our Class 0 protostars. Additional variations in the dust composition could also partly contribute to the low β 1−3mm we observe. We find that the steepness of the β 1−3mm radial gradient depends strongly on the envelope mass, which might favor a scenario in which large grains are built in high-density protostellar disks and transported to the intermediate envelope radii, for example with the help of outflows and winds.

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Section: Discussionmentioning

confidence: 55%

“…temperature, and internal luminosity. For SerpS-MM18, the α ff+s value was derived by Kern et al (2016) from observations at 4.75 and 7.25 GHz. We note that several millimeter sources reside in the 4 beam, as observed in Plunkett et al (2018).…”

Section: Discussionmentioning

confidence: 99%

Low dust emissivities and radial variations in the envelopes of Class 0 protostars: possible signature of early grain growth

Galametz

Maury

Valdivia

et al. 2019

A&A

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“…The brightest source in the JCMT field seen with ALMA is serp45 (Plunkett et al 2018), and we identify the JCMT source with it. This source is also known as CARMA 7 (3 mm; Plunkett et al 2015a) and VLA 12 (Kern et al 2016). This source is a Class 0 protostar with clear evidence for an episodic jet (Plunkett et al 2015b).…”

Section: B16 Serpens South Carma 7: Linear Groupmentioning

confidence: 92%

The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars

Lee

Johnstone

Lee

et al. 2021

ApJ

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We present the four-year survey results of monthly submillimeter monitoring of eight nearby (<500 pc) starforming regions by the JCMT Transient Survey. We apply the Lomb-Scargle Periodogram technique to search for and characterize variability on 295 submillimeter peaks brighter than 0.14 Jy beam −1 , including 22 disk sources (Class II), 83 protostars (Class 0/I), and 190 starless sources. We uncover 18 secular variables, all of them protostars. No single-epoch burst or drop events and no inherently stochastic sources are observed. We classify the secular variables by their timescales into three groups: Periodic, Curved, and Linear. For the Curved and Periodic cases, the detectable fractional amplitude, with respect to mean peak brightness, is ∼4% for sources brighter than ∼0.5 Jy beam −1 . Limiting our sample to only these bright sources, the observed variable fraction is 37% (16 out of 43). Considering source evolution, we find a similar fraction of bright variables for both Class 0 and Class I. Using an empirically motivated conversion from submillimeter variability to variation in mass accretion rate, six sources (7% of our full sample) are predicted to have years-long accretion events during which the excess mass accreted reaches more than 40% above the total quiescently accreted mass: two previously known eruptive Class I sources, V1647 Ori and EC 53 (V371 Ser), and four Class 0 sources, HOPS 356, HOPS 373, HOPS 383, and West 40. Considering the full protostellar ensemble, the importance of episodic accretion on few years timescale is

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“…Estimates of the distance to W40 seem to favor values between 455 and 600 pc (Kolesnik & Iurevich 1983;Shuping et al 2012), which suggests this cloud lies somewhat farther away than the extinction wall of the Aquila Rift. So far, there are no distance measurements to sources in Serpens South, but many authors argue that the region is at the same distance as Serpens Main, and adopt either 260 or 429 pc (e.g., Gutermuth et al 2008;Maury et al 2011;Heiderman & Evans 2015;Plunkett et al 2015;Kern et al 2016). It has also been argued that W40 and Serpens South belong to the same continuous extinction feature and should be part of the same complex, likely at the same distance (Maury et al 2011).…”

Section: Introductionmentioning

confidence: 99%

The Gould’s Belt Distances Survey (Gobelins). Iii. The Distance to the Serpens/Aquila Molecular Complex

Ortiz-León

Dzib

Kounkel

et al. 2017

ApJ

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130

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We report on new distances and proper motions to seven stars across the Serpens/Aquila complex. The observations were obtained as part of the Gould's Belt Distances Survey (GOBELINS) project between 2013 September and 2016 April with the Very Long Baseline Array (VLBA). One of our targets is the proto-Herbig AeBe object EC95, which is a binary system embedded in the Serpens Core. For this system, we combined the GOBELINS observations with previous VLBA data to cover a total period of 8 years, and derive the orbital elements and an updated source distance. The individual distances to sources in the complex are fully consistent with each other, and the mean value corresponds to a distance of 436.0±9.2 pc for the Serpens/W40 complex. Given this new evidence, we argue that Serpens Main, W40, and Serpens South are physically associated and form a single cloud structure.

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Radio Properties of Young Stellar Objects in the Core of the Serpens South Infrared Dark Cloud

Cited by 12 publications

References 45 publications

Low dust emissivities and radial variations in the envelopes of Class 0 protostars: possible signature of early grain growth

Low dust emissivities and radial variations in the envelopes of Class 0 protostars: possible signature of early grain growth

The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars

The Gould’s Belt Distances Survey (Gobelins). Iii. The Distance to the Serpens/Aquila Molecular Complex

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