ALMA Observations of SMM11 Reveal an Extremely Young Protostar in Serpens Main Cluster

Aso, Yusuke; Ohashi, Nagayoshi; Aikawa, Yuri; Machida, Masahiro N.; Saigo, Kazuya; Saito, Masao; Takakuwa, Shigehisa; Tomida, Kengo; Tomisaka, Kohji; Yen, Hsi-Wei; Williams, Jonathan P.

doi:10.3847/2041-8213/aa9701

Cited by 13 publications

(15 citation statements)

References 46 publications

(60 reference statements)

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“…Because Class 0 protostars cannot be directly observed at infrared wavelengths, millimeter/submillimeter observations have been developed to investigate them, particularly, interferometric observations at high spatial resolution. These observational studies suggest that circumstellar disks start to form in the Class 0 phase (e.g., Tobin et al 2012;Murillo & Lai 2013;Ohashi et al 2014;Yen et al 2017;Aso et al 2017a), and reveal morphology and kinematics of molecular outflows/jets in Class 0 protostars (e.g., Hirano et al 2006Hirano et al , 2010Yen et al 2017;Lee et al 2017;Aso et al 2017b). Opening angles of protostellar outflows widen on a timescale similar to the lifetime of Class 0 protostars (Arce & Sargent 2006;Machida & Hosokawa 2013) and molecular abundances are predicted, and observed, to vary within the Class 0 phase (Harsono et al 2015;Aikawa et al 2012;Hirano & Liu 2014;Aso et al 2017b).…”

Section: Introductionmentioning

confidence: 90%

“…These observational studies suggest that circumstellar disks start to form in the Class 0 phase (e.g., Tobin et al 2012;Murillo & Lai 2013;Ohashi et al 2014;Yen et al 2017;Aso et al 2017a), and reveal morphology and kinematics of molecular outflows/jets in Class 0 protostars (e.g., Hirano et al 2006Hirano et al , 2010Yen et al 2017;Lee et al 2017;Aso et al 2017b). Opening angles of protostellar outflows widen on a timescale similar to the lifetime of Class 0 protostars (Arce & Sargent 2006;Machida & Hosokawa 2013) and molecular abundances are predicted, and observed, to vary within the Class 0 phase (Harsono et al 2015;Aikawa et al 2012;Hirano & Liu 2014;Aso et al 2017b). These studies suggest that we can distinguish finer levels of evolution within the Class 0 phase than the simple SED classification from optical/infrared observations.…”

Section: Introductionmentioning

confidence: 97%

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The Distinct Evolutionary Nature of Two Class 0 Protostars in Serpens Main SMM4

Aso

Hirano

Aikawa

et al. 2018

ApJ

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We have observed the submillimeter continuum condensation SMM4 in Serpens Main using the Atacama Large Millimeter/submillimeter Array (ALMA) during its Cycle 3 in 1.3 mm continuum, 12 CO J = 2 − 1, SO J N = 6 5 − 5 4 , and C 18 O J = 2−1 lines at angular resolutions of ∼ 0. 55 (240 au). The 1.3 mm continuum emission shows that SMM4 is spatially resolved into two protostars embedded in the same core: SMM4A showing a high brightness temperature, 18 K, with little extended structure and SMM4B showing a low brightness temperature, 2 K, with compact and extended structures. Their separation is ∼ 2100 au. Analysis of the continuum visibilities reveals a disk-like structure with a sharp edge at r ∼ 240 au in SMM4A, and a compact component with a radius of 56 au in SMM4B. The 12 CO emission traces fan-shaped and collimated outflows associated with SMM4A and SMM4B, respectively. The blue and red lobes of the SMM4B outflow have different position angles by ∼ 30 • . Their inclination and bending angles in the 3D space are estimated at i b ∼ 36 • , i r ∼ 70 • , and α ∼ 40 • , respectively. The SO emission traces shocked regions, such as cavity walls of outflows and the vicinity of SMM4B. The C 18 O emission mainly traces an infalling and rotating envelope around SMM4B. The C 18 O fractional abundance in SMM4B is ∼ 50 times smaller than that of the interstellar medium. These results suggest that SMM4A is more evolved than SMM4B. Our studies in Serpens Main demonstrate that continuum and line observations at millimeter wavelengths allow us to differentiate evolutionary phases of protostars within the Class 0 phase.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 97%

The Distinct Evolutionary Nature of Two Class 0 Protostars in Serpens Main SMM4

Aso

Hirano

Aikawa

et al. 2018

ApJ

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“…Pezzuto et al 2012;Gerin et al 2015) or 70 µm dark cores (e.g. Feng et al 2016;Aso et al 2017). It is also quite possible that: i) these jets/knots are part of large flows from distant sources; ii) the driving sources are still embedded in dense cores and are too faint to be detected in the Spitzer and Herschel bands (see Section 5.1 for further discussion).…”

Section: Identification Of the Outflows And Outflow Driving Sourcesmentioning

confidence: 99%

YSO jets in the Galactic plane from UWISH2 – V. Jets and outflows in M17

Samal

Chen

Takami

et al. 2018

Monthly Notices of the Royal Astronomical Society

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Jets and outflows are the first signposts of stellar birth. Emission in the H 2 1-0 S(1) line at 2.122 µm is a powerful tracer of shock excitation in these objects. Here we present the analysis of 2.0 × 0.8 deg 2 data from the UK Widefield Infrared Survey for H 2 (UWISH2) in the 1-0 S(1) line to identify and characterize the outflows of the M17 complex. We uncover 48 probable outflows, of which, 93 per cent are new discoveries. We identified driving source candidates for 60 per cent of the outflows. Among the driving source candidate YSOs: 90 per cent are protostars and the reminder 10 per cent are Class II YSOs. Comparing with results from other surveys, we suggest that H 2 emission fades very quickly as the objects evolve from protostars to premain-sequence stars. We fit SED models to 14 candidate outflow driving sources and conclude that the outflows of our sample are mostly driven by moderate-mass YSOs that are still actively accreting from their protoplanetary disc. We examined the spatial distribution of the outflows with the gas and dust distribution of the complex, and observed that the filamentary dark-cloud "M17SWex" located at the south-western side of the complex, is associated with a greater number of outflows. We find our results corroborate previous suggestions, that in the M17 complex, M17SWex is the most active site of star formation. Several of our newly identified outflow candidates are excellent targets for follow up studies to better understand very early phase of protostellar evolution.

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“…Much has been learned about the bolometric temperatures (Myers & Ladd 1993), luminosities, and lifetimes of the low mass population of these young stellar objects (YSOs) from mostly unresolved far-IR space-based observations (see review by Dunham et al 2014). ALMA observations are now revealing high-resolution details of their envelopes and outflows(e.g., Evans et al 2015;Aso et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Detection of Photospheric Features in the Near-infrared Spectrum of a Class 0 Protostar

Greene¹,

Gully-Santiago²,

Barsony³

2018

ApJ

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We present a near-infrared K-band R 1500 Keck spectrum of S68N, a Class 0 protostar in the Serpens molecular cloud. The spectrum shows a very red continuum, CO absorption bands, weak or non-existent atomic metal absorptions, and H 2 emission lines. The near-IR H 2 emission is consistent with excitation in shocks or by X-rays but not by UV radiation. We model the absorption component as a stellar photosphere plus circumstellar continuum emission with wavelength-dependent extinction. A Markov Chain Monte Carlo analysis shows that the most likely model parameters are consistent with a low-temperature, low-gravity photosphere with significant extinction and no more than modest continuum veiling. Its T eff 3260 K effective temperature is similar to that of older, more evolved pre-main-sequence stars, but its surface gravity log g 2.4 cm s −2 is approximately 1 dex lower. This implies that the radius of this protostar is a factor of ∼ 3 larger than that of 10 6 yr old T Tauri stars. Its low veiling is consistent with a circumstellar disk having intrinsic near-IR emission that is less than or equal to that of more evolved Class I protostars. Along with the high extinction, this suggests that most of the circumstellar material is in a cold envelope, as expected for a Class 0 protostar. This is the first known detection and analysis of a Class 0 protostar absorption spectrum.

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ALMA Observations of SMM11 Reveal an Extremely Young Protostar in Serpens Main Cluster

Cited by 13 publications

References 46 publications

The Distinct Evolutionary Nature of Two Class 0 Protostars in Serpens Main SMM4

The Distinct Evolutionary Nature of Two Class 0 Protostars in Serpens Main SMM4

YSO jets in the Galactic plane from UWISH2 – V. Jets and outflows in M17

Detection of Photospheric Features in the Near-infrared Spectrum of a Class 0 Protostar

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