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We used the NRAO Very Large Array to search for 3.6 cm continuum emission from embedded protostars in a sample of 8 nearby ``starless'' cores that show spectroscopic evidence for infalling motions in molecular emission lines. We detect a…

天体物理学 · 物理学 2009-11-07 D. W. A. Harvey , D. J. Wilner , J. Di Francesco , C. -W. Lee , P. C. Myers , J. P. Williams

Observations of young stellar objects (YSOs) in centimeter bands can probe the continuum emission from growing dust grains, ionized winds, and magnetospheric activity, which are intimately connected to the evolution of protoplanetary disks…

The collapse of the protostellar envelope results in the growth of the protostar and the development of a protoplanetary disk, playing a critical role during the early stages of star formation. Characterizing the gas infall in the envelope…

太阳与恒星天体物理 · 物理学 2020-03-11 Y. -L. Yang , N. J. Evans , A. Smith , J. -E. Lee , J. J. Tobin , S. Terebey , H. Calcutt , J. K. Jorgensen , J. D. Green , T. L. Bourke

Low-mass stars build a significant fraction of their total mass during short outbursts of enhanced accretion known as FUor and EXor outbursts. FUor objects are characterized by a sudden brightening of ~5 magnitudes at visible wavelengths…

We investigate molecular evolution in a star-forming core that is initially a hydrostatic starless core and collapses to form a low-mass protostar. The results of a one-dimensional radiation-hydrodynamics calculation are adopted as a…

天体物理学 · 物理学 2009-11-13 Yuri Aikawa , Valentine Wakelam , Robin T. Garrod , Eric Herbst

We present Submillimeter Array (SMA) observations of seven massive molecular clumps which are dark in the far-infrared for wavelengths up to 70 $\mu$m. Our 1.3 mm continuum images reveal 44 dense cores, with gas masses ranging from 1.4 to…

星系天体物理 · 物理学 2019-12-11 Shanghuo Li , Qizhou Zhang , Thushara Pillai , Ian W. Stephens , Junzhi Wang , Fei Li

During their infancy, stars are well known to expel matter violently in the form of well-defined, collimated outflows. A fairly unique exception is found in the Orion BN/KL star-forming region where a poorly collimated and somewhat…

星系天体物理 · 物理学 2015-05-20 Luis A. Zapata , Laurent Loinard , Johannes Schmid-Burgk , Luis F. Rodriguez , Paul Ho , Nimesh A. Patel

We present 8--13 micron low resolution spectra (R~100) of 8 low-mass protostellar objects ("proplyds") in the Orion Nebula using the Long Wavelength Spectrometer (LWS) at the W. M. Keck Observatory. All but one of the sources in our sample…

天体物理学 · 物理学 2009-11-11 R. Y. Shuping , Marc Kassis , Mark Morris , Nathan Smith , John Bally

As part of the ALMA Large Program "Early Planet Formation in Embedded Disks" (eDisk), 12CO (2 - 1) was observed towards 19 nearby low-mass protostars. Of these objects, 15 sources are found to show molecular outflow emission. Based on their…

We present the highest-resolution three-dimensional simulation to date of the collapse of an atomic cooling halo in the early Universe. We use the moving-mesh code arepo with the primordial chemistry module introduced in Greif (2014), which…

星系天体物理 · 物理学 2014-12-08 Fernando Becerra , Thomas H. Greif , Volker Springel , Lars Hernquist

We present a study connecting the physical properties of protostellar envelopes to the morphology of the envelope-scale magnetic field. We used the ALMA polarization observations of 61 young prtostars at 0.87 mm on $\sim400-3000$ au scales…

We identify 45 protostellar outflows in CO maps of the Orion A giant molecular cloud from the CARMA-NRO Orion survey. Our sample includes 11 newly detected outflows. We measure the mass and energetics of the outflows, including material at…

We study the prospects for observing H$_2$ emission during the assembly of primordial molecular cloud kernels. The primordial molecular cloud cores, which resemble those at the present epoch, can emerge around $1+z=20$ according to recent…

天体物理学 · 物理学 2009-11-06 Hideyuki Kamaya , Joseph Silk

Aims. Intermediate Mass (IM) stars are an important component of our Galaxy, as they significantly contribute to the interstellar FUV field and, consequently, play an important role in the energy balance of the ISM. Despite their…

太阳与恒星天体物理 · 物理学 2015-05-13 N. Crimier , C. Ceccarelli , B. Lefloch , A. Faure

Starless dense cores eventually collapse dynamically, which forms protostars inside them, and the physical properties of the cores determine the nature of the forming protostars. We report ALMA observations of dust continuum emission and…

We present ALMA observations of protoplanetary disks ("proplyds") in the Orion Nebula Cluster. We imaged 5 individual fields at 856um containing 22 HST-identified proplyds and detected 21 of them. Eight of those disks were detected for the…

Outflows are key indicators of ongoing star formation. We report the discovery of an unanchored forked stream within the propagating path of an extremely young protostellar outflow in the 70 $\mu$m-dark clump G34.74-0.12, based on ALMA 1.3…

We present a model for the evolution of supermassive protostars from their formation at $M_\star \simeq 0.1\,\text{M}_\odot$ until their growth to $M_\star \simeq 10^5\,\text{M}_\odot$. To calculate the initial properties of the object in…

星系天体物理 · 物理学 2018-04-27 Fernando Becerra , Federico Marinacci , Kohei Inayoshi , Volker Bromm , Lars E. Hernquist

On the basis of its low luminosity, its chemical composition, and the absence of a large-scale outflow, the dense core Cha-MMS1 located in the Chamaeleon I molecular cloud was proposed as a first hydrostatic core (FHSC) candidate a decade…

星系天体物理 · 物理学 2020-01-22 L. A. Busch , A. Belloche , S. Cabrit , B. Commercon , P. Hennebelle

We have carried out a survey of optically-selected dark clouds using the bolometer array SCUBA on the James Clerk Maxwell Telescope, at 850 microns wavelength. The survey covers a total of 0.5 square degrees and is unbiased with reference…

天体物理学 · 物理学 2009-11-07 Anja E. Visser , John S. Richer , Claire J. Chandler