27 research outputs found
Outflows, envelopes, and disks as evolutionary indicators in Lupus YSOs
By studying 7 objects in the Lupus clouds we aim to test if a coherence exists between commonly used evolutionary tracers. We present ALMA observations of the continuum and molecular line emission that probe the dense gas and dust of cores and their associated molecular outflows. Our source selection in a common environment allows for a consistent comparison across different evolutionary stages. The quality of the ALMA molecular data allows us to reveal the nature of the molecular outflows by studying their morphology and kinematics. The images in IRAS15398-3359 appear to show that it drives a precessing episodic jet-driven outflow with at least 4 ejections separated by periods of time between 50 and 80 years, while data in IRAS16059-3857 show similarities with a wide-angle wind model also showing signs of being episodic. The outflow of J160115-41523 could be better explain with the wide-angle wind model as well, but new observations are needed to explore its nature. We find that the most common evolutionary tracers are useful for broad evolutionary classifications, but are not consistent with each other to provide enough granularity to disentangle different evolutionary stage of sources that belong to the same Class. Outflow properties used as protostellar age tracers (mass, momentum, energy, opening angle) may suffer from differences in the nature of each outflow, thus detailed observations are needed to refine evolutionary classifications. We found both AzTEC-lup1-2 and AzTEC-lup3-5 to be in the pre-stellar stage, although the latter could be more evolved. IRAS15398-3359, IRAS16059-3857 and J160115-41523, which have clearly detected outflows, are Class 0 sources, although we are not able to determine which is younger and which is older. Sz102 and Merin28 are the most evolved sources and show signs of having associated flows, not as well traced by CO as for the younger sources.Fil: Vazzano, María Mercedes. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Plunkett, Adele. National Radio Astronomy Observatory; Estados UnidosFil: de Gregorio Monsalvo, Itziar. European Southern Observatory Chile.; ChileFil: Santamaría Miranda, Alejandro. European Southern Observatory Chile.; ChileFil: Takahashi, Satoko. Joint Alma Observatory; ChileFil: Lopez, Cristian. Joint Alma Observatory; Chil
Early Planet Formation in Embedded Disks (eDisk). VIII. A Small Protostellar Disk around the Extremely Low-Mass and Young Class 0 Protostar, IRAS 15398-3359
Protostellar disks are a ubiquitous part of the star formation process and
the future sites of planet formation. As part of the Early Planet Formation in
Embedded Disks (eDisk) large program, we present high-angular resolution dust
continuum (mas) and molecular line (mas) observations of
the Class 0 protostar, IRAS 15398-3359. The dust continuum is small, compact,
and centrally peaked, while more extended dust structures are found in the
outflow directions. We perform a 2D Gaussian fitting to find the deconvolved
size and radius of the dust disk to be
and , respectively. We estimate the gas+dust disk mass
assuming optically thin continuum emission to be ,
indicating a very low-mass disk. The CO isotopologues trace components of the
outflows and inner envelope, while SO traces a compact, rotating disk-like
component. Using several rotation curve fittings on the PV diagram of the SO
emission, the lower limits of the protostellar mass and gas disk radius are
and from our Modified 2 single power-law
fitting. A conservative upper limit of the protostellar mass is inferred to be
. The protostellar mass-accretion rate and the specific angular
momentum at the protostellar disk edge are found to be between
and
, respectively, with an age
estimated between yr. At this young age with no clear
substructures in the disk, planet formation would likely not yet have started.
This study highlights the importance of high-resolution observations and
systematic fitting procedures when deriving dynamical properties of deeply
embedded Class 0 protostars.Comment: 28 pages, 16 figures. Accepted for publication in ApJ as one of the
first-look papers of the eDisk ALMA Large Progra
Early Planet Formation in Embedded Disks (eDisk) V: Possible Annular Substructure in a Circumstellar Disk in the Ced110 IRS4 System
We have observed the Class 0/I protostellar system Ced110 IRS4 at an angular
resolution of (10 au) as a part of the ALMA large program; Early
Planet Formation in the Embedded Disks (eDisk). The 1.3 mm dust continuum
emission reveals that Ced110 IRS4 is a binary system with a projected
separation of 250 au. The continuum emissions associated with the main
source and its companion, named Ced110 IRS4A and IRS4B respectively, exhibit
disk-like shapes and likely arise from dust disks around the protostars. The
continuum emission of Ced110 IRS4A has a radius of 110 au (),
and shows bumps along its major axis with an asymmetry. The bumps can be
interpreted as an shallow, ring-like structure at a radius of 40 au
() in the continuum emission, as demonstrated from two-dimensional
intensity distribution models. A rotation curve analysis on the CO and
CO -1 lines reveals the presence of a Keplerian disk within a
radius of 120 au around Ced110 IRS4A, which supports the interpretation that
the dust continuum emission arises from a disk. The ring-like structure in the
dust continuum emission might indicate a possible, annular substructure in the
surface density of the embedded disk, although the possibility that it is an
apparent structure due to the optically thick continuum emission cannot be
ruled out.Comment: 32 pages, 23 figures. Accepted for publication in ApJ as one of the
first-look papers of the eDisk ALMA Large Progra
Early Planet Formation in Embedded Disks (eDisk) XII: Accretion streamers, protoplanetary disk, and outflow in the Class I source Oph IRS63
We present ALMA observations of the Class I source Oph IRS63 in the context
of the Early Planet Formation in Embedded Disks (eDisk) large program. Our ALMA
observations of Oph IRS63 show a myriad of protostellar features, such as a
shell-like bipolar outflow (in CO), an extended rotating envelope
structure (in CO), a streamer connecting the envelope to the disk (in
CO), and several small-scale spiral structures seen towards the edge of
the dust continuum (in SO). By analyzing the velocity pattern of CO and
CO, we measure a protostellar mass of ~ and confirm the presence of a disk rotating at almost Keplerian
velocity that extends up to au. These calculations also show that the
gaseous disk is about four times larger than the dust disk, which could
indicate dust evolution and radial drift. Furthermore, we model the CO
streamer and SO spiral structures as features originating from an infalling
rotating structure that continuously feeds the young protostellar disk. We
compute an envelope-to-disk mass infall rate of ~ and compare it to the disk-to-star mass accretion rate of ~, from which we infer that the protostellar
disk is in a mass build-up phase. At the current mass infall rate, we speculate
that soon the disk will become too massive to be gravitationally stable.Comment: 26 pages and 17 figure
Early Planet Formation in Embedded Disks (eDisk) III: A first high-resolution view of sub-mm continuum and molecular line emission toward the Class 0 protostar L1527 IRS
Studying the physical and chemical conditions of young embedded disks is
crucial to constrain the initial conditions for planet formation. Here, we
present Atacama Large Millimeter/submillimeter Array (ALMA) observations of
dust continuum at 0.06" (8 au) resolution and molecular line emission at
0.17" (24 au) resolution toward the Class 0 protostar L1527 IRS from the
Large Program eDisk (Early Planet Formation in Embedded Disks). The continuum
emission is smooth without substructures, but asymmetric along both the major
and minor axes of the disk as previously observed. The detected lines of
CO, CO, CO, HCO, c-CH, SO, SiO, and DCN trace
different components of the protostellar system, with a disk wind potentially
visible in CO. The CO brightness temperature and the HCO line
ratio confirm that the disk is too warm for CO freeze out, with the snowline
located at 350 au in the envelope. Both molecules show potential evidence
of a temperature increase around the disk-envelope interface. SO seems to
originate predominantly in UV-irradiated regions such as the disk surface and
the outflow cavity walls rather than at the disk-envelope interface as
previously suggested. Finally, the continuum asymmetry along the minor axis is
consistent with the inclination derived from the large-scale (100" or 14,000
au) outflow, but opposite to that based on the molecular jet and envelope
emission, suggesting a misalignment in the system. Overall, these results
highlight the importance of observing multiple molecular species in multiple
transitions to characterize the physical and chemical environment of young
disks.Comment: 27 pages, 16 figures, 2 tables, 10 pages appendix with 12 figures.
Accepted for publication in ApJ as one of the first-look papers of the eDisk
ALMA Large Progra
Early Planet Formation in Embedded Disks (eDisk). IV. The Ringed and Warped Structure of the Disk around the Class I Protostar L1489 IRS
Constraining the physical and chemical structure of young embedded disks is
crucial to understanding the earliest stages of planet formation. As part of
the Early Planet Formation in Embedded Disks Atacama Large
Millimeter/submillimeter Array Large Program, we present high spatial
resolution (0.\!\!^{\prime\prime}1 or 15 au) observations of the
1.3 mm continuum and CO 2-1, CO 2-1, and SO
- molecular lines toward the disk around the Class I protostar L1489
IRS. The continuum emission shows a ring-like structure at 56 au from the
central protostar and a tenuous, optically thin emission extending beyond
300 au. The CO emission traces the warm disk surface, while the
CO emission originates from near the disk midplane. The coincidence of
the radial emission peak of CO with the dust ring may indicate a
gap-ring structure in the gaseous disk as well. The SO emission shows a highly
complex distribution, including a compact, prominent component at 30
au, which is likely to originate from thermally sublimated SO molecules. The
compact SO emission also shows a velocity gradient along a slightly
() tilted direction with respect to the major axis of the dust
disk, which we interpret as an inner warped disk in addition to the warp around
200 au suggested by previous work. These warped structures may be formed
by a planet or companion with an inclined orbit, or by a gradual change in the
angular momentum axis during gas infall.Comment: 24 pages, 12 figures. Accepted for publication in The Astrophysical
Journal as one of the first-look papers of the eDisk ALMA Large Progra
Early Planet Formation in Embedded Disks (eDisk). I. Overview of the Program and First Results
We present an overview of the Large Program, ``Early Planet Formation in
Embedded Disks (eDisk)'', conducted with the Atacama Large
Millimeter/submillimeter Array (ALMA). The ubiquitous detections of
substructures, particularly rings and gaps, in protoplanetary disks around T
Tauri stars raise the possibility that at least some planet formation may have
already started during the embedded stages of star formation. In order to
address exactly how and when planet formation is initiated, the program focuses
on searching for substructures in disks around 12 Class 0 and 7 Class I
protostars in nearby (200 pc) star-forming regions through 1.3 mm continuum
observations at a resolution of au (0.04"). The initial results show
that the continuum emission, mostly arising from dust disks around the sample
protostars, has relatively few distinctive substructures, such as rings and
spirals, in marked contrast to Class II disks. The dramatic difference may
suggest that substructures quickly develop in disks when the systems evolve
from protostars to Class II sources or alternatively that high optical depth of
the continuum emission could obscure internal structures. Kinematic information
obtained through CO isotopologue lines and other lines reveals the presence of
Keplerian disks around protostars, providing us with crucial physical
parameters, in particular, the dynamical mass of the central protostars. We
describe the background of the eDisk program, the sample selection and their
ALMA observations, the data reduction, and also highlight representative
first-look results.Comment: This is a publication of a series of eDisk ALMA large program
first-look paper
Caracterización del uso de los recursos hidrobiológicos y pesqueros, carne de monte, productos maderables y no maderables en el complejo ventana piloto de humedales Paz de Ariporo-Hato Corozal
Este documento es resultado de la ejecución del Contrato 14-13-014-237PS entre el Instituto Humboldt y la Fundación Omacha, firmado en el marco del Convenio 005 (13-014) entre el Instituto Humboldt y el Fondo Adaptación. Contiene la caracterización del uso de los recursos hidrobiológicos y pesqueros, carne de monte, productos maderables y no maderables en el Complejo de Humedales de Paz de Ariporo-Hato Corozal.BogotáSubdirección de Servicios Científicos y Proyectos Especiale
Identificación de amenazas presentes y potenciales para la conservación de hábitats y especies en el complejo ventana piloto de humedales Paz de Ariporo- Hato Corozal
Este documento es resultado de la ejecución del Contrato 14-13-014-237PS entre el Instituto Humboldt y la Fundación Omacha, firmado en el marco del Convenio 005 (13-014) entre el Instituto Humboldt y el Fondo Adaptación. Contiene la identificación de amenazas presentes y potenciales para la conservación de hábitats y especies en el complejo ventana piloto de humedales de Paz de Ariporo- Hato Corozal.BogotáSubdirección de Servicios Científicos y Proyectos Especiale