Extension of HOPS out to 500 pc (eHOPS). I. Identification and Modeling of Protostars in the Aquila Molecular Clouds

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.We present a Spitzer/Herschel focused survey of the Aquila molecular clouds (d ∼ 436 pc) as part of the eHOPS (extension of the Herschel orion protostar survey, or HOPS, Out to 500 ParSecs) census of nearby protostars. For every source detected in the Herschel/PACS bands, the eHOPS-Aquila catalog contains 1–850 μm SEDs assembled from the Two Micron All Sky Survey, Spitzer, Herschel, the Wide-field Infrared Survey Explorer, and James Clerk Maxwell Telescope/SCUBA-2 data. Using a newly developed set of criteria, we classify objects by their SEDs as protostars, pre-main-sequence stars with disks, and galaxies. A total of 172 protostars are found in Aquila, tightly concentrated in the molecular filaments that thread the clouds. Of these, 71 (42%) are Class 0 protostars, 54 (31%) are Class I protostars, 43 (25%) are flat-spectrum protostars, and four (2%) are Class II sources. Ten of the Class 0 protostars are young PACS bright red sources similar to those discovered in Orion. We compare the SEDs to a grid of radiative transfer models to constrain the luminosities, envelope densities, and envelope masses of the protostars. A comparison of the eHOPS-Aquila to the HOPS protostars in Orion finds that the protostellar luminosity functions in the two star-forming regions are statistically indistinguishable, the bolometric temperatures/envelope masses of eHOPS-Aquila protostars are shifted to cooler temperatures/higher masses, and the eHOPS-Aquila protostars do not show the decline in luminosity with evolution found in Orion. We briefly discuss whether these differences are due to biases between the samples, diverging star formation histories, or the influence of environment on protostellar evolution. © 2023. The Author(s). Published by the American Astronomical Society.R.P., S.T.M., and S.A.F. gratefully acknowledge the funding support for this work from the NASA/ADAP grants 80NSSC18K1564 and 80NSSC20K0454. S.T.M. and R.P. also acknowledge funding support from the NSF AST grant 2107827. R.A.G. acknowledges funding from the NASA/ADAP grant NNX17AF24G and the NSF AST grant 2107705. A.S. gratefully acknowledges support by the Fondecyt Regular (project code 1220610), and ANID BASAL projects ACE210002 and FB210003. M.O. acknowledges support from the MCIN/AEI/10.13039/ 501100011033 through the PID2020-114461GB-I00, and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía, and the European Regional Development Fund from the European Union through the grant P20-00880. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology (Caltech), under a contract with NASA; it is also based on observations made with the Herschel Space Observatory, a European Space Agency Cornerstone Mission with significant participation by NASA. The Herschel spacecraft was designed, built, tested, and launched under a contract to ESA managed by the Herschel/Planck Project team by an industrial consortium under the overall responsibility of the prime contractor Thales Alenia Space (Cannes), and including Astrium (Friedrichshafen) responsible for the payload module and for system testing at the spacecraft level, Thales Alenia Space (Turin) responsible for the service module and Astrium (Toulouse) is responsible for the telescope, with more than 100 subcontractors. The James Clerk Maxwell Telescope is operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan; Academia Sinica Institute of Astronomy and Astrophysics; the Korea Astronomy and Space Science Institute; the National Astronomical Research Institute of Thailand; Center for Astronomical Mega-Science (as well as the National Key R&D Program of China with No. 2017YFA0402700). Additional funding support is provided by the Science and Technology Facilities Council of the United Kingdom and participating universities and organizations in the United Kingdom and Canada. Additional funds for the construction of SCUBA-2 were provided by the Canada Foundation for Innovation. This publication also makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe

Investigating Protostellar Accretion-Driven Outflows Across the Mass Spectrum: JWST NIRSpec IFU 3-5~μ\mum Spectral Mapping of Five Young Protostars

Investigating Protostellar Accretion (IPA) is a Cycle 1 JWST program using the NIRSpec+MIRI IFUs to obtain 2.9--28 $\mu$m spectral cubes of five young protostars with luminosities of 0.2 to 10,000 L$_{\odot}$ in their primary accretion phase. This paper introduces the NIRSpec 2.9--5.3 $\mu$m data of the inner 840-9000 au with spatial resolutions from 28-300 au. The spectra show rising continuum emission, deep ice absorption, emission from H$_{2}$, H~I, and [Fe~II], and the CO fundamental series in emission and absorption. Maps of the continuum emission show scattered light cavities for all five protostars. In the cavities, collimated jets are detected in [Fe~II] for the four $< 320$~L$_{\odot}$ protostars, two of which are additionally traced in Br-$\alpha$. Knots of [Fe~II] emission are detected toward the most luminous protostar, and knots of [FeII] emission with dynamical times of $< 30$~yrs are found in the jets of the others. While only one jet is traced in H$_2$, knots of H$_2$ and CO are detected in the jets of four protostars. H$_2$ is seen extending through the cavities showing they are filled by warm molecular gas. Bright H$_2$ emission is seen along the walls of a single cavity, while in three cavities, narrow shells of H$_2$ emission are found, one of which has an [Fe~II] knot at its apex. These data show cavities containing collimated jets traced in atomic/ionic gas surrounded by warm molecular gas in a wide-angle wind and/or gas accelerated by bow shocks in the jets.Comment: 30 pages, 11 figure

300: An ACA 870 μm Continuum Survey of Orion Protostars and Their Evolution

We present an 870 μ m continuum survey of 300 protostars from the Herschel Orion Protostar Survey using the Atacama Compact Array (ACA). These data measure protostellar flux densities on envelope scales ≤8000 au (20″) and resolve the structure of envelopes with 1600 au (4″) resolution, a factor of 3–5 improvement in angular resolution over existing single-dish 870 μ m observations. We compare the ACA observations to Atacama Large Millimeter/submillimeter Array 12 m array observations at 870 μ m with ∼0.″1 (40 au) resolution. Using the 12 m data to measure the fluxes from disks and the ACA data within 2500 au to measure the combined disk plus envelope fluxes, we calculate the 12 m/ACA 870 μ m flux ratios. Our sample shows a clear evolution in this ratio. Class 0 protostars are mostly envelope-dominated with ratios <0.5. In contrast, Flat Spectrum protostars are primarily disk-dominated with ratios near 1, although with a number of face-on protostars dominated by their envelopes. Class I protostars span the range from envelope to disk-dominated. The increase in ratio is accompanied by a decrease in the envelope fluxes and estimated mass infall rates. We estimate that 80% of the mass is accreted during the envelope-dominated phase. We find that the 12 m/ACA flux ratio is an evolutionary indicator that largely avoids the inclination and foreground extinction dependence of spectral energy distribution-based indicators