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

DOI: 
10.3847/1538-4357/ac9f4b
Publication date: 
15/02/2023
Main author: 
Federman, Samuel
IAA authors: 
Osorio, Mayra
Authors: 
Federman, Samuel;Megeath, S. Thomas;Tobin, John J.;Sheehan, Patrick D.;Pokhrel, Riwaj;Habel, Nolan;Stutz, Amelia M.;Fischer, William J.;Hartmann, Lee;Stanke, Thomas;Narang, Mayank;Osorio, Mayra;Atnagulov, Prabhani;Rahatgaonkar, Rohan
Journal: 
The Astrophysical Journal
Publication type: 
Article
Volume: 
944
Pages: 
49
Abstract: 
We present an 870 μm 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 μm observations. We compare the ACA observations to Atacama Large Millimeter/submillimeter Array 12 m array observations at 870 μm 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 μm 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.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023ApJ...944...49F/abstract
ADS Bibcode: 
2023ApJ...944...49F
Keywords: 
Protostars;Young stellar objects;Star formation;1302;1834;1569;Astrophysics - Solar and Stellar Astrophysics;Astrophysics - Astrophysics of Galaxies