The Herschel Orion Protostar Survey: Luminosity and Envelope Evolution

DOI: 
10.3847/1538-4357/aa6d69
Publication date: 
01/05/2017
Main author: 
Fischer, William J.
IAA authors: 
Osorio, Mayra
Authors: 
Fischer, William J.;Megeath, S. Thomas;Furlan, Elise;Ali, Babar;Stutz, Amelia M.;Tobin, John J.;Osorio, Mayra;Stanke, Thomas;Manoj, P.;Poteet, Charles A.;Booker, Joseph J.;Hartmann, Lee;Wilson, Thomas L.;Myers, Philip C.;Watson, Dan M.
Journal: 
The Astrophysical Journal
Refereed: 
Yes
Publication type: 
Article
Volume: 
840
Pages: 
69
Abstract: 

The Herschel Orion Protostar Survey obtained well-sampled 1.2─870 μm spectral energy distributions (SEDs) of over 300 protostars in the Orion molecular clouds, home to most of the young stellar objects (YSOs) in the nearest 500 pc. We plot the bolometric luminosities and temperatures for 330 Orion YSOs, 315 of which have bolometric temperatures characteristic of protostars. The histogram of the bolometric temperature is roughly flat; 29% of the protostars are in Class 0. The median luminosity decreases by a factor of four with increasing bolometric temperature; consequently, the Class 0 protostars are systematically brighter than the Class I protostars, with a median luminosity of 2.3 {L}<SUB>ȯ </SUB> as opposed to 0.87 {L}<SUB>ȯ </SUB>. At a given bolometric temperature, the scatter in luminosities is three orders of magnitude. Using fits to the SEDs, we analyze how the luminosities corrected for inclination and foreground reddening relate to the mass in the inner 2500 au of the best-fit model envelopes. The histogram of the envelope mass is roughly flat, while the median-corrected luminosity peaks at 15 {L}<SUB>ȯ </SUB> for young envelopes and falls to 1.7 {L}<SUB>ȯ </SUB> for late-stage protostars with remnant envelopes. The spread in luminosity at each envelope mass is three orders of magnitude. Envelope masses that decline exponentially with time explain the flat mass histogram and the decrease in luminosity, while the formation of a range of stellar masses explains the dispersion in luminosity.

Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019934090&doi=10.3847%2f1538-4357%2faa6d69&partnerID=40&md5=694b17f27e719faa5fccc81d7b43a26a
ADS Bibcode: 
2017ApJ...840...69F
Keywords: 
circumstellar matter;infrared: stars;stars: formation;stars: protostars;Astrophysics - Solar and Stellar Astrophysics;Astrophysics - Astrophysics of Galaxies