The Herschel Orion Protostar Survey: Luminosity and Envelope Evolution

Journal Article · Wed May 10 00:00:00 UTC 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA6D69· OSTI ID:22872735

Fischer, William J.; Poteet, Charles A. ^[1]; Megeath, S. Thomas; Booker, Joseph J. ^[2]; Furlan, Elise ^[3]; Ali, Babar ^[4]; Stutz, Amelia M. ^[5]; Tobin, John J. ^[6]; Osorio, Mayra ^[7]; Stanke, Thomas ^[8]; Manoj, P. ^[9]; Hartmann, Lee ^[10]; Wilson, Thomas L. ^[11]; Myers, Philip C. ^[12]

---

1. Space Telescope Science Institute, Baltimore, MD (United States)
2. Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States)
3. IPAC, California Institute of Technology, Pasadena, CA (United States)
4. Space Science Institute, Boulder, CO (United States)
5. Max-Planck-Institut für Astronomie, Heidelberg (Germany)
6. Leiden Observatory, Leiden University, Leiden (Netherlands)
7. Instituto de Astrofísica de Andalucía, CSIC, Granada (Spain)
8. European Southern Observatory, Garching bei München (Germany)
9. Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai (India)
10. Department of Astronomy, University of Michigan, Ann Arbor, MI (United States)
11. National Science Foundation, Arlington, VA (United States)
12. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

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 ⊙} as opposed to 0.87 L{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 ⊙} for young envelopes and falls to 1.7 L{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.

• OSTI ID: 22872735
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 840; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BOLOMETERS
DISPERSIONS
ENERGY SPECTRA
INCLINATION
INFRARED RADIATION
LUMINOSITY
MASS
PROTOSTARS
STAR EVOLUTION
STARS