2019/09/06 by Tien-Hao Hsieh, Nadia M. Murillo, Arnaud Belloche +7 · 1 citation
Chemistry · Materials Science · Physics and Astronomy · #Accretion (finance) #Accretion disc #Astrophysics and Star Formation Studies #Fullerene Chemistry and Applications #Luminosity #Polymer Nanocomposite Synthesis and Irradiation #Protostar #Stars #Young stellar object #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/1538-4357/ab425a
22 pages, 15 figures, accepted to ApJ
arxiv created 2019/09/06 · openalex created_date 2019/09/12 · openalex publication_date 2019/10/20 · arxiv updated 2019/11/06 · openalex updated_date 2026/08/06
Abstract Episodic accretion has been used to explain the wide range of protostellar luminosities, but its origin and influence on the star-forming process are not yet fully understood. We present an ALMA survey of N 2 H + (1−0) and HCO + (3−2) toward 39 Class 0 and Class I sources in the Perseus molecular cloud. N 2 H + and HCO + are destroyed via gas-phase reactions with CO and H 2 O, respectively, thus tracing the CO and H 2 O snowline locations. A snowline location at a much larger radius than that expected from the current luminosity suggests that an accretion burst has occurred in the past that has shifted the snowline outward. We identified 18/18 Class 0 and 9/10 Class I post-burst sources from N 2 H + and 7/17 Class 0 and 1/8 Class I post-burst sources from HCO + . The accretion luminosities during the past bursts are found to be ∼10–100 L ⊙ . This result can be interpreted as either evolution of burst frequency or disk evolution. In the former case, assuming that refreeze-out timescales are 1000 yr for H 2 O and 10,000 yr for CO, we found that the intervals between bursts increase from 2400 yr in the Class 0 stage to 8000 yr in the Class I stage. This decrease in the burst frequency may reflect that fragmentation is more likely to occur at an earlier evolutionary stage when the young stellar object is more prone to instability.