Astrochemical Diagnostics of the Isolated Massive Protostar G28.20-0.05
Journal article, 2024
We study the astrochemical diagnostics of the isolated massive protostar G28.20-0.05. We analyze data from Atacama Large Millimeter/submillimeter Array 1.3 mm observations with a resolution of 0.″2 (∼1000 au). We detect emission from a wealth of species, including oxygen-bearing (e.g., H2CO, CH3OH, CH3OCH3), sulfur-bearing (SO2, H2S), and nitrogen-bearing (e.g., HNCO, NH2CHO, C2H3CN, C2H5CN) molecules. We discuss their spatial distributions, physical conditions, correlation between different species, and possible chemical origins. In the central region near the protostar, we identify three hot molecular cores (HMCs). HMC1 is part of a millimeter continuum ring-like structure, is closest in projection to the protostar, has the highest temperature of ∼300 K, and shows the most line-rich spectra. HMC2 is on the other side of the ring, has a temperature of ∼250 K, and is of intermediate chemical complexity. HMC3 is further away, ∼3000 au in projection, cooler (∼70 K), and is the least line-rich. The three HMCs have similar mass surface densities (∼10 g cm−2), number densities (n H ∼ 109 cm−3), and masses of a few solar masses. The total gas mass in the cores and in the region out to 3000 au is ∼25 M ⊙, which is comparable to that of the central protostar. Based on spatial distributions of peak line intensities as a function of excitation energy, we infer that the HMCs are externally heated by the protostar. We estimate column densities and abundances of the detected species and discuss the implications for hot core astrochemistry.
Author
Prasanta Gorai
University of Gothenburg
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Chi Yan Law
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
European Southern Observatory (ESO)
Jonathan Tan
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
University of Virginia
Yichen Zhang
Shanghai Jiao Tong University
University of Virginia
Rubén Fedriani
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Institute of Astrophysics of Andalusia (IAA)
Kei E.I. Tanaka
Tokyo Institute of Technology
Mélisse Bonfand
University of Virginia
Giuliana Cosentino
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Diego Mardones
University of Chile (UCH)
Maria T. Beltrán
Arcetri Astrophysical Observatory
G. Garay
University of Chile (UCH)
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 960 2 127Star formation history of MAssive pRoTostars (SMART)
European Commission (EC) (EC/H2020/101032092), 2021-04-01 -- 2023-03-31.
Subject Categories
Meteorology and Atmospheric Sciences
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.3847/1538-4357/ad09bb