In:
The Astrophysical Journal, American Astronomical Society, Vol. 948, No. 2 ( 2023-05-01), p. 127-
Abstract:
We have observed the low-mass protostellar source IRAS 15398−3359 at a resolution of 0.″2–0.″3, as part of the Atacama Large Millimeter/Submillimeter Array Large Program FAUST, to examine the presence of a hot corino in the vicinity of the protostar. We detect nine CH 3 OH lines including the high-excitation lines with upper-state energies up to 500 K. The CH 3 OH rotational temperature and the column density are derived to be 119 − 26 + 20 K and 3.2 − 1.0 + 2.5 × 10 18 cm −2 , respectively. The beam filling factor is derived to be 0.018 − 0.003 + 0.005 , indicating that the emitting region of CH 3 OH is much smaller than the synthesized beam size and is not resolved. The emitting region of three high-excitation lines, 18 3,15 –18 2,16 , A ( E u = 447 K), 19 3,16 –19 2,17 , A ( E u = 491 K), and 20 3,17 –20 2,18 , A ( E u = 537 K), is located within the 50 au area around the protostar and seems to have a slight extension toward the northwest. Toward the continuum peak, we also detect one emission line from CH 2 DOH and two features of multiple CH 3 OCHO lines. These results, in combination with previous reports, indicate that IRAS 15398−3359 is a source with hybrid properties showing both hot corino chemistry rich in complex organic molecules on small scales (∼10 au) and warm carbon-chain chemistry rich in carbon-chain species on large scales (∼100–1000 au). A possible implication of the small emitting region is further discussed in relation to the origin of the hot corino activity.
Type of Medium:
Online Resource
ISSN:
0004-637X
,
1538-4357
DOI:
10.3847/1538-4357/acc1e5
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2023
detail.hit.zdb_id:
2207648-7
detail.hit.zdb_id:
1473835-1
SSG:
16,12
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