High-resolution ammonia mapping of the very young protostellar core Chamaeleon-MMS1

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Väisälä, M.S.
dc.contributor.author Harju, J.
dc.contributor.author Mantere, M.J.
dc.contributor.author Miettinen, O.
dc.contributor.author Sault, R.S.
dc.contributor.author Walmsley, C.M.
dc.contributor.author Whiteoak, J.B.
dc.date.accessioned 2018-08-01T13:35:58Z
dc.date.available 2018-08-01T13:35:58Z
dc.date.issued 2014
dc.identifier.citation Väisälä , M S , Harju , J , Mantere , M J , Miettinen , O , Sault , R S , Walmsley , C M & Whiteoak , J B 2014 , ' High-resolution ammonia mapping of the very young protostellar core Chamaeleon-MMS1 ' ASTRONOMY AND ASTROPHYSICS , vol 564 , A99 . DOI: 10.1051/0004-6361/201322069 en
dc.identifier.issn 0004-6361
dc.identifier.issn 1432-0746
dc.identifier.other PURE UUID: e5bd5534-15fe-4095-a6c4-d0b3f46ae93b
dc.identifier.other PURE ITEMURL: https://research.aalto.fi/en/publications/highresolution-ammonia-mapping-of-the-very-young-protostellar-core-chamaeleonmms1(e5bd5534-15fe-4095-a6c4-d0b3f46ae93b).html
dc.identifier.other PURE LINK: http://dx.doi.org/10.1051/0004-6361/201322069
dc.identifier.other PURE FILEURL: https://research.aalto.fi/files/26502190/aa22069_13.pdf
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/32946
dc.description VK: resolve; Karhunen, J.; ReSoLVE
dc.description.abstract Aims. The aim of this study is to investigate the structure and kinematics of the nearby candidate first hydrostatic core Cha-MMS1. Methods. Cha-MMS1 was mapped in the NH3(1,1) line and the 1.2 cm continuum using the Australia Telescope Compact Array (ATCA). The angular resolution of the ATCA observations is 7″ (~1000 AU), and the velocity resolution is 50 m s-1. The core was also mapped with the 64 m Parkes Telescope in the NH3(1,1) and (2,2) lines. Observations from Herschel Space Observatory and Spitzer Space Telescope were used to help interpretation. The ammonia spectra were analysed using Gaussian fits to the hyperfine structure. A two-layer model was applied in the central parts of the core where the ATCA spectra show signs of self-absorption. Results. A compact high column density core with a steep velocity gradient (~20 km s-1 pc-1) is detected in ammonia. We derive a high gas density (~106 cm-3) in this region, and a fractional ammonia abundance compatible with determinations towards other dense cores (~10-8). This suggests that the age of the high density core is comparable to the freeze-out timescale of ammonia in these conditions, on the order of 104 years. The direction of the velocity gradient agrees with previous single-dish observations, and the overall velocity distribution can be interpreted as rotation. The rotation axis goes through the position of a compact far-infrared source detected by Spitzer and Herschel. The specific angular momentum of the core, ~10-3km s-1 pc, is typical for protostellar envelopes. A string of 1.2 cm continuum sources is tentatively detected near the rotation axis. The ammonia spectra suggest the presence of warm embedded gas in its vicinity. An hourglass-shaped structure is seen in ammonia at the cloud’s average LSR velocity, also aligned with the rotation axis. Although this structure resembles a pair of outflow lobes the ammonia spectra show no indications of shocked gas. Conclusions. The observed ammonia structure mainly delineates the inner envelope around the central source. The velocity gradient is likely to originate in the angular momentum of the contracting core, although influence of the outflow from the neighbouring young star IRS4 is possibly visible on one side of the core. The tentative continuum detection and the indications of a warm background component near the rotation axis suggest that the core contains a deeply embedded outflow which may have been missed in previous single-dish CO surveys owing to beam dilution. en
dc.format.extent 15
dc.format.mimetype application/pdf
dc.language.iso en en
dc.relation.ispartofseries ASTRONOMY AND ASTROPHYSICS en
dc.relation.ispartofseries Volume 564 en
dc.rights openAccess en
dc.title High-resolution ammonia mapping of the very young protostellar core Chamaeleon-MMS1 en
dc.type A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä fi
dc.description.version Peer reviewed en
dc.contributor.department Centre of Excellence Research on Solar Long-Term Variability and Effects, ReSoLVE
dc.identifier.urn URN:NBN:fi:aalto-201808014347
dc.identifier.doi 10.1051/0004-6361/201322069
dc.type.version publishedVersion

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