J/ApJ/897/L38 Protostars excitation temperatures (Van't Hoff+, 2020)
Carbon-grain Sublimation: A New Top-down Component of Protostellar Chemistry.
van't Hoff M.L.R., Bergin E.A., Jorgensen J.K., Blake G.A.
<Astrophys. J., 897, L38 (2020)>
=2020ApJ...897L..38V 2020ApJ...897L..38V
ADC_Keywords: YSOs; Molecular data
Keywords: Astrochemistry ; Protostars
Abstract:
Earth's carbon deficit has been a persistent problem in our
understanding of the formation of our solar system. A possible
solution would be the sublimation of carbon grains at the so-called
soot line (∼300K) early in the planet-formation process. Here, we
argue that the most likely signatures of this process are an excess of
hydrocarbons and nitriles inside the soot line, and a higher
excitation temperature for these molecules compared to oxygen-bearing
complex organics that desorb around the water snowline (∼100K). Such
characteristics have been reported in the literature, for example, in
Orion KL, although not uniformly, potentially due to differences in
the observational settings and analysis methods of different studies
or the episodic nature of protostellar accretion. If this process is
active, this would mean that there is a heretofore unknown component
to the carbon chemistry during the protostellar phase that is acting
from the top down-starting from the destruction of larger
species-instead of from the bottom up from atoms. In the presence of
such a top-down component, the origin of organic molecules needs to be
re-explored.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 130 144 Overview of literature presenting excitation
temperatures for both N- and O-COMs in protostars
refs.dat 61 62 References used
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See also:
J/A+AS/124/205 : W3 star-forming region 345 GHz survey (Helmich+ 1997)
J/A+AS/133/29 : Molecular line survey towards UC HII (Hatchell+ 1998)
J/ApJS/156/127 : 350µm molecular line survey of Orion KL (Comito+, 2005)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/A+A/539/A143 : Nearby B-stars stellar parameters and abundances (Nieva+,2012)
J/A+A/559/A47 : Sgr B2(N) and Sgr B2(M) IRAM 30m line survey (Belloche+, 2013)
J/A+A/568/A65 : NGC 7129 FIRS 2 interferometric 1-D spectrum (Fuente+, 2014)
J/A+A/581/A71 : Orion-KL substructure at 1.3mm (Feng+, 2015)
J/ApJS/232/3 : Spectral line surveys of 30 regions (Widicus Weaver+, 2017)
J/A+A/625/A147 : 80-116GHz spectrum of L483 (Agundez+, 2019)
J/A+A/632/A57 : G328.2551-0.5321 spectra (Csengeri+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Source Source name
24- 32 A9 --- Type Source type; Low, intermediate or high mass
34- 36 I3 K TexN [11/753]? Excitation temperature Nitrogen bearing
complex organic molecule (1)
38- 42 I5 K E_TexN [0/235]? Positive error in TexN (1)
44- 48 I5 K e_TexN [0/235]? Negative error in TexN (1)
50- 52 I3 K TexO [4/599]? Excitation temperature Oxygen bearing
complex organic molecule (2)
54- 58 I5 K E_TexO [0/412]? Positive error in TexO (2)
60- 64 I5 K e_TexO [0/412]? Negative error in TexO (2)
66- 68 I3 K TexCH3CN [9/400]? Excitation temperature CH3CN (3)
70- 74 I5 K E_TexCH3CN [0/60]? Positive error in TexCH3CN
76- 79 I4 K e_TexCH3CN [0/60]? Negative error in TexCH3CN
81- 83 I3 K TexCH3OH [13/305]? Excitation temperature CH3OH (4)
85- 88 I4 K E_TexCH3OH [0/62]? Positive error in TexCH3OH
90- 93 I4 K e_TexCH3OH [0/62]? Negative error in TexCH3OH
95- 97 A3 --- CGS Sign of carbon-grain sublimation (5)
99-117 A19 --- Tel Telescope(s) used for observations
119-120 A2 --- Method Analysis method used; Rotational diagram (RD) or
spectral modeling (M)
122-130 A9 --- Ref Reference(s) used
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Note (1): Highest excitation temperature among all N-bearing COMs in the study.
Note (2): Highest excitation temperature among all O-bearing COMs in the study.
Note (3): Excitation temperature for CH3CN (or isotopologue) if this was not the
highest temperature among the N-bearing COMs.
Note (4): Excitation temperature for CH3OH (or isotopologue) if this was not the
highest temperature among the O-bearing COMs.
Note (5): Sign of carbon-grain sublimation if the excitation temperature for the
N-bearing COM is higher than that of O-bearing COM.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Ref Reference code
6- 26 A21 --- Autor Main autor
28- 46 A19 --- BIB BIBcode
48- 61 A14 --- Cat Catalog reference in Vizier
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 07-Oct-2021