Transcript of Kotomi Taniguchi (SOKENDAI / NRO) Hiroyuki Ozeki (Toho Univ.), Masao Saito (NRO/SOKENDAI) Fumitaka...
- Slide 1
- Kotomi Taniguchi (SOKENDAI / NRO) Hiroyuki Ozeki (Toho Univ.),
Masao Saito (NRO/SOKENDAI) Fumitaka Nakamura (NAOJ/SOKENDAI), Seiji
Kameno (JAO) Masatoshi Ohishi (NAOJ/SOKENDAI), Tomoya Hirota
(NAOJ/SOKENDAI) Nami Sakai (The Univ. of Tokyo), Satoshi Yamamoto (
The Univ. of Tokyo), Shuro Takano (Nihon Univ.)
- Slide 2
- Introduction Observations Results & Discussion Summary
Future Works
- Slide 3
- Introduction Observations Results & Discussion Summary
Future Works
- Slide 4
- Slide 5
- One of the representative carbon-chain molecules They have been
detected in the interstellar medium since 1970s CH CCC C N
- Slide 6
- (Winstanley & Nejad, 1996) Ion-Molecule Reactions ( t <
10 4 yrs) Neutral-neutral Reactions (t > 10 4 yrs) C n H + C n N
+ HC n N + H 2 C n N + HC n N N H2H2 e-e- H2H2 HCN HC 3 N HC 5 N HC
7 N HC 9 N C2HC2H C n H 2 + CN HC 2n+1 N + H (n = 4,6, and 8)
C2HC2H C2HC2H C2HC2H
- Slide 7
- Toward the Cyanopolyyne Peak (CP) in TMC-1 HC 3 N ( Takano et
al., 1998 ) CCS ( Sakai et al., 2007 ) CCH ( Sakai et al., 2010 ) C
3 S & C 4 H ( Sakai et al., 2013 )
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- Ex. HC 3 N [H 13 CCCN] : [HC 13 CCN] : [HCC 13 CN ] = 1.0 : 1.0
: 1.4 Molecules with two equivalent carbon atoms 13 C-enriched Main
formation pathway C 2 H 2 + CN HC 3 N + H Main formation pathway C
2 H 2 + CN HC 3 N + H
- Slide 9
- HC 4 H + CN HC 5 N + H Exothermic Reaction (Fukuzawa et al.
(1998)) Rapid Reaction k = (4.2 0.2) 10 10 cm 3 mol 1 s 1 (Seki et
al. (1996))
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- Reveal the main formation pathway of HC 5 N in TMC-1 Obtain
perception of the formation mechanism of the longer
cyanopolyynes
- Slide 11
- Introduction Observations Results & Discussion Summary
Future Works
- Slide 12
- (Hirahara et al. (1992)) Cyanopolyyne Peak in TMC-1 ( R.A. =
04h 41m 42s.29, Decl. = 2541 27, J2000) *Distance from the Earth
140 pc *One of the most studied dark clouds *Carbon-chain molecules
are abundant Cyanopolyyne Peak in TMC-1 ( R.A. = 04h 41m 42s.29,
Decl. = 2541 27, J2000) *Distance from the Earth 140 pc *One of the
most studied dark clouds *Carbon-chain molecules are abundant
- Slide 13
- 2013-2014 SEASON2014-2015 SEASON Receiver : Z45 Spectrometer :
SAM45 J = 16-15 (42 GHz region) Integration time (ON) = 27.5 hr
Receiver : H20 Spectrometer : SAM45 J = 9-8 (23 GHz region)
Integration time (ON) = 42.1 hr Normal species and five 13 C
isotopologues of HC 5 N
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- (Yamaki et al. (2002)) On : Off = 20 : 5 [sec] 60-ch smoothing
for the 23 GHz region 32-ch smoothing for the 42 GHz region Applied
smoothing for the off-source spectra
- Slide 15
- Introduction Observations Results & Discussion Summary
Future Works
- Slide 16
- (1 ) H 13 CCCCCN HC 13 CCCCN HCC 13 CCCN HCCC 13 CCN HCCCC 13
CN
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- [H 13 CCCCCN] : [HC 13 CCCCN] : [HCC 13 CCCN] : [HCCC 13 CCN] :
[HCCCC 13 CN] = 1.00 : 0.97 : 1.03 : 1.05 : 1.16 ( 0.19) ( 1 ) [H
13 CCCCCN] : [HC 13 CCCCN] : [HCC 13 CCCN] : [HCCC 13 CCN] : [HCCCC
13 CN] = 1.00 : 0.97 : 1.03 : 1.05 : 1.16 ( 0.19) ( 1 ) No
significant differences in abundances among the five 13 C
isotopologues
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- If HC 5 N is formed by the reactions involving CN HCCCC 13 CN
is more abundant than the other 13 C isotopologues by 1.4 [H 13
CCCN] : [HC 13 CCN] : [HCC 13 CN] = 1.0 : 1.0 : 1.4 (Takano et al.
(1998))
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- Pathways involving CN HC 4 H + CN HC 5 N + H Growth of the
carbon chain of HC 3 N Ex. HC 3 N + C 2 H HC 5 N + H HC 3 N + C 2 H
m + HC 5 N + mH e-e-
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- There is no mechanisms for 13 C concentration of specific
carbon atom All carbon atoms in HC 5 N are originated from C 5 H m
+ All 13 C isotopologues of HC 5 N have almost same abundances
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- Double Isotope Method m, n = 0 - 4
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- The 14 N/ 15 N of HC 3 N is considered to reflect that of CN HC
5 N 363 (31) HC 5 N 363 (31) 15 N is concentrated in CN
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- Assumptions : 14 N/ 15 N elemental ratio = 440 (Solar wind) C
14 N/C 15 N = 195 (HC 3 N) HC 5 N N N CN 31% 59% (16%)
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- Assumptions : 12 C/ 13 C Hydrocarbon ions : CN = 1.0 : 1.4 HC 5
N N N CN 40% 60% (18%) (Takano et al. (1998))
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- HC 5 N N N CN 40% 60% (18%) HC 5 N N N CN 31% 59% (16%) 15 N
Isotopic Fractionation 13 C Isotopic Fractionation Consistent!
- Slide 26
- Introduction Observations Results & Discussion Summary
Future Works
- Slide 27
- We carried out observations of the normal species and the five
13 C isotopologues in TMC-1 We conclude that the main formation
pathways leading to HC 5 N are the reactions of C 5 H m + + N We
have succeeded in the detection of HC 5 15 N in the interstellar
medium for the first time We evaluated the contributions of CN and
N in the formation of HC 5 N, and found out that ~ 40% of HC 5 N is
formed by the reactions involving CN
- Slide 28
- Introduction Observations Results & Discussion Summary
Future Works
- Slide 29
- Green et al. (2014) have been detected HC 5 N towards 35 hot
cores We have carried out observations of HC 5 N, HC 7 N, and other
carbon-chain molecules toward G28.28-0.36
- Slide 30
- Solar wind 440 Solar wind 440 Earth 272 Earth 272 Meteorites,
Comets 100 - 180 When and How 15 N isotopic fractionation does
occur? Our results suggest that concentration of 15 N in CN occur
in the dark cloud stage How is inherited? Taniguchi et al. (ALMA
Proposal)
- Slide 31
- We aim to establish new carbon-chain chemistry in hot cores (My
Doctors thesis) Submitted proposals for GBT and ALMA Through these
studies, I would like to reveal the formation mechanisms of complex
organic molecules Work with Saito-san, Ohishi-san, Hirota-san,
Ozeki-san
- Slide 32
- I thank Prof. Dobashi and Dr. Shimoikura for discussing
calibration of the data of the Z45 receiver. Im grateful for all
NRO Staff and members of Z45 Receiver Group.