Tokyo Univ. of Sciencea

Nobeyama Radio Observatoryb

Shizuoka Univ.c

Sophia Univ.d

○○○○M. Araki,a S. Takano,b H. Yamabe,a

N. Koshikawa,a K. Tsukiyama,a

A. Nakane,c T. Okabayashi,c

A. Kunimatsu,d N. Kuzed

Radio Searches for Interstellar Carbon Chains HC4OH and

H2CCC

I. A Search for the Interstellar Linear Carbon-Chain Alcohol HC4OH in the Star-Forming Region L1527 and the Dark Cloud TMC-1

Radio Searches for Interstellar Carbon Chains HC4OH and

H2CCC

II. Radio Search for H2CCC toward HD183143 as a Candidate of Diffuse Interstellar Band Carrier

1. Introduction

� HC4OH: Candidate of a New Interstellar Molecule � 2007 Sophia Univ. Stark-Modulation MW Spectroscopy� 2010 Shizuoka Univ. FT-MW Spectroscopy

Chemical Composition of Interstellar Space

Interstellar Molecules 163 species*Linear Carbon Chain: 33 speciesAlcohol: MeOH, EtOH, Vinyl Alcohol

Linear Carbon-Chain Alcohol : New Category

→ Search for HC4OH*http://www.rs.kagu.tus.ac.jp/tsukilab/

Low-mass star-forming region L1527

Dark cloud TMC-1

Target clouds• Rich carbon chains

2. Observations

• Rich O bearing molecules

*http://www.rs.kagu.tus.ac.jp/tsukilab/

Observed Molecules in L1527

*http://www.rs.kagu.tus.ac.jp/tsukilab/

25d 41' 27".04h 41m 42.49sTMC-1

26d 03' 11".04h 39m 53.89sL1527

Decl.

(J2000)R.A.

(J2000)

Outdoor sky map 2000

Galactic Plane

The equinoctial

Orion

Taurus

Taurus Dark-Clouds Region

Galactic Longitude [degree]

Gal

acti

c La

titu

de [

degr

ee]

Tokyo Gakugei University, http://darkclouds.u-gakugei.ac.jp/

TMC-1

L1527

Light Extinction

Nobeyama Radio Observatory 45m TelescopeTelescope

1～2 hIntegration TimeSeveral mK in Antenna Temp.Search Deepness

2009/04/11-17 L1527, TMC-12010/01/15-21 L15272011/03/04-05 L1527

Date

Observed Transitions of HC4OH

S40H30H22

6K TMC-1

10K L1527

Ka = 0

High-Resolution Search

Nobeyama Radio Observatory 45m TelescopeTelescope

1～2 hIntegration TimeSeveral mK in Antenna Temp.Search Deepness

2009/04/11-17 L1527, TMC-12010/01/15-21 L15272011/03/04-05 L1527

Date

Observed Lines

38.1NJ = 44 – 33

38.1NJ = 45 – 34C4H

85.7NJ = 99 – 88b

85.6NJ = 910 – 89b

42.6J = 16 – 15 bHC5N

b Sakai et al. 2008, 2009a Kuze et al. in preparation.

GHz

29.8JKa,Kc = 70,7 – 60,6

38.3JKa,Kc = 90,9 – 80,8

42.5JKa,Kc = 100,10 – 90,9

21.3JKa,Kc = 50,5 – 40,4HC4OHa

46.7JKa,Kc = 110,11–100,10

3. Results and Discussion

VLSR(kms-1)

VLSR(kms-1)

TA* (K

)

TMC-1

L1527

21.3

29.8

38.3

42.5

46.7

42.6 GHz

HC4OHNo Detection

42.5

42.6 GHz

38.1

L1527

NRO 45 m 38.9"

Integrated Intensity0.422 Kkms-1

33"0.585 Kkms-1

VLSR(kms-1)

TA* (K

)

HC5N

J = 16-15

42.6 GHz

NRO

GBT 100 m 17.5"Sakai et al. 2009

Distribution of HC4OH in L1527

HC4CN (HC5N) = HC4OH

L1527 TMC-1Column Density/ cm-2

HC4OH <2.0 × 1012 <5.6 × 1012

C4H 1.01 × 1014 2.9 × 1014 *HC5N 6.8 × 1012 * 6.3 × 1013 **

Excitation Temperature/ KHC4OH 12.3 fix(C4H2*) 3.8 fix(C4H2*)

C4H 14.3 6.7 *HC5N 14.7* 6.5**

Upper Limits of HC4OH Column Densities

(Local Thermal Equilibrium), *Sakai et al., 2008&2009, **Takano et al. 1990

3σσσσ noise level

Column Density Ratios

L1527 TMC-1

[HC5N]/ [C4H] 1/15 1/5

[HC4OH]/[HC5N] <0.3 <0.1

[HC4OH]/[C4H] <1/52 <1/52

What is a contribution to chemical reaction from the ratios?

No chemical reactions for HC4OH are reported.

� O/OH reacts with a carbon chain.OX(+) + C4X(+) → XC4OX(+) → HC4OH

� O/OH extends a carbon chain.OX(+) → XC2OX(+) → XC4OX(+) → HC4OH

The HC4OH/C4H ratio can contribute to know the chemical reactions of HC4OH.

Two schemes for Chemical Reactions of HC4OH

4. Summary

� Upper limits of HC4OH < 2.0 × 1012 cm-2

� HC5N > HC4OH� C4H >> HC4OH

Chemical Reactions of HC4OH

� Deep Search of HC4OH in L1527 and TMC-1

II. Radio Search for H2CCC toward HD183143 as a Candidate of Diffuse Interstellar Band Carrier

H

H

C C C

I. A Search for the Interstellar Linear Carbon-Chain Alcohol HC4OH in the Star-Forming Region L1527 and the Dark Cloud TMC-1

Radio Searches for Interstellar Carbon Chains HC4OH and

H2CCC

2015/2/20 22

� Absorption lines by interstellar moleculesDiffuse Interstellar Bands (DIBs)

� First report in 1922� Optical ～NIR (width:1-100 cm-1)� ~600 lines� → No identification so far

Diffuse Interstellar Bands

X

A or B

Absorption

Electronic transition

1. Introduction

Diffuse Interstellar Bands: DIBs

★

X

A

B

forbidden

allowed

Mass selected H2CCC6K Ne-Matrix, Absorption spectra

H2CCC as a Diffuse Interstellar Band Carrier

Maier et al., ApJ, 726, 41 (2011).

H

H

C C C

H2CCC

D2CCC

Cavity Ring Down Spectra

D2CCC

H2CCCH2CCC

+ l-C3H

l-C3H removed

?

Validation: Stanton et al. 2012 Negative ion photoelectron spectroscopy + Theoretical calculations

Jet, High Resolution5450Å 4881Å

Maier et al. 2011

DIBs and Laboratory Spectra

DIBs at 5450 and 4881 ÅAgreements in widths, wavelengths and profiles

Column density：5×1014 cm-2

DIB at 4881 Å DIB at 5450 Å

Maier et al. 2011

Excitation Temperature

Upper state life time100 fs

Diffuse Clouds Temp.: 10-60K

Lab. 60 KMaier et al. (2011)

� Agreements in diffuse peaks� DIBs are not toward the same star.� DIBs are not by the same cloud.� Too much abundances as H2CCC（>>C2）

★

Opinion 1

Oka & McCall, Science, 331, 293 (2011).

Opinion 2

HD183143

Krełowski et al., ApJ, 735, 124 (2011)

Strong variability

Toward 49 stars

H2CCC

blendingH2CCC pure

Blending?

HD183143

H2CCC ?

How to Judge the Identification

� Maier et al. Yes� Oka & McCall No� Krełowski et al. No → blending → ？

Dipole Moments: 4.162 D H2CCC has been detected in dark clouds by radio observations.

Radio observations of H2CCC toward HD183143

Column density: 5×1014 cm-2 (Maier et al. 2011) Excitation temperature: 10 - 60 K JKa,Kc = 51,5–41,4 : 102.99238 GHz

→ Antenna temperature: ~2 K

� The 45 m telescope in Nobeyama Radio Observatory

� Date: 2012 January 15� JKa,Kc = 51,5–41,4 : 102.99238 GHz � Receiver: S100

2. Observations

Integration: 1h25mAntenna Temp.: 32 mK

galactic

plane

HD183143

[α(J2000), δ(J2000)] = (19h 27m 26s.56, 18°17´45.″20)

The 7th magnitude star

HD183143

Two diffuse clouds

toward HD183143

Velocity: 7.7 and 23.6 km s−1

CH 4300Å

McCall et al., ApJ, 567, 391, (2002)★

HD183143

CH

CH

Linewidths (FWHM): 7.7 and 4.9 km s−1

Components by Frequency Throw

Possible line profile of H2CCC

Arb

itra

ry I

nten

sity

3. Results and Discussions

Integration: 1h25mAntenna Temp.: 32 mK

40

60

3σ= 95 mK

Upper limit of column densities H2CCC

Ortho + Para23.6 kms-1 + 7.7 kms-1

10 K 1.1 × 1013 cm−2

60 K 2.0 ×××× 1013 cm−−−−2

Upper limit of column density

� Ortho/Para = 3.0 � Permanent dipole moment = 4.162 D � Excitation temp. = 10 - 60 K � Column density ratio = 40:60 (CH) � Velocity of 23.6 km s−1

3σ rms noise = 95 mK � Linewidth of 4.9 km s−1 (CH)

Toward HD183143

25

1<

The huge column density (5×1014 cm-2, Maier et al. 2011) of H2CCC toward HD183143 was unjustified.

Å

DIB at 5450 Å

The upper limit of a column density is 2.0 ×1013 cm−2.

blendingH2CCC pure

How about toward other stars?

HD183143

The major carrier of DIBs at 5450 and 4881 Å can not be H2CCC. Assumption: HD183143 has a normal column density for H2CCC.

4. Summary

� We searched for the rotational transition of H2CCC at 103 GHz toward HD183143 using the 45 m telescope at NRO.

� The upper limit of a column density toward HD183143 is 2.0 × 1013 cm−2.

� The huge column density of H2CCC toward HD183143 (Maier et al. 2011) was unjustified.

� The major carrier of DIBs at 5450 and 4881 Åcan not be H2CCC.

H

H

C C C