J/ApJ/688/L83 Detection of C5N- in IRC +10216 (Cernicharo+, 2008)
Detection of C5N- and vibrationally excited C6H in IRC +10216.
Cernicharo J., Guelin M., Agundez M., McCarthy M.C., Thaddeus P.
<Astrophys. J., 688, L83-L86 (2008)>
=2008ApJ...688L..83C 2008ApJ...688L..83C
ADC_Keywords: Interstellar medium ; Radio lines ; Stars, carbon
Keywords: circumstellar matter - ISM: molecules - radio lines: ISM -
stars: AGB and post-AGB - stars: individual (IRC+10216)
Abstract:
We report the detection in the envelope of the C-rich star IRC+10216
of four series of lines with harmonically related frequencies: B1389,
B1390, B1394, and B1401. The four series must arise from linear
molecules with mass and size close to those of C6H and C5N. Three
of the series have half-integer rotational quantum numbers; we assign
them to the 2Δ and 2Σ- vibronic states of C6H in
its lowest (ν11) bending mode. The fourth series, B1389, has
integer J with no evidence of fine or hyperfine structure; it has a
rotational constant of 1388.860(2)MHz and a centrifugal distortion
constant of 33(1)Hz; it is almost certainly the C5N- anion.
Description:
The astronomical observations presented here are mainly from a
spectral line survey of IRC+10216 done with the IRAM 30m telescope
between 1995 and 2008 (Cernicharo et al. 2000, Cat. J/A+AS/142/181; J.
Cernicharo et al. 2008, in preparation).
Objects:
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RA (2000) DE Designation(s)
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09 47 57.4 +13 16 44 IRC+10216 = V* CW Leo
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 71 54 Observed line parameters in IRC+10216
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See also:
J/A+AS/142/181 : 2mm molecular line survey of IRC+10 216 (Cernicharo+, 2000)
J/ApJS/177/275 : 1.3 and 2mm survey of IRC+10216 (He+, 2008)
J/ApJS/190/348 : 1mm spectral survey of IRC+10216 + VY CMa (Tenenbaum+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Line Line identification (1)
18- 28 A11 --- Trans Transition
30- 37 F8.1 MHz Freq Observed frequency
39- 41 F3.1 MHz e_Freq The 1σ uncertainty in Freq
43- 50 F8.1 MHz CFreq Calculated frequency
52- 55 F4.2 K.km/s Temp Integrated antenna temperature (2)
57- 60 F4.2 K.km/s e_Temp The 1σ uncertainty in Temp
62- 65 F4.1 km/s Vexp Line width parameter
67- 69 F3.1 km/s e_Vexp ? The 1σ uncertainty in Vexp
71 A1 --- f_Vexp [a] Indicates Vexp has been fixed
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Note (1): Derived rotational constants following table 2:
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Series B(MHz) D(Hz) Nlines J-Range
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B1389 1388.860±0.002 33±1 13 8, 29-40
B1390 1389.878±0.007 -35±3 9 59/2-79/2
B1394 1394.609±0.010 32±4 22 29-41
B1401 1401.559±0.026 139±7 7 59/2-75/2
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See section 3 for further details.
Note (2): Corrected for atmospheric absorption and rear spillover losses,
by means of the ATM code (Cernicharo 1985, ATM: A Program to Compute
Atmospheric Opacity between 0-1000GHz, IRAM Internal Report).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 13-Jan-2011