J/A+A/310/893 C2 Phillips and CN Red bands in HD 56126 (Bakker+, 1996)
Detection of C2, CN, and NaID absorption in the AGB remnant of HD 56126
Bakker E.J., Waters L.B.F.M., Lamers H.J.G.L.M., Trams N.R.,
van der Wolf F.L.A.
<Astron. Astrophys. 310, 893 (1996)>
=1996A&A...310..893B 1996A&A...310..893B (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Equivalent widths
Keywords: molecular processes - circumstellar matter -
stars: individual: HD 56126 - stars: AGB and post-AGB
Description:
We present the detection of molecular absorption lines in the optical
spectrum of the post-AGB star HD 56126. The C2 Phillips
A1{PI}u-X1{SIGMA}+g(1,0), (2,0), and (3,0); Swan
d3{PI}g-a3{PI}u(0,0) and (1,0); and CN Red system
A2{PI}-X2{SIGMA}+ (1,0), (2,0), (3,0), and (4,0) bands have been
identified. From the identification of the molecular bands we find an
expansion velocity of 8.5±0.6km/s independent of excitation
condition or molecular specie. On the basis of the expansion velocity,
rotational temperatures, and molecular column densities we argue that
the line-forming region is the AGB remnant. This is in agreement with
the expansion velocity derived from the CO lines. We find column
densities of logNC2=15.3±0.3cm-2 and
logNCN=15.5±0.3cm-2, and rotational temperatures of
Trot=242±20K and Trot=24±5K respectively for C2 and CN. By
studying molecular line absorption in optical spectra of post-AGB
stars we have found a new tracer of the AGB remnant. From comparison
with the results of CO and IR observations it is possible to obtain
information on non-spherical behavior of the AGB remnant. Using
different molecules with different excitation conditions it should be
possible to study the AGB remnant as a function of the distance to the
star, and thus as a function of the evolutionary status of the star on
the AGB.
Objects:
----------------------------------------------------------------------
RA (2000) DE Name
----------------------------------------------------------------------
07 16 10.2 +09 59 48 HD 56126
----------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table13 84 55 (1,0) C2 Phillips band
table14 83 55 (2,0) C2 Phillips band
table15 82 55 (3,0) C2 Phillips band
table16 72 30 (1,0) CN Red band
table17 77 31 (2,0) CN Red band
table18 82 34 (3,0) CN Red band
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table13 table14 table15
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- B(J'') Line identification
9- 17 F9.3 0.1nm LabLambda Laboratory wavelength in air
21- 28 F8.2 0.1nm ObsLambda ? Observed wavelength
33- 36 F4.1 0.1pm Wlambda ? Observed equivalent width
40- 44 F5.2 --- f(J'J'')10+4 Oscillator strength
49- 53 F5.1 10+12cm-2 N(J'') ? Column density
57- 86 A30 --- Rem Remarks
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table16 table17 table18
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- B Line identification, branch name
10- 12 A3 --- J'' Rotational quantum number, total angular
momentum including spin (1)
16 I1 --- N'' Rotational quantum number, total angular
momentum excluding spin (1)
20- 27 F8.3 0.1nm LabLambda Laboratory wavelength of transition in air
31- 37 F7.2 0.1nm ObsLambda ? Observed wavelength
38 A1 --- n_ObsLambda b=blend, N=NO
39- 43 F5.1 0.1pm W ? Observed equivalent width
48- 53 F6.4 --- f(J'J'')10+4 Oscillator strength
55- 59 F5.1 10+12cm-2 N(N''J'') ? Column density
62- 81 A20 --- Rem Remarks
--------------------------------------------------------------------------------
Note (1): Herzberg G., 1950 "Molecular spectra and molecular structure. I.
Spectra of Diatomic molecules.", second edition.
For CN, N''=J''±1/2
--------------------------------------------------------------------------------
(End) Patricia Bauer [CDS] 23-Mar-1996