2001A&A...367..652F


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST21:06:02

2001A&A...367..652F - Astronomy and Astrophysics, volume 367, 652-673 (2001/2-4)

Low-excitation atomic gas around evolved stars. I. ISO observations of C-rich nebulae.

FONG D., MEIXNER M., CASTRO-CARRIZO A., BUJARRABAL V., LATTER W.B., TIELENS A.G.G.M., KELLY D.M. and SUTTON E.C.

Abstract (from CDS):

We present ISO LWS and SWS spectra of far-infrared (FIR) atomic fine structure lines in 12 carbon-rich evolved stars including asymptotic giant branch (AGB) stars, proto-planetary nebulae (PPNe) and planetary nebulae (PNe). The spectra include grating and Fabry-Perot measurements of the line emission of [OI], [CII], [SiI], [SiII], [SI], [FeI], [FeII], [NeII] and [NII]. Only 5 out of our 12 object sample have been detected in at least one of these FIR lines. When we include the 12 oxygen-rich evolved stars from Castro-Carrizo et al. (2001A&A...367..674C, Paper II), we find that atomic line emission is observed only in those sources in which the central star's Teff≥10000K. Above this cutoff, the number of detectable lines and the intensity of the line emission increase as Teff increases. These trends suggest that the atomic lines originate from photodissociation regions (PDRs). In general, the kinematics of the atomic gas, derived from line fits to the Fabry-Perot data, are comparable to the molecular expansion velocities. These kinematics are expected for atomic cooling lines associated with circumstellar PDRs. AFGL618, however, appears exceptional with dual velocity components: a narrow component (<20km/s) that may be associated with a PDR, and a broad component (∼66km/s) that may be produced in post-shocked, accelerated gas. A new PDR code which properly treats enhanced carbon abundances was used to model the observations of our carbon-rich objects. The predicted line intensities agree reasonably well with the observations. Shock models, however, do not compare well with the observed line intensities. PDR mass estimates ranging from ∼0.01-0.2M were derived from the [CII] 158µm line emission. The atomic gas constitutes only a small fraction of the total mass for young planetary nebulae, but its importance grows significantly as the nebulae evolve. Our overall analysis shows that photodissociation, and not shocks, dominates the evolution of the circumstellar envelope by transforming the initially molecular asymptotic giant branch envelopes into the atomic gas found in proto-planetary and planetary nebulae.

Abstract Copyright:

Journal keyword(s): atomic data - stars: AGB and post-AGB - stars: circumstellar matter - stars: mass-loss - ISM: planetary nebulae

Simbad objects: 33

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Number of rows : 33

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * omi Cet Mi* 02 19 20.79210 -02 58 39.4956   7.63 6.53 5.03   M5-9IIIe+DA 1434 0
2 RAFGL 618 pA* 04 42 53.6245215366 +36 06 53.397219192   16.32   12.59   C-rich 954 0
3 IC 418 PN 05 27 28.2060343141 -12 41 50.282659007   9.78 13.0     O7fp 1000 2
4 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 716 0
5 NGC 2023 RNe 05 41 37.9 -02 15 52           ~ 570 1
6 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1464 0
7 HD 44179 pA* 06 19 58.2185496 -10 38 14.706068 9.51 9.33 9.02     B9Ib/II 715 0
8 NGC 2346 PN 07 09 22.5216571385 -00 48 23.611157830   11.76 11.58     A5V 552 0
9 HD 56126 pA* 07 16 10.2589670319 +09 59 47.953674864   9.20 8.32     F0/5Ia 303 0
10 V* U Mon RV* 07 30 47.4734611972 -09 46 36.788534824 8.22 7.00 5.82     G8/K0Ib/II 193 0
11 OH 231.8 +4.2 OH* 07 42 16.947 -14 42 50.20           M10III+A 503 1
12 IRAS 09371+1212 pA* 09 39 53.96 +11 58 52.6           K7II/III 156 0
13 IRC +10216 C* 09 47 57.40632 +13 16 43.5648     10.96     C9,5e 2133 0
14 WOS 48 C* 15 23 05.0744336371 -51 25 58.881494593   17.85 16.66 14.51 10.18 C 118 1
15 PN Mz 3 PN 16 17 13.3911453558 -51 59 10.706640574   10.8 14.00     O9.5 333 0
16 PN M 2-9 PN 17 05 37.952 -10 08 34.58   12.59 14.7     Be 500 0
17 NGC 6302 PN 17 13 44.339 -37 06 10.95   7.1 10.10     ~ 756 1
18 HD 161796 pA* 17 44 55.4696 +50 02 39.484 8.00 7.68 7.21 6.77 6.51 F3Ib 310 0
19 * 89 Her pA* 17 55 25.1884459710 +26 02 59.970100296 5.36 5.70 5.36 5.06 4.94 F2Ibp 386 0
20 V* AC Her pA* 18 30 16.2374666779 +21 52 00.618442618 8.00 7.79 7.01     F4Ibp 316 0
21 OH 26.5 +0.6 OH* 18 37 32.50920 -05 23 59.1936           ~ 284 0
22 V* R Sct RV* 18 47 28.9509385830 -05 42 18.537825839 8.30 6.67 5.20 4.14 3.37 K4/5pec 295 0
23 M 57 PN 18 53 35.0969571234 +33 01 44.883146221   15.405 15.769 15.901 16.062 DA(O?) 790 2
24 HD 179821 pA* 19 13 58.6083165753 +00 07 31.934676028 10.81 9.694 8.19     G4_0-Ia 221 0
25 HD 184738 PN 19 34 45.2337512278 +30 30 58.951476338   10.41 10.44     [WC9] 919 0
26 Min 1-92 pA* 19 36 18.9292148675 +29 32 49.838032394 12.13 12.35 11.75 11.54   B0.5IV[e] 236 1
27 HD 187885 pA* 19 52 52.7031438648 -17 01 50.293465852   9.25 8.68 8.32   F2/6Ia 170 0
28 V* V1610 Cyg pA* 21 02 18.27 +36 41 37.0           F5Iae 830 1
29 NGC 7027 PN 21 07 01.8 +42 14 10   9.1 10.9     ~ 2322 1
30 [D75b] Em* 21-021 PN 21 29 58.4712776885 +51 04 00.323547316   15.66 14.20 13.89   O7(f)/[WC11] 227 0
31 HD 235858 pA* 22 29 10.3755939027 +54 51 06.341145584   11.40 9.52 8.47 7.34 G5Ia 235 0
32 PN Hb 12 PN 23 26 14.8207203464 +58 10 54.538636094   13.51 11.49 12.44   Oe 313 0
33 IRC +40540 C* 23 34 27.5215563443 +43 33 01.299562617     15.12     C8,3.5eJ 170 0

    Equat.    Gal    SGal    Ecl

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2020.07.04-21:06:02

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