From the AGB to the PN phase with the PdBI

From the AGB to the PN phase with the Plateau de Bure

Interferometer

Arancha Castro-CarrizoJan Martin Winters

Roberto Neri

Institut de Radio Astronomie Millimetrique (France)

ccarrizo@iram.fr

Highest mm-site in the world, high atmospheric transparency. Winter 2005/2006, summer 2006 eastern track extension completed.

6 antenna of 15m in diameter

Baselines extend up to 400 m

Soon they will extend up to 800 m

80 -115 GHz / 200 - 245 GHz

Resolution: 0.5 arcs @ 1.3mm

Sensitivity: 0.28 K in 1.6km/s @ 1.3mm

Envelopes with marginal or no deviation from sphericity in the AGB phase, in contrast to the PPN stage where envelopes show strong asymmetries (bipolar, multipolar). Some sources observed by PdBI are presented in this HR diagram; they represent about a 30 per cent of all the (published) PdB data in this range.

From a total of 35 PPNe emitting in CO:

17 already mapped by PdBI8 not observable by PdBI (low-dec)

4 no (or very weak) wings in the CO profiles

6 weak and/or low-quality CO spectra

About 40 AGB stars mapped by PdBI (Neri et al. 1998)

TT Cyg

Olofsson et al. (2000) A&A, 353, 383

SHELL 2

SHELL 1 35” = 7000 yrD = 510 pc

CLUMP

TT Cyg geometrically thin, no evidence for gas in and outside the shell, binary system, small clumps, one or two wind models, SHELL 2 has a different mass loss history (lower mass rate 1e-8 and mass), SHELL 1 (1000x larger rate). TT Cyg, U Cam and S Sct

have all detached shells detected in CO emission, though of different dynamical ages (10000 S Sct, 5000 U Cam).

PDBI 12CO(1-0)

TT Cyg

Olofsson et al. (2000) A&A, 353, 383

SHELL 2

SHELL 1 35” = 7000 yrD = 510 pc

CLUMP

TT Cyg. Models reproduce this copious episodic mass loss process, for stars with lower initial mass

PDBI 12CO(1-0)

Mi = 1.1 M0t = 800 yr

M = 0.008 M0

M [

M0/

yr]

TT Cyg

.

4 x

10-6

6 x

10-6

8 x

10-6

2 x

10-6

Schroder, Winters & Sedlmayr (1999), A&A 349, 898

IRC+10216

IRC+10216 arcs. Concentric arcs and rings give evidence for modulated mass loss, just detected in

the optical in other objects, but only in IRC10216 in a few molecular transitions; underlying mechanism

not yet understood

Mauron & Huggins (1999) A&A, 315, 284 Guélin et al. (2000) IAU Symp 197, 365

CFHT V-BAND PDBI CN(2-1)

DUST

15” = 400 yrD = 80 pc

M1-92

Bujarrabal et al. (1998) ApJ, 504, 915

M1-92. Molecular emission for the different velocity channels. Bipolar nebula. Lobes present empty holes inside, where a high-excitation region is detected in

the optical. A massive disk, contained in the equatorial plane, seems to be the undisrupted

remnant of the previous AGB envelope. Note the high-velocity molecular clumps that seem to escape

through the breakthrough seen in the optical

Bujarrabal et al. (1998) A&A, 331, 361

10000 AU = 4”

HST WFPC2 6300 A

BREAKTHROUGH

BREAKTHROUGH

PDBI 13CO(2-1)

M2-56. Tiny bipolar nebula in the optical (weaker emission is detected also farther). The molecular envelope is however not tiny, but extends up to 27 arcsec

M 2-56

HST image (Ha+continuum) by Trammell & Goodrich (1998) AAS 193, 1403

PdBI average map of the 12CO(2-1) emissionCastro-Carrizo et al. (2002) A&A 386, 633

M 2-56

Castro-Carrizo et al. (2002) A&A 386, 633

M2-56, maps and model. More in detail; CO shows also a bipolar nebula, in which probably part of the lobes have been

photo-dissociated.

12CO(2-1) 10

-10

0

20 10 0 -10East offset (arc.sec.)

North

off

set (a

rc.sec.)

-20

M 2-9

M2-9, CO vs. optical. Only a disk perpendicular to the bipolar optical nebula has been detected in CO; it

seems to be the remnant of the previous AGB envelope.

12CO(1-0)

Optical [NII] line emission (grey scale) by Balick et al. (1987) AJ 94, 671

12CO(1-0) emission (contours) at the systemic velocity, by Zweigle et al. (1997) A&A 324, 624

IRAS17436+5003, jets are still inside the previous AGB envelope. High sensitivity data. mm-

interferometry shows us what is happening inside the spherical envelopes that were created in the AGB phase, so the seed of the future nebular asymmetry

IRAS 17436+500312CO(2-1)

Alcolea et al. (2003) A&A in prep

CRL618, very fast jets still inside the previous AGB envelope. Clumpy structure in jets, double shell,

tentative minor jet2. PdB maps also of other molecules: hco+,hc3n,h41a,ch3cn. The radio

recombination line H41a coming from the inner 2arcsec region presents some bumps over its

gaussian profile; an example of other kind of data (different to molecular emission) that are obtained

by PdBI

JET2 ?

JET1

DOUBLE SHELL

Castro-Carrizo et al. (2003) in prep.

AFGL 618PDBI 12CO(2-1)

N

E

Neri et al. (2003) in prep. H41a

14.7 km/s

Frosty Leo. Present information: multiple-jet features in the optical, large amount of

gas accelerated in the post-AGB phase (CO)

Frosty Leo HST image at 0.6um

Sahai et al. (2000) A&A 360, L9 Main ejection +

multiple (apparently) minor jets

Multiple and complex substructures

Frosty Leo, CO maps show bipolar nebula. Its

symmetry axis seems to coincide with the (apparently) minor jet detected in the optical.

Frosty Leo

Castro-Carrizo et al. (2003), in prep.

12CO(2-1)

Frosty Leo, more in detail. The central velocity channels present a complex compact structure that

seems to be the result of several ejections; probably a first one, that shaped the optical nebula (about

3000 yr ago), and (at least) a second one that now we detect in CO (that probably took place about 1500 yr ago). Note that the central disk reaches

velocities as high as 30km/s; it is not therefore the undisrupted remnant of the previous AGB envelope

Frosty Leo12CO(2-1)

Castro-Carrizo et al. (2003), in prep.

Some conclusions, and a look at the future

To conclude …

Plateau de Bure is ready, with much better resolution and sensitivity!!

- to investigate the molecular distribution in envelopes with known concentric rings, in order to discriminate between chemical and dynamical models - to investigate the mass loss rate evolution, the clumpiness and the departures from spherical symmetry in AGB envelopes

mm interferometry unveils details in the innermost C.E.

More sensitivity and resolution is needed to improve and enlarge our sample of envelopes with rings/arcs in molecular tracers

High-sensitivity mm interferometry necessary to discriminate between physical models associated with the generation of winds and structures in C.E.

Plateau de Bure will be ready in future!! - to study polarization, so magnetic activity, in the innermost region- to observe molecular transitions at 2mm and 0.8mm (0.2”)

Others: Hyper-giants with massive molecular

envelopes, are they particular PPNe?

Hypergiants; the case of AFGL 2343 and IRC+10420

Castro-Carrizo et al. (2001) A&A 368, L34

Castro-Carrizo et al. in prep.

Particular PPNe ?

They present very massive spherical circumstellar envelopes

Thermal SiO emission coming from a detached shell !!

Special excitation conditions?, chemistry?, spherical shocks?

OH 231.8+4.2

Others: OH231.8 presented by J. Alcolea. Note also the PdB data obtained, for example, in CRL2688,

presented by P.Cox with multiple jet structure, and the first rotational disk detected in the Red Rectangle

by V.Bujarrabal et al.

Alcolea et al. (2001) A&A 373,932