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STUDYING THE FAST WIND IN PPNs VIA H 2 Bruce J. Hrivnak (Valparaiso University, USA)

STUDYING THE FAST WIND IN PPNs VIA H 2 Bruce J. Hrivnak (Valparaiso University, USA). Doug Kelly, Kate Su (U. Arizona) Sun Kwok (U. Calgary) Ken Hinkle (NOAO) Raghavendra Sahai (JPL). Why? Surveys to identify H 2 in PPNs --> correlations? --> mechanisms?

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STUDYING THE FAST WIND IN PPNs VIA H 2 Bruce J. Hrivnak (Valparaiso University, USA)

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  1. STUDYING THE FAST WIND IN PPNs VIA H2 • Bruce J. Hrivnak (Valparaiso University, USA) Doug Kelly, Kate Su (U. Arizona) Sun Kwok (U. Calgary) Ken Hinkle (NOAO) Raghavendra Sahai (JPL) • Why? • Surveys to identify H2 in PPNs • --> correlations? • --> mechanisms? • Spatial imaging of H2 • --> location of the emission? • Model of Evolution • Kinematics Egg Nebula (Sahai et al. 1998) H2(red), 1.6 mm(green), 0.6mm(blue) APN3: (Mt. Rainier 2003-07)

  2. INTRODUCTION: Why study H2 in PPNs? Shaping of PNs: Substantial shaping occurs early in the PPN phase (or even at the end of the AGB phase). Factors to investigate: - variation of density with latitude in CSE – circumstellar disks - variation of mass loss with latitude - initiation of fast wind, which shapes the density variation • How to investigate the initiation of the fast wind? • - extended wings in CO millimeter-line observations (+/- 100 km/s) • - extended wings in Ha emission • - H2 emission • H2 signature of fast wind: • - collisional excitation - shocks at interaction with AGB remnant • - location at the ends of lobes, away from star • - kinematics of H2emission

  3. SURVEYS TO IDENTIFY H2 IN PPNs: Kelly & Hrivnak (in prep): (+ other studies, discuss shortly) Steward Obs. 2.3-m telescope with FSpec, R~2600 2.10 - 2.35 mm {1-0 S(1), 1-0 S(0), 2-1 S(1), 2-1 S(2), 3-2 S(3)} Detected H2 in 15/50 sources (12 new detections) (1) F-G stars: 7/30 5 are bipolar (with optically-thick regions) (2) B star: 7/8 (+ 1 very young PN) 1-0 S(1) 1-0 S(0) 2-1 S(1)

  4. B PN F B B1 B G2 B B G HII

  5. SURVEYS: Correlations with properties +Garcia-Hernandez et al. 2002 (SH); Weintraub et al. 1998; AFGL 618, 2688 (+10/30 sources) 0/7 7/36 1/6 13/15 Kelly & Hrivnak (15/50 sources, NH) Spectral Type: - M: 0/3 - F-G: 6/30 - A: 0/5 - B: 7/8 Morphology: - F-G: bipolar (optically-thick) 4/4 bipolar (optically-thin) 0/3 unknown: 2/2 non-bipolar* 0/21 - B: bipolar 0/0 non-bipolar 7/8 5/5 0/4 2/2 0/25 2/2 11/13 Galactic Latitudes: - F-G: with H2 3.6 (±1.2, n=5) - F-G: without H2 8.2 (±1.5, 24) - B: with H2 8.1 (±2.4, 7) 3.6 (±1.0, 7) 8 (±1, 29) 7.0 (±1.4, 13) * Detection limit compromised by contrast effect in non-bipolars with bright stellar continuum. Note: Garcia-Hernandez et al. found similar results for spectral type correlation.

  6. SURVEYS TO IDENTIFY H2 IN PPNs: • Excitation Mechanism? • Ratio H2 1-0 S(1)/2-1 S(1) • > 10  collisional ex. IRAS 17150-3224 (G2) • 1.3-2.0  radiative ex. IRAS 20462+3416 (B1) • v > 2  radiative all the B stars + results of morphological correlations Results for PPNs with H2: F-G stars: primarily collisional, associated with bipolar shape B stars: primarily radiative, apparently not assoc. with bipolar shape Most are some mixture of collisional and radiative Van de Steene & van Hoof (2003) - Careful study of IRAS 16594-4656 including additional H2 lines; indicates mainly collisional excitation and they also discusses types of shocks.

  7. SPATIAL IMAGING OF PPNs: Egg Nebula (Sahai et al. 1998) – F5 (collisional) Location of H2 Rob 22 (A) (rad +?) Hen 3-401 (B) (collisional) Sahai et al. 1999, APNII Conf.

  8. SPATIAL IMAGING OF PPNs: IRAS 17150-3224 - G2 (collisional) H2 H2(red), I(green), V(blue) V Location of H2: primarily at ends of lobes - clumps, faint loop (skirt) around equator.

  9. IRAS 17441-2411 1” V H2 J (1.2 mm) V H (1.6 mm) H2 1”

  10. IRAS 16594-4656 2” H2 J V IRAS 18379-1707 H2 H (1.6 mm) 1”

  11. MODEL OF EVOLUTION: B* bipolar H2 in lobes col + rad G* bipolar H2 in lobes collisional PN bipolar H2 in disk collisional higher-M progenitor B* non-bipolar H2 near star radiative G* elliptical no H2 PN non-bipolar no H2 lower-M progenitor Similar scenario by Garcia-Hernandez et al. (2002)

  12. KINEMATICS: AFGL 2688, 618 – Kastner et al. (2001) – high resolution Phoenix observations

  13. KINEMATICS: AFGL 2688, 618 – Kastner et al. (2001) • deceleration of outflow along the bipolar axis in Egg Nebula, AFGL 618.

  14. KINEMATICS: Work in Progress IRAS 17150-3224 Phoenix on 4-m KPNO (G2) | slit along major axis  (continuum-subtracted) Lobes: DV = 40 km/s Center: split into blue and red, width = 10 km/s (see Kelly poster for more details)

  15. KINEMATICS: Work in Progress Phoenix on 8-m Gemini-S Rob 22 (SpT=A) slit along major axis • IRAS 19306+1407 (B) • med-res spectrum indicates both • collisional and radiative excitation. • high-res spectrum (right) shows • (a) knot from center, blue-shifted, • width = 10 km/s • (b) extended region, width = 60 km/s (continuum-subtracted)

  16. H2 IN PPNs: SUMMARY • H2 is common in bipolar F-G PPNs with optically-thick torus • - shock excited • - occurs in lobes, near ends • - not seen in non-bipolar F-G PPNs •  fast wind beginning in SpT=G, but not earlier • (2) H2 is universal(?) in B PPNs, irrespective of morphology • - mostly radiatively excited •  phase that all PPNs go through prior to photo-dissociation • of H2 and photo-ionization of nebula (PN) • (3) High-resolution spectra now becoming available to study the • kinematics in detail. • - spatial-kinematic studies

  17. Equatorial Structures APNIII - 2003

  18. Shaping: due to fast outflow – can we see the initiation of it? Evidence for a fast outflow seen in extended wings of submm CO lines in a few PPNs: Egg Nebula, AFGL 618, IRAS 19500-1709 Can also look for interaction between fast outflow and AGB remnant. 1-0 S(1) 1-0 S(0) 2-1 S(1) Shocked H2 - Egg Nebula: H2 seen at ends of lobes and ends of obscuring region - IRAS 17150-3224 (below): seen at ends of lobes (HST-NICMOS) High H2 1-0 S(1)/2-1 S(1) ratio indicates collisional excitation

  19. IRAS 18379-1707

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