Physical conditions of the shocked regions in collimated outflows of planetary nebulae
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Physical conditions of the shocked regions in collimated outflows of planetary nebulae. Angels Riera (UPC). OUTLINE. Identification: morphology and kinematics. Physical conditions in shocked regions of PNe: NGC 6543, NGC 7009, IC 4634.

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Physical conditions of the shocked regions in collimated outflows of planetary nebulae

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Physical conditions of the shocked regions in collimated outflows of planetary nebulae

Physical conditions of the shocked regions in collimated outflows of planetary nebulae

Angels Riera (UPC)


Outline

OUTLINE

  • Identification: morphology and kinematics.

  • Physical conditions in shocked regions of PNe:

    NGC 6543, NGC 7009, IC 4634.

  • Irradiated shocks: observational properties and numerical simulations.


Identification

IDENTIFICATION

Small-scale structures which differ from their surroundings in emission line spectra (low-excitation spectra) and velocities.

  • Morphology

    Pair or string of knots, jet-like structures which appear in opposite symmetrical pairs, or point-symmetrical features.


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

  • Kinematics

    The first high-velocity collimated outflow in a PN was found by Gieseking, Becker & Solf (1985) in NGC 2392, Vexp = 200 km s-1

    Jets and “ansae”:

    NGC 6543 (Miranda & Solf 1992): Vexp = 130 (250) km s-1

    Hubble 4 (López, Steffen & Meaburn 1997): Vexp= 200 km s-1

    MyCn 18 (O’Connor et al. 2000): V in excess of 500 km s-1

    NGC 7009 (Fernández, Monteiro & Schwarz 2004) : proper motion measurements Vexp = 115 km s-1

    Reviews: López (2000, 2002), Gonçalves (2004), Corradi (2006).


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

  • FLIERs (Fast Low Ionization Emission Region)

    Balick et al. (1987, 1993, 1994)

    Morphology of jets or knots (axial symmetry).

    Sizes = few x 1016 cm. Doppler shifts ± 25 – 50 km s-1.

  • BRETs (Bipolar, Rotating, Episodic jeT) (López et al. 1993)

    Point-symmetric pair or string of knots.

  • LIS (Low Ionization Structures) (Corradi et al. 1996, Gonçalves et al. 2001).

    Sub-class of jet-like structures (moderate to high expansion velocities).

    associated with collimated outflows


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

Studies of the Physical Conditions of shock-excited features.Balick et al. (1993, 1994), Hajian et al. (1997), Balick et al. (1998),Gonçalves et al. (2003), Perinotto et al. (2004).

NGC 6543

Credit: NASA, ESA,HEIC, and the Hubble Heritage Team (STScI/AURA).

  • Spectral properties: high low ionization lines ([O I], [N II], [S II], [O II]).

  • Kinematics: Doppler shifts ± 25 to 50 km s-1

  • Ionization stratification: decreasing gradient of ionization with distance from the star (HST + WFPC2).

  • Moderate temperatures and densities.

Figure fromBalick et al. (1998)


Ic 4634 bow shaped structures a a b b

IC 4634: Bow-shaped structures A,A’, B, B’

Hα, [N II] and [O III] composite pictures of A, A’.

Guerrero et al. (in preparation)


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

K 4-47

Figure from Gonçalves et al. (2004)

M 2-48

Figure from Vázquez et al. (2000)

Figure from Gonçalves et al. (2004)


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

STIS data of NGC 7662 (Perinotto et al. 2004): FLIERs are denser than the nebular gas (104 cm-3); Te [N II] from 9800 to 12000 k.


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

NGC 7009

NGC 6543

IC 4634


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

ΔM1-92, M2-56, OH238.1+4.2 Trammell. Dinerstein & Goodrich (1993), Sánchez Contreras et al. (2000)

□ Hen 3-1475 (STIS + HST, ground spectroscopy)

Riera et al. (1995, 2003)

* CRL 618 (STIS + HST) (Riera et al. In prep.)

□BS M 2-48, K 4-47(ground-spect.) López-Martín et al. (2002),

Gonçalves et al. (2004).

▲ Δ NGC 7009 (ground-spect.) Balick et al. (1994), Gonçalves et al. (2003).

■ □ IC 4634 (ground-spect.) Guerrero et al. (in prep.)

● ○NGC 6543 (ground-spect.) Balick et al. (1994)


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

Δ M1-92, M2-56, OH238.1+4.2

□ Hen 3-1475

* CRL 618

□BS M 2-48, K 4-47

▲ ΔNGC 7009(WFPC2)

(reduced images provided by B. Balick). Balick et al. (1998)

■ □ IC 4634(WFPC2)

Guerrero et al. (in prep.)

● ○ NGC 6543 (WFPC2)

(reduced images provided by B. Balick; Balick 2004).

Lame, Harrington &

Borkowski (1997)


Irradiated shocks numerical simulations raga riera mellema in prep

Irradiated shocks: numerical simulations (Raga, Riera & Mellema in prep.)

  • Description

  • 2D, axisymmetric simulations of a high velocity bullet that moves away from the central star through the photoionized, nebular gas.

    We include the radiation field from the central star that penetrates the recombination region behind the leading bow-shock in the direction from the post-shock to the pre-shock region.

  • Gasdynamic code (described in Mellema et al. (1997)) using a 3-level binary adaptative grid, that includes radiative, dielectronic and charge exchange recombinations, collisional ionization and photoionization for several species.


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

  • Parameters

  • Clump: n = 103 cm-3 , T = 104 K, r = 1016 cm. V = 100 km s-1 .

    Fully (singly) ionized (i.e. H+/H = 1, He+/He = 1).

  • Ambient gas: n = 102 cm-3 , T = 104 K. Fully (singly) ionized.

  • Chemical abundances: mean PN abundances (Kingsburgh & Barlow 1994)

  • Stellar parameters: T* (BB) = 50000 K, L* = 5000 LΘ


Results

Results

M1

M3

M2

Density (cm-3) (top panels) and neutral fraction of H (bottom panels) at different integration times.


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

Fraction of different ions of O for model M2 for an integration time of 200 years.

M2


Physical conditions of the shocked regions in collimated outflows of planetary nebulae

M1

M2

M3


Diagnostic diagrams

Diagnostic diagrams

● ○ Numerical simulations


Conclusions

CONCLUSIONS

  • High spatial spectroscopy of shocked regions in PNe is needed: are FLIERs denser than the surrounding nebular gas?.

  • Numerical simulations of “irradiated shocks” reproduce some of the properties observed in shock-excited regions in PNe, as the decreasing gradient of ionization with distance to the star.

    We have to explore with larger values of the stellar temperature or/and the velocity of the clump.


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