Physical conditions of the shocked regions in collimated outflows of planetary nebulae
Download
1 / 20

Physical conditions of the shocked regions in collimated outflows of planetary nebulae - PowerPoint PPT Presentation


  • 99 Views
  • Uploaded on

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.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Physical conditions of the shocked regions in collimated outflows of planetary nebulae' - jabir


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
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 outflows of planetary nebulae

  • 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 outflows of planetary nebulae

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.


  • Kinematics outflows of planetary nebulae

    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).


  • FLIERs outflows of planetary nebulae (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


Studies of the Physical Conditions of shock-excited features outflows of planetary nebulae.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’ outflows of planetary nebulae

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

Guerrero et al. (in preparation)


K 4-47 outflows of planetary nebulae

Figure from Gonçalves et al. (2004)

M 2-48

Figure from Vázquez et al. (2000)

Figure from Gonçalves et al. (2004)


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.


NGC 7009 denser than the nebular gas (10

NGC 6543

IC 4634


Δ denser than the nebular gas (10M1-92, 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)


Δ denser than the nebular gas (10 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 denser than the nebular gas (10(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.


  • Parameters denser than the nebular gas (10

  • 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 denser than the nebular gas (10

M1

M3

M2

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


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

M2


M1 integration time of 200 years.

M2

M3


Diagnostic diagrams
Diagnostic diagrams integration time of 200 years.

● ○ Numerical simulations


Conclusions
CONCLUSIONS integration time of 200 years.

  • 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.


ad