Departures from Axisymmetry in PNe and SN1987A

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Departures from Axisymmetry in PNe and SN1987A

• M. Bobrowsky

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• Axisymmetry is well known. (It forms in the
  last part of the superwind phase -- e.g., see
  poster by Speck Dijkstra)
• Classifications and correlations done by
• Balick 1987, 2007 (APN4)
• Corradi Schwarz 1995
• Manchado et al. 1996, 2000
• Sahai et al. 2007
• Schwarz, Corradi, Stanghellini 1992
• Shaw et al. 2001
• Stanghellini et al. 1999, 2000, 2002

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• Classification of deviations from axisymmetry
• Soker Hadar (2002) considered several types of
  departure from axisymmetry
• Limited mainly to departures in the equatorial
  plane

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• Cause of departure external or internal
• External (e.g., interaction with the ISM)
• Observations Jacoby 1981 Tweedy Kwitter
  1994, 1996 Xilouris et al. 1996 Kerber et al.
  2000, 2001 Muthu, Anandarao Pottasch 2000,
  Rauch et al. 2000 Martin, Xilouris Soker 2002
• Theory Borkowski, Sarazin, Soker 1990 Soker,
  Borkowski, Sarazin 1991 Villaver, Manchado,
  Garcia-Segura 2000Villaver, Garcia-Segura,
  Manchado 2003 Villaver, Garcia-Segura,
  Manchado 2003 Dgani Soker 1998 see Dgani 2000
  for a review

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• Internal Departure (e.g., binary companion)
• Observations
• Soker, Rappaport, Harpaz 1998 Soker 1994, 1999
• Theory
• Sahai 2000 Miranda et al. 2001 Miranda,
  Guerrero, Torrelles 2001

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• About 50 of all PNe in Soker and Hadars sample
  have large-scale departure (compared to a 25-30
  incidence of binaries).
• In the present work, 58 were found to have a
  departure from axisymmetry.

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Questions to Answer

• What can we learn from the departures from
  axisymmetry?
• Can departures be generalized to other objects?

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Types of Departure
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Types of Departure

• Displacement of the Central Star

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IC 418
(Also see poster by Morisset Georgiev)
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MyCn 18
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MyCn 18
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Hen 3-1357 (The Stingray Nebula)
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Central Star Displacement in the Stingray Nebula

• ?R/R 10
• Assume age 104 yr, mass of companion 1 Msun,
  and mass of central star 1 Msun before losing
  mass.
• --gt orbital period 7.3 ? 104 yr
• Distance of central star from CM of system 1100
  AU
• Orbital velocity 0.5 km s-1
• --gt During nebular formation, star moved 1/8 of a
  circle in its orbit -- approximately 45.

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SN 1987A
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Types of Departure

• Displacement of the central star

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Types of Departure

• Displacement of the central star
• Unequal size and shape of two sides

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IRAS 16268-4556 Hen 2-166
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IRAS 201192924 Hen 2-459
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Types of Departure

• Displacement of the central star
• Unequal size and shape of two sides

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Types of Departure

• Displacement of the central star
• Unequal size and shape of two sides
• Bent planetary nebulae

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IRAS 16409-1851 Hen 2-180
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IRAS 16409-1851 Hen 2-180
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NGC 6886
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Types of Departure

• Displacement of the central star
• Unequal size and shape of two sides
• Bent planetary nebulae

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Types of Departure

• Displacement of the central star
• Unequal size and shape of two sides
• Bent planetary nebulae
• Different lobe structures

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IRAS 212825050 J900
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PK 130-111
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Why different structures?

• Instabilities in outer lobes when a fast wind
  interacts with jets? (See poster by Akashi,
  Soker, Blondin.)
• Fragmentation of explosively launched clumps?
  (See poster by Dennis, Cunningham, Frank, Balick,
  Mitran.)
• Other possibilities?

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Podsiadlowski Cumming 1994
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SN 1987A Model
Morris Podsiadlowski 2007, Science, 315,
1103 Podsiadlowski 2007, APN4
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How to explain the additional 2 km sec-1
velocity?

• Possibilities include
• a non-radial pulsational mode excited during the
  early spiral-in phase
• orbital motion caused by a more distant low-mass
  third star in the system

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Conclusions

• Departures from axisymmetry are significant and
  measurable.
• Orbital motion can give expelled mass additional
  velocity in the direction of orbital motion.
• Prospects for the Future Generalize to other
  types of objects? Possibly, but use caution!