Accretion Disks in Pre-Planetary Nebulae

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

40

Accretion, Accretion Disks, Ism: Jets And Outflows, Ism: Planetary Nebulae: General, Stars: Agb And Post-Agb

Scientific paper

A number of planetary nebulae (PNs) exhibit collimated, high-velocity outflows or jets. These hydrodynamical structures cannot be easily accommodated within the classical models of the evolution of post-asymptotic giant branch stars, and understanding them has become a topical problem in PN research. One way to explain the existence of jets in PNs has been to invoke the presence of accretion disks, which would presumably set the conditions for the collimation and driving of the outflows. This work investigates in detail the type of binary systems that are likely to lead to Roche-lobe overflow (RLOF) and the formation of accretion disks as a consequence of common-envelope evolution, and explores the expected basic physical structure of such disks. The results of the analysis show substantial restrictions on the composition of binary systems that can form a disk upon accretion onto the primary. Typically, it is found that for a primary asymptotic giant branch (AGB) core of 0.6 M_solar and envelope mass of 2-3 M_solar, secondaries with M_2>~0.08 M_solar and initial separation a_i>~200 R_solar will not lead to RLOF. For systems that do lead to RLOF, this is achieved at orbital separations <2 R_solar. We also find that dynamically stable mass transfer from secondaries with M_2>~0.08 M_solar does not lead to disk formation, since the circularization radius lies below the surface of the AGB core. Only lower mass companions, after a dynamically unstable mass transfer process, may lead to disk formation. Under reasonable simplifying assumptions, we estimate the resulting accretion disk properties and evolution and discuss their potential role in driving collimated outflows.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Accretion Disks in Pre-Planetary Nebulae does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Accretion Disks in Pre-Planetary Nebulae, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Accretion Disks in Pre-Planetary Nebulae will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1084008

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.