scholarly journals Planetary nebulae: 20 years of Hubble inquiry

2011 ◽  
Vol 7 (S283) ◽  
pp. 53-58
Author(s):  
Bruce Balick
Keyword(s):  
Binary Stars ◽  
Hubble Space Telescope ◽  
Planetary Nebulae ◽  
Close Binary ◽  
Stellar Winds ◽  
Physical Processes ◽  
The Past ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Movie Camera

AbstractThe Hubble Space Telescope has served the critical roles of microscope and movie camera in the past 20 years of research on planetary nebulae (“PNe”). We have glimpsed the details of the evolving structures of neutral and ionized post-AGB objects, built ingenious heuristic models that mimic these structures, and constrained most of the relevant physical processes with careful observations and interpretation. We have searched for close physical binary stars with spatial resolution ~50 AU at 1 AU, located jets emerging from the nucleus at speeds up to 2000 km s−1 and matched newly discovered molecular and X-ray emission regions to physical substructures in order to better understand how stellar winds and ionizing radiation interact to form the lovely symmetries that are observed. Ultraviolet spectra of CNO in PNe help to uncover how stars process deep inside AGB stars with unstable nuclear burning zones. HST broadband imaging has been at the forefront of uncovering surprisingly complex wind morphologies produced at the tip of the AGB, and has led to an increasing realization of the potentially vital roles of close binary stars and emerging magnetic fields in shaping stellar winds.

42. Close Binary Stars (Etoiles Binaires Serrees)

1988 ◽  
Vol 20 (01) ◽  
pp. 569-594
Author(s):  
J. Smak ◽  
R.H. Koch ◽  
K.D. Abhyankar ◽  
J. Andersen ◽  
A.H. Batten ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Stellar Winds ◽  
Space Instruments ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Astronomy And Astrophysics

During the XlXth General Assembly of the IAU in Delhi the number of members of Cotrmission 42 increased to 260. This simply reflects the growing interest and importance of our field. Growing is not only the number of astronomers involved in research on CBS but also the number of papers resulting from that activity. As an example one can quote the numbers of papers listed during the last few years in Sections 117 (Close Binaries), 119 (Eelipsing Binaries), and 120 (Spectroscopic Binaries) of theAstronomy and Astrophysics Abstracts:705(1982), 775(1983), 836(1984), 1080(1985), and 911(1986); note that many additional references could be added to these numbers from other sections. Naturally, such numbers alone do not reflect the quality and even less so the position and significance of the CBS field. Here one could perhaps mention an impressive record of successful research proposals involving requests for the observing time on large, ground based telescopes and on space instruments. Indeed, in spite of a very strong competition from other fields, programs involving CBS are usually placed very high on the priority lists (cf. Sections 2D and 2E). Obviously, the close binary systems, their evolution, and the physical processes which occur in them (accretion, stellar winds, nuclear burning, etc) appear interesting and important not only to those who are involved in their studies but also to astronomers from other fields.

scholarly journals Planetary Nebulae Embryo after a Common Envelope Event

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 75 ◽  
Author(s):  
Natalia Ivanova ◽  
Jose Nandez
Keyword(s):  
Binary Stars ◽  
Planetary Nebulae ◽  
Close Binary ◽  
Common Envelope ◽  
Characteristic Speed ◽  
Close Binary Stars

In the centers of some planetary nebulae are found close binary stars. The formation of those planetary nebulae was likely through a common envelope event, which transformed an initially-wide progenitor binary into the currently observed close binary, while stripping the outer layers away. A common envelope event proceeds through several qualitatively different stages, each of which ejects matter at its own characteristic speed, and with a different degree of symmetry. Here, we present how typical post-common envelope ejecta looks kinematically a few years after the start of a common envelope event. We also show some asymmetric features we have detected in our simulations (jet-like structures, lobes, and hemispheres).

scholarly journals Lithium Depletion in Late-Type Stars Through Wind-Driven Mixing

1995 ◽  
Vol 10 ◽  
pp. 461-462 ◽  
Author(s):  
J.-P. Zahn
Keyword(s):  
Binary Stars ◽  
Causal Link ◽  
Close Binary ◽  
Late Type ◽  
Lithium Abundance ◽  
Convective Envelope ◽  
Halo Stars ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Lithium Depletion

A well established property of late-type stars is that their rotation rate and their lithium abundance both decline with age. We understand why such stars are spun down while losing so little mass (Schatzman 1962), but we are still working on a theory which would explain all aspects of the observed lithium depletion. Although most agree that some kind of mixing must occur below the convective envelope of late-type stars, which transports 7Li to the depth where it is destroyed through nuclear burning, the physical process which is responsible for this transport is still in debate. However the most recent observations of the lithium abundance in close binary stars clearly show that there is a causal link between the destruction of lithium and the loss of angular momentum: consistently, tidally-locked binaries tend to display more lithium than single stars of the same effective temperature, as observed in the Hyades (Soderblom et al. 1990, Thorburn et al. 1993) and among old disk stars and halo stars (Spite et al. 1994).

scholarly journals Close Binary Stars in Planetary Nebulae through Gaia EDR3

2021 ◽  
Vol 7 (1) ◽  
pp. 40
Author(s):  
Iker González-Santamaría ◽  
Minia Manteiga ◽  
Carlos Dafonte
Keyword(s):  
Big Data ◽  
Binary Stars ◽  
Binary Systems ◽  
Planetary Nebulae ◽  
Statistical Test ◽  
Close Binary ◽  
Close Binary Systems ◽  
Close Binary Stars ◽  
Stellar Envelopes ◽  
Central Stars

The aim of this work is to search for evidence of close binary stars associated with planetary nebulae (ionized stellar envelopes in expansion) by mining the astronomical archive of Gaia EDR3. For this task, using big data techniques, we selected a sample of central stars of planetary nebulae from almost 2000 million sources in an EDR3 database. Then, we analysed some of their parameters, which could provide clues about the presence of close binary systems, and we ran a statistical test to verify the results. Using this method, we concluded that red stars tend to show more affinity with close binarity than blue ones.

scholarly journals Surveying Planetary Nebulae Central Stars for Close Binaries: Constraining Evolution of Central Stars Based on Binary Parameters

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 85 ◽  
Author(s):  
Todd Hillwig
Keyword(s):  
Binary Stars ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Close Binary ◽  
Close Binaries ◽  
Common Envelope ◽  
Close Binary Stars ◽  
Red Giant ◽  
The Relationship ◽  
Central Stars

The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary nebula formation. Herein I review some of the recent results and conclusions specifically relating close binary central stars to nebular shaping, common envelope evolution off the red giant branch, and the total binary fraction and double degenerate fraction of central stars. Finally, I use parameters of known binary central stars to explore the relationship between the proto-planetary nebula and planetary nebula stages, demonstrating that the known proto-planetary nebulae are not the precursors of planetary nebulae with close binary central stars.

scholarly journals 42. Close Binary Stars

1985 ◽  
Vol 19 (1) ◽  
pp. 584-606
Author(s):  
A. H. Batten ◽  
J. Smak ◽  
K. D. Abhyankar ◽  
J. Andersen ◽  
A. M. Cherepashchuk ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Close Binary ◽  
The Past ◽  
Close Binary Systems ◽  
Rate Of Growth ◽  
Natural Development ◽  
Close Binary Stars ◽  
The Subject ◽  
High Level

Research on close binary systems has continued at a high level during the past triennium, although the rate of growth is noticeably slower – probably reflecting the cutbacks in funds to which many of us are subject. There have also been changes of emphasis within the field, which are commented on in the pages that follow. These reflect both changing opportunities for observation and the natural development of the subject. In many areas, the time is ripe for a more critical look at ideas that previously seemed adequate.

scholarly journals Physical Processes in Nebular Shells and the Interpretation of Nebular Spectra

1983 ◽  
Vol 103 ◽  
pp. 219-227
Author(s):  
J. Patrick Harrington
Keyword(s):  
Charge Transfer ◽  
Simple Model ◽  
Stellar Wind ◽  
High Velocity ◽  
Planetary Nebulae ◽  
Geometrical Parameters ◽  
Stellar Winds ◽  
Physical Processes ◽  
Rapid Cooling ◽  
Particle Distributions

Computed models are now recognized as useful tools for interpretation of the spectra of planetary nebulae. However, even the most detailed models need geometrical parameters such as filling factors which are poorly determined by observations. Some effects may be seen more clearly by modeling the stratification than by just using total fluxes. A simple model for NGC 6720 is presented which reproduces the behavior of (Ne III) λ3869 observed by Hawley and Miller (1977), clearly showing the effects of charge transfer. The behavior of C II λ4267 remains puzzling. Finally, we comment on the interaction of high velocity stellar winds with nebular shells. Non-equilibrium particle distributions at the contact between the shocked stellar wind and the nebula may result in the rapid cooling of the shocked gas.

Radial Velocity Studies of Close Binary Stars. II.

1999 ◽  
Vol 118 (5) ◽  
pp. 2451-2459 ◽  
Author(s):  
Slavek M. Rucinski ◽  
Wenxian Lu
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Close Binary ◽  
Close Binary Stars
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