scholarly journals Binary Central Stars of Planetary Nebulae

Galaxies ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 28 ◽  
Author(s):  
David Jones
Keyword(s):  
Planetary Nebulae ◽  
Current Understanding ◽  
Intermediate Mass ◽  
Single Star ◽  
Intermediate Mass Stars ◽  
Binary Evolution ◽  
Central Stars

It is now clear that a vast majority of intermediate-mass stars have stellar and/or sub-stellar companions, therefore it is no longer appropriate to consider planetary nebulae as a single-star phenomenon, although some single, isolated stars may well lead to planetary nebulae. As such, while understanding binary evolution is critical for furthering our knowledge of planetary nebulae, the converse is also true: planetary nebulae can be valuable tools with which to probe binary evolution. In this brief review, I attempt to summarise some of our current understanding with regards to the role of binarity in the formation of planetary nebulae, and the areas in which continued study of planetary nebulae may have wider ramifications for our grasp on the fundaments of binary evolution.

scholarly journals New models for the evolution of central stars of planetary nebulae: Faster and Brighter

2016 ◽  
Vol 12 (S323) ◽  
pp. 179-183
Author(s):  
Marcelo M. Miller Bertolami
Keyword(s):  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Intermediate Mass ◽  
Short Article ◽  
Intermediate Mass Stars ◽  
New Models ◽  
Central Stars

AbstractThe post-asymptotic giant branch (AGB) phase is arguably one of the least understood phases of the evolution of low- and intermediate- mass stars. The recent post-AGB evolutionary sequences computed by Miller Bertolami (2016) are at least three to ten times faster than those previously published by Vassiliadis & Wood (1994) and Blöcker (1995) which have been used in a large number of studies. This is true for the whole mass and metallicity range. The new models are also ~0.1–0.3 dex brighter than the previous models with similar remnant masses. In this short article we comment on the main reasons behind these differences, and discuss possible implications for other studies of post-AGB stars or planetary nebulae.

S-process Elements in Binary Central Stars of Planetary Nebulae

2018 ◽  
Vol 14 (S343) ◽  
pp. 452-453
Author(s):  
Lisa Löbling ◽  
Henri Boffin
Keyword(s):  
Neutron Capture ◽  
Planetary Nebulae ◽  
Slow Neutron ◽  
Asymptotic Giant Branch ◽  
Intermediate Mass ◽  
Element Abundances ◽  
Evolved Stars ◽  
Intermediate Mass Stars ◽  
Process Elements ◽  
Central Stars

AbstractLow- and intermediate-mass stars experience a phase of carbon enrichment and slow neutron-capture nucleosynthesis (s-process) on the asymptotic giant branch. An interesting element is the radioactive technetium, whose presence is a clear indication that nucleosynthesis happened recently. Analysing the element abundances not only in the hot evolved stars at the center of planetary nebulae helps to derive constraints for the evolution of these stars. Doing so also in their companions if they are in a binary, provides information on the mass-transfer history.

scholarly journals Planetary nebulae seen with TESS: Discovery of new binary central star candidates from Cycle 1

2020 ◽  
Vol 635 ◽  
pp. A128 ◽  
Author(s):  
A. Aller ◽  
J. Lillo-Box ◽  
D. Jones ◽  
L. F. Miranda ◽  
S. Barceló Forteza
Keyword(s):  
Main Sequence ◽  
Planetary Nebulae ◽  
Central Star ◽  
Statistical Validation ◽  
Low Mass ◽  
The Common ◽  
Binary Evolution ◽  
The Individual ◽  
Central Stars

Context. It has become clear in recent years that binarity plays a crucial role in many aspects of planetary nebulae (PNe), particularly with regard to the striking morphologies they exhibit. To date, there are nearly 60 known binary central stars of PNe (bCSPNe). However, both theory and observation indicate that this figure represents only the tip of the iceberg, with the Galactic PN population hosting orders of magnitude more stars. Aims. We are involved in a search for new bCSPNe with the aim of enhancing the statistical validation of the key role of binarity in the formation and shaping of PNe. New discoveries of bCSPNe and their characterization carry important implications not only for understanding PN evolution, but also for studying binary evolution and the common-envelope phase, which is still poorly understood. Methods. We used data from the TESS satellite to search for variability in the eight CSPNe that belong to the two-minute cadence of preselected targets in Cycle 1, with their available pipeline-extracted light curves. We identified strong periodicities and analysed them in the context of the binary scenario. Results. All the CSPNe but one (Abell 15) show clear signs of periodic variability in TESS. The cause of this variability can be attributed to different effects, some of them requiring the presence of a companion star. We find simple sinusoidal modulations in several of the systems, compatible with irradiation effects. In addition, two of the central stars (PG 1034+001 and NGC 5189) also show photometric variations due to ellipsoidal variations and other signs of variability that are probably caused by star spots or relativistic Doppler-beaming. The case of the well-studied Helix Nebula is of particular interest; here we constructed a series of binary models to explain the modulations we see in the light curve. We find that the variability constrains the possible companion to be very low-mass main-sequence star or sub-stellar object. We also identify, in substantial detail, the individual pulsation frequencies of NGC 246.

scholarly journals Imaging the elusive H-poor gas in planetary nebulae with large abundance discrepancy factors

2016 ◽  
Vol 12 (S323) ◽  
pp. 65-69 ◽  
Author(s):  
Jorge García-Rojas ◽  
Romano L. M. Corradi ◽  
Henri M. J. Boffin ◽  
Hektor Monteiro ◽  
David Jones ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Tunable Filter ◽  
Close Binary ◽  
Chemical Abundances ◽  
Dual Nature ◽  
Gas Phases ◽  
Binary Evolution ◽  
The Universe ◽  
Central Stars

AbstractThe discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O ii ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O ii ORL emission is more centrally concentrated than that of [Oiii] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.

scholarly journals Near–Infrared Imaging of Proto-Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 340-340 ◽  
Author(s):  
R.E.S. Clegg ◽  
N. A. Walton ◽  
M.J. Barlow
Keyword(s):  
Molecular Hydrogen ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Planetary Nebulae ◽  
Agb Stars ◽  
Intermediate Mass ◽  
Preliminary Results ◽  
Near Ir ◽  
Intermediate Mass Stars ◽  
Hydrogen Lines

It is not really known how low and intermediate mass stars eject mass to form PNs. We present preliminary results from a programme of near–IR imaging, in which we study a sequence of objects, from extreme AGB stars through proto–planetaries to young, compact PNs. We aim to study the sequence of morphologies, to see where the onset of bipolar shaping occurs, and to use the IR molecular hydrogen lines to map neutral regions around ionized nebulae.

scholarly journals The Role of Binarity in Wolf-Rayet Central Stars of Planetary Nebulae

2015 ◽  
Vol 71-72 ◽  
pp. 117-120 ◽  
Author(s):  
B. Miszalski ◽  
R. Manick ◽  
V. McBride
Keyword(s):  
Planetary Nebulae ◽  
Central Stars

scholarly journals Red Giants as Precursors of Planetary Nebulae

1983 ◽  
Vol 103 ◽  
pp. 267-280 ◽  
Author(s):  
Alvio Renzini
Keyword(s):  
Binary Stars ◽  
Planetary Nebulae ◽  
Mass Range ◽  
Dust Formation ◽  
Red Giants ◽  
Circumstellar Envelopes ◽  
Physical Processes ◽  
Intermediate Mass ◽  
Intermediate Mass Stars ◽  
Thermal Pulses

Several physical processes taking place during the red (super)giant phase of intermediate-mass stars have direct observational consequences for the subsequent nebular stage. These processes include: the regular wind and the envelope ejection, the thermal pulses during the AGB phase, the dredge-up processes, and the dust formation in expanding circumstellar envelopes. In this paper it is briefly discussed how such processes affect the mass range of PN nuclei and their evolution, and the PN lifetime, composition and dust content. The last section is devoted to a cursory discussion of PNe which can be generated by binary stars.

scholarly journals AGBs, Post-AGBs and the Shaping of Planetary Nebulae

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 99 ◽  
Author(s):  
Eric Lagadec
Keyword(s):  
Angular Resolution ◽  
Hubble Space Telescope ◽  
Planetary Nebulae ◽  
High Angular Resolution ◽  
Agb Stars ◽  
Intermediate Mass ◽  
Intermediate Mass Stars ◽  
Shaping Process ◽  
Huge Variety ◽  
Isotropic Radiation

During the last decades, observations, mostly with the Hubble Space Telescope, have revealed that round Planetary Nebulae were the exception rather than rule. A huge variety of features are observed, such as jets, discs, tori, showing that the ejection of material is not due to isotropic radiation pressure on a spherical shell and that more physics is involved. This shaping process certainly occur early in the evolution of these low and intermediate mass stars and must leave imprints in the evolutionary stages prior the PN phase. Thanks to news instruments on the most advanced telescopes (e.g., the VLTI, SPHERE/VLT and ALMA), high angular resolution observations are revolutionising our view of the ejection of gas and dust during the AGB and post-AGB phases. In this review I will present the newest results concerning the mass loss from AGB stars, post-AGB stars and related objects.

scholarly journals Role of nuclear reactions on stellar evolution of intermediate-mass stars

2018 ◽  
Vol 940 ◽  
pp. 012050
Author(s):  
H Möller ◽  
S Jones ◽  
T Fischer ◽  
G Martínez-Pinedo
Keyword(s):  
Stellar Evolution ◽  
Nuclear Reactions ◽  
Intermediate Mass ◽  
Intermediate Mass Stars

scholarly journals The role of heat conduction to the formation of [WC]-type planetary nebulae

2011 ◽  
Vol 7 (S283) ◽  
pp. 494-495
Author(s):  
Christer Sandin ◽  
Matthias Steffen ◽  
Ralf Jacob ◽  
Detlef Schönberner ◽  
Ute Rühling ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Chemical Composition ◽  
Physical Properties ◽  
Planetary Nebulae ◽  
Time Dependent ◽  
Diffuse Emission ◽  
Hydrodynamic Models ◽  
X Ray ◽  
Central Stars

AbstractX-ray observations of young Planetary Nebulæ (PNe) have revealed diffuse emission in extended regions around both H-rich and H-deficient central stars. In order to also reproduce physical properties of H-deficient objects, we have, at first, extended our time-dependent radiation-hydrodynamic models with heat conduction for such conditions. Here we present some of the important physical concepts, which determine how and when a hot wind-blown bubble forms. In this study we have had to consider the, largely unknown, evolution of the CSPN, the slow (AGB) wind, the fast hot-CSPN wind, and the chemical composition. The main conclusion of our work is that heat conduction is needed to explain X-ray properties of wind-blown bubbles also in H-deficient objects.

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