scholarly journals Binary Stars and Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 505-522 ◽  
Author(s):  
Icko Iben ◽  
Alexander V. Tutukov
Keyword(s):  
Neutron Star ◽  
Binary Star ◽  
Planetary Nebulae ◽  
Roche Lobe ◽  
Asymptotic Giant Branch ◽  
Close Binaries ◽  
Helium Burning ◽  
Hydrogen Burning ◽  
Common Envelope ◽  
Central Stars

A non-negligible (∼ 15–20%) fraction of planetary nebulae is expected to be formed in close binaries in which one component fills its Roche lobe after the exhaustion of hydrogen or helium at its center. The nebula is ejected as a consequence of a frictional interaction between the stellar cores and a common envelope; the ionizing component of the central binary star may be a relatively high luminosity contracting star with a degenerate CO core, burning hydrogen or helium in a shell, or it may be a lower luminosity shell hydrogen-burning star with a degenerate helium core or a core helium-burning star. Even more exotic ionizing central stars are possible. Once the initial primary has become a white dwarf or neutron star, the secondary, after exhausting central hydrogen, will also fill its Roche lobe and eject a nebular shell in a common envelope event. The secondary becomes the ionizing star in a tight orbit with its compact companion. In all, there are roughly twenty different possibilities for the make-up of binary central stars, with the ionizing component being a post asymptotic giant branch star with a hydrogen- or helium-burning shell, a CO dwarf, a core helium-burning star, a shell helium-burning star with a degenerate CO core, a shell hydrogen-burning star with a degenerate helium core, or a helium degenerate dwarf, while its companion is a main sequence star, a CO degenerate dwarf, a helium star, a helium degenerate dwarf, or a neutron star. We estimate the occurrence frequency of several of these types and comment on the prior evolutionary history of 4 observed binary central stars.

scholarly journals Evolutionary Tracks for Central Stars of Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 463-472 ◽  
Author(s):  
Detlef Schönberner
Keyword(s):  
Mass Loss ◽  
White Dwarf ◽  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Helium Burning ◽  
Hydrogen Burning ◽  
Stellar Envelope ◽  
Thermal Pulse ◽  
Pulse Cycle ◽  
Central Stars

Our understanding of the evolution of Central Stars of Planetary Nebulae (CPN) has made considerable progress during the last years. This was possible since consistent computations through the asymptotic giant branch (AGB), with thermal pulses and (in some cases) mass loss taken into account, became available (Schönberner, 1979, 1983; Kovetz and Harpaz, 1981; Harpaz and Kovetz, 1981; Iben, 1982, 1984; Wood and Faulkner, 1986). It turned out that the evolution depends very sensitively on the inital conditions on the AGB. More precisely, the evolution of an AGB remnant is a function of the phase of the thermal-pulse cycle during which this remnant was created on the tip of the AGB by the planetary-nebula (PN) formation process (Iben, 1984, 1987). This was first shown by Schönberner (1979), and then fully explored by Iben (1984). In short, two major modes of PAGB evolution to the white dwarf stage are possible, according to the two main phases of a thermally pulsing AGB star: the hydrogen-burning or helium-burning mode. If, for instance, the PN formation, i.e. the removal of the stellar envelope by mass loss, happens during a luminosity peak that follows a thermal pulse of the helium-burning shell, the remnant leaves the AGB while still burning helium as the main energy supplier (Härm and Schwarzschild, 1975). On the other hand, PN formation may also occur during the quiescent hydrogen-burning phase on the AGB, and the remnant continues then to burn mainly hydrogen on its way to becoming a white dwarf.

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 Low Mass Wolf-Rayet Stars: Theory

1982 ◽  
Vol 99 ◽  
pp. 413-422 ◽  
Author(s):  
Alvio Renzini
Keyword(s):  
Massive Stars ◽  
Asymptotic Giant Branch ◽  
Intermediate Mass ◽  
Helium Burning ◽  
Hydrogen Burning ◽  
Intermediate Mass Stars ◽  
Low Mass ◽  
Chandrasekhar Limit ◽  
Central Stars ◽  
Evolutionary Product

It is well known that the Wolf-Rayet phenomenon is not restricted to some bright and massive stars, presumably in their core hydrogen-burning or helium-burning phase, but that it is also encountered among the central stars of some planetary nebulae (PNe). The PN nuclei are generally regarded as the evolutionary product of low and intermediate mass stars (with initial masses M.1 below ∼5 M⊙), which have lost most of their hydrogen-rich envelope during the so-called Asymptotic Giant Branch (AGB) phase. Correspondingly, their present mass cannot exceed the Chandrasekhar limit (∼1.4 M⊙), and their internal structure consists of a highly degenerate carbon-oxygen core containing most of the stellar mass, surrounded by an intershell region of mass ΔMCSH, and by a very low-mass envelope (Me < ∼10−3 M⊙).

scholarly journals When nature tries to trick us

2018 ◽  
Vol 619 ◽  
pp. A84 ◽  
Author(s):  
Henri M. J. Boffin ◽  
David Jones ◽  
Roger Wesson ◽  
Yuri Beletsky ◽  
Brent Miszalski ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Binary Star ◽  
Central Star ◽  
Equal Mass ◽  
Type I ◽  
Eclipsing Binary ◽  
Common Envelope ◽  
Bright Object ◽  
F Stars ◽  
Central Stars

Bipolar planetary nebulae (PNe) are thought to result from binary star interactions and, indeed, tens of binary central stars of PNe have been found, in particular using photometric time-series that allow for the detection of post-common envelope systems. Using photometry at the NTT in La Silla we have studied the bright object close to the centre of PN M 3-2 and found it to be an eclipsing binary with an orbital period of 1.88 days. However, the components of the binary appear to be two A or F stars, of almost equal mass, and are therefore too cold to be the source of ionisation of the nebula. Using deep images of the central star obtained in good seeing conditions, we confirm a previous result that the central star is more likely much fainter, located 2″ away from the bright star. The eclipsing binary is thus a chance alignment on top of the planetary nebula. We also studied the nebular abundance and confirm it to be a Type I PN.

scholarly journals Surface magnetic activity of the fast-rotating G5 giant IN Comae, central star of the faint planetary nebula LoTr 5

2019 ◽  
Vol 624 ◽  
pp. A83 ◽  
Author(s):  
Zs. Kővári ◽  
K. G. Strassmeier ◽  
K. Oláh ◽  
L. Kriskovics ◽  
K. Vida ◽  
...  
Keyword(s):  
Time Series ◽  
Differential Rotation ◽  
Planetary Nebula ◽  
Spectral Synthesis ◽  
Binary Star ◽  
Rotation Period ◽  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Stellar Surface ◽  
Average Lifetime

Context. On the asymptotic giant branch, low to intermediate mass stars blow away their outer envelopes, forming planetary nebulae. Dynamic interaction between the planetary nebula and its central progenitor is poorly understood. The interaction is even more complex when the central object is a binary star with a magnetically active component, as is the case for the target in this paper. Aims. We aim to quantify the stellar surface activity of the cool binary component of IN Com and aim to explain its origin. In general, we need a better understanding of how central binary stars in planetary nebulae evolve and how this evolution could develop such magnetically active stars as IN Com. Methods. We present a time series of 13 consecutive Doppler images covering six months in 2017 that we used to measure the surface differential rotation with a cross-correlation method. Hitherto unpublished high-precision photometric data from 1989 to 2017 are presented. We applied Fourier-transformation-based frequency analysis to both photometry and spectra. Very high resolution (R ≈ 200 000) spectra were used to update IN Com’s astrophysical parameters by means of spectral synthesis. Results. Our time-series Doppler images show cool and warm spots coexisting with an average surface temperature contrast of −1000 K and +300 K with respect to the effective temperature. Approximately 8% of the stellar surface is covered with cool spots and ∼3% with warm spots. A consistent cool polar spot is seen in all images. The average lifetime of the cool spots is not much more than a few stellar rotations (one month), while the warm spots appear to live longer (three months) and are mostly confined to high latitudes. We found anti-solar surface differential rotation with a shear coefficient of α = −0.026 ± 0.005 suggesting an equatorial rotation period of 5.973 ± 0.008 d. We reconfirm the 5.9 day rotation period of the cool star from photometry, radial velocities, and Hα line-profile variations. A long-term V-brightness variation with a likely period of 7.2 yr is also found. It appears in phase with the orbital radial velocity of the binary system in the sense that it is brightest at highest velocity and faintest at lowest velocity, that is, at the two phases of quadrature. We redetermine [Ba/Fe], [Y/Fe], and [Sr/Fe] ratios and confirm the overabundance of these s-process elements in the atmosphere of IN Com.

scholarly journals Observations of Planetary Nebulae Haloes

2003 ◽  
Vol 209 ◽  
pp. 447-450
Author(s):  
Romano L.M. Corradi
Keyword(s):  
Mass Loss ◽  
Surface Brightness ◽  
Planetary Nebulae ◽  
Statistical Properties ◽  
Hydrogen Burning ◽  
Morphological Component ◽  
Loss Event ◽  
Central Stars

An improved database of ionized haloes around PNe has been built by adding the results of an extensive observational campaign to the data available in the literature. The new observations allowed us to discovered new haloes around CN 1-5, IC 2165, IC 2553, NGC 2792, NGC 2867, NGC 3918, NGC 5979, NGC 6578, PB 4, and possibly IC 1747.The global sample consists of 29 AGB haloes, that are believed to still contain information about the mass loss from the AGB progenitor star. Six of these haloes show a highly asymmetrical geometry that is tentatively ascribed to the interaction of the stellar outflow with the ISM.Another 5 PNe show candidate recombination haloes. These are produced by the recombination front that sets up when the stellar luminosity drops in its post-AGB evolution. The resulting, limb-brightened shell resembles a real AGB halo, but is not related to AGB any mass loss event.Double AGB haloes are found in at least 4 PNe.For 11 PNe, deep images are available, but no halo is found to a level of ≲ 10-3 the peak surface brightness of the inner nebula.These observations show us that ionized haloes are a common morphological component of PNe, being found in 70% of elliptical PNe for which adequately deep images exist. Statistical properties of the haloes are briefly discussed. Using the kinematical ages of the haloes and inner nebulae, we conclude that most of the PNe with detected haloes have hydrogen burning central stars.

scholarly journals On the evolutionary time scale of the accreting component in massive close binaries: consequences for the supernova event

1981 ◽  
Vol 59 ◽  
pp. 465-468
Author(s):  
C. Doom ◽  
J.P. De Grève
Keyword(s):  
Mass Loss ◽  
Mass Exchange ◽  
Stellar Wind ◽  
Time Scale ◽  
Roche Lobe ◽  
Close Binaries ◽  
Evolutionary Time ◽  
Hydrogen Burning ◽  
Evolutionary Time Scale ◽  
Evolutionary Scenario

AbstractThe remaining core hydrogen burning lifetime after a case B of mass exchange is computed for the mass gaining component in massive close binaries. Effects of stellar wind mass loss and mass loss during Roche Lobe OverFlow (RLOF) are included. Consequences for the evolutionary scenario are discussed.

scholarly journals Powering and Shaping Planetary Nebulae: The Physics of Common Envelopes

2015 ◽  
Vol 11 (A29B) ◽  
Author(s):  
Jason Nordhaus ◽  
David S. Spiegel
Keyword(s):  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Close Binary ◽  
Observational Constraints ◽  
Asymptotic Giant Branch Stars ◽  
Common Envelope ◽  
Accretion Rates ◽  
Binary Channels ◽  
Giant Branch Stars

AbstractThe diversity of collimated outflows in post-asymptotic-giant-branch stars and their planetary nebula progeny are often explained by a combination of close binary interactions and accretion. The viability of such scenarios can be tested by comparing kinematic outflow data to determine minimum accretion rates necessary to power observed outflows. While many binary channels have been ruled out with this technique, common envelope interactions can accommodate the current observational constraints, are potentially common, lead to a diverse array of planetary-nebula shapes, and naturally produce period gaps for companions to white dwarfs.

scholarly journals Stellar wind models of central stars of planetary nebulae

2020 ◽  
Vol 635 ◽  
pp. A173 ◽  
Author(s):  
J. Krtička ◽  
J. Kubát ◽  
I. Krtičková
Keyword(s):  
Mass Loss ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Planetary Nebulae ◽  
Terminal Velocity ◽  
Asymptotic Giant Branch ◽  
Central Stars ◽  
Loss Rates

Context. Fast line-driven stellar winds play an important role in the evolution of planetary nebulae, even though they are relatively weak. Aims. We provide global (unified) hot star wind models of central stars of planetary nebulae. The models predict wind structure including the mass-loss rates, terminal velocities, and emergent fluxes from basic stellar parameters. Methods. We applied our wind code for parameters corresponding to evolutionary stages between the asymptotic giant branch and white dwarf phases for a star with a final mass of 0.569 M⊙. We study the influence of metallicity and wind inhomogeneities (clumping) on the wind properties. Results. Line-driven winds appear very early after the star leaves the asymptotic giant branch (at the latest for Teff ≈ 10 kK) and fade away at the white dwarf cooling track (below Teff = 105 kK). Their mass-loss rate mostly scales with the stellar luminosity and, consequently, the mass-loss rate only varies slightly during the transition from the red to the blue part of the Hertzsprung–Russell diagram. There are the following two exceptions to the monotonic behavior: a bistability jump at around 20 kK, where the mass-loss rate decreases by a factor of a few (during evolution) due to a change in iron ionization, and an additional maximum at about Teff = 40−50 kK. On the other hand, the terminal velocity increases from about a few hundreds of km s−1 to a few thousands of km s−1 during the transition as a result of stellar radius decrease. The wind terminal velocity also significantly increases at the bistability jump. Derived wind parameters reasonably agree with observations. The effect of clumping is stronger at the hot side of the bistability jump than at the cool side. Conclusions. Derived fits to wind parameters can be used in evolutionary models and in studies of planetary nebula formation. A predicted bistability jump in mass-loss rates can cause the appearance of an additional shell of planetary nebula.

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