scholarly journals Challenges faced by current Galactic planetary nebula surveys

2016 ◽  
Vol 12 (S323) ◽  
pp. 11-19
Author(s):  
David J. Frew
Keyword(s):  
Planetary Nebula ◽  
Time Interval ◽  
Important Goal ◽  
Satellite Mission ◽  
Galactic Population ◽  
Multi Wavelength ◽  
Evolutionary Pathways ◽  
Optical Surveys ◽  
Central Stars ◽  
Galactic Planetary Nebula

AbstractDetermining the demographics of the Galactic planetary nebula (PN) population is an important goal to further our understanding of this intriguing phase of stellar evolution. The Galactic population has more than doubled in number over the last 15 years, particularly from narrowband Hα surveys along the plane. In this review I will summarise these results, with emphasis on the time interval since the last IAU Symposium. These primarily optical surveys are not without their limitations and new surveys for PNe in the infrared similarly face a number of challenges. I will discuss the need for multi-wavelength approaches to discovery and analysis. The desire to have accurate volume-limited samples of Galactic PNe at our disposal is emphasised, which will be impacted with new data from the Gaia satellite mission. We need robust surveys of PNe and their central stars, especially volume-limited surveys, in order to clarify and quantify their evolutionary pathways.

scholarly journals The past, present and future of Galactic planetary nebula surveys

2011 ◽  
Vol 7 (S283) ◽  
pp. 9-16 ◽  
Author(s):  
Quentin A. Parker ◽  
David J. Frew ◽  
Agnes Acker ◽  
Brent Miszalski
Keyword(s):  
Stellar Evolution ◽  
Planetary Nebula ◽  
Galactic Plane ◽  
Narrow Band ◽  
High Sensitivity ◽  
Window Of Opportunity ◽  
The Past ◽  
Near Ir ◽  
Multi Wavelength ◽  
Galactic Planetary Nebula

AbstractOver the last decade Galactic planetary nebula discoveries have entered a golden age due to the emergence of high sensitivity, high resolution narrow-band surveys of the Galactic plane. These have been coupled with access to complimentary, deep, multi-wavelength surveys across near-IR, mid-IR and radio regimes in particular from both ground-based and space-based telescopes. These have provided powerful diagnostic and discovery capabilities. In this review these advances are put in the context of what has gone before, what we are uncovering now and through the window of opportunity that awaits in the future. The astrophysical potential of this brief but key phase of late stage stellar evolution is finally being realised.

scholarly journals Planetary Nebula Evolution Traced by Distance-Independent Parameters

1993 ◽  
Vol 155 ◽  
pp. 480-480
Author(s):  
C.Y. Zhang ◽  
S. Kwok
Keyword(s):  
Physical Properties ◽  
Mass Distribution ◽  
Planetary Nebula ◽  
Strong Support ◽  
Planetary Nebulae ◽  
Central Star ◽  
Evolution Model ◽  
The Core ◽  
Independent Parameters ◽  
Central Stars

Making use of the results from recent infrared and radio surveys of planetary nebulae, we have selected 431 nebulae to form a sample where a number of distance-independent parameters (e.g., Tb, Td, I60μm and IRE) can be constructed. In addition, we also made use of other distance-independent parameters ne and T∗ where recent measurements are available. We have investigated the relationships among these parameters in the context of a coupled evolution model of the nebula and the central star. We find that most of the observed data in fact lie within the area covered by the model tracks, therefore lending strong support to the correctness of the model. Most interestingly, we find that the evolutionary tracks for nebulae with central stars of different core masses can be separated in a Tb-T∗ plane. This implies that the core masses and ages of the central stars can be determined completely independent of distance assumptions. The core masses and ages have been obtained for 302 central stars with previously determined central-star temperatures. We find that the mass distribution of the central stars strongly peaks at 0.6 M⊙, with 66% of the sample having masses <0.64 MM⊙. The luminosities of the central stars are then derived from their positions in the HR diagram according to their core masses and central star temperatures. If this method of mass (and luminosity) determination turns out to be accurate, we can bypass the extremely unreliable estimates for distances, and will be able to derive other physical properties of planetary nebulae.

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 Structure of selected Planetary Nebulae surrounding WR-type central stars

1997 ◽  
Vol 180 ◽  
pp. 230-230
Author(s):  
S.K. Górny ◽  
K. Gȩsicki ◽  
A. Acker
Keyword(s):  
Velocity Field ◽  
Planetary Nebula ◽  
Radial Direction ◽  
Planetary Nebulae ◽  
Late Type ◽  
Computer Codes ◽  
Central Stars

The main aim of this work was to confirm that expansion of planetary nebulae surrounding Wolf-Rayet type central stars is characterized by turbulent motions or strong variations of velocity in the radial direction relative to the nucleus. Such properties have already been found in Ml-25, M3-15 and Pel-1 by Gesicki & Acker (1995). We have analyzed the photoionization structure and velocity field of the NGC 40 - a planetary nebula with late type ([WC 8]) Wolf-Rayet nucleus. The spectra of Hα and [NII] lines have been obtained with the 1.5m telescope at the Observatoire de Haute-Provence. The spectrograph Aurelie with dispersion of 5Å/mm and a 3″ circular entrance was used. The method and the details of the applied computer codes are published in Gesicki et al. (1996).

scholarly journals 35. Stellar Constitution

1985 ◽  
Vol 19 (1) ◽  
pp. 479-502
Author(s):  
A. N. Cox ◽  
D. Sugimoto ◽  
P. H. Bodenheimer ◽  
C. S. Chiosi ◽  
D. J. Faulkner ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Planetary Nebula ◽  
Massive Stars ◽  
Structure Stability ◽  
Current Interest ◽  
Late Type ◽  
Dwarf Stars ◽  
Entire Field ◽  
Stellar Formation ◽  
Central Stars

This report of Commission 35, as in past reports, consists of some details of only a few selected topics. This is necessary because a survey of the entire field of stellar formation, structure, stability, evolution, pulsation, and explosions for the three year period from mid-1981 to mid-1984 would be excessively long. Our topics here, in order from the most massive stellar classes to the least are: Massive Stars (R.M. Humphreys), Rotation in Late Type Stars (W. Benz), Helioseismology (J. Christensen-Dalsgaard), Planetary Nebula Central Stars (E.M. Sion), Pulsations in Hot Degenerate Dwarf Stars (A.N. Cox and S.D. Kawaler), and White Dwarfs (V. Weidemann). There is some overlap in the reviewing of these last three reports because the topics are very closely related. Concentration in this dying stage of stellar evolution seems appropriate because of the great current interest in these matters.

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.

scholarly journals An Updated Multi-Wavelength Radio and Optical Catalog of Quasars and Radio Galaxies

2013 ◽  
Vol 9 (S304) ◽  
pp. 238-239 ◽  
Author(s):  
Amy E. Kimball ◽  
Željko Ivezić
Keyword(s):  
Spectral Index ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Large Area ◽  
Sky Surveys ◽  
The North ◽  
Multi Wavelength ◽  
Optical Surveys ◽  
Quasars And Radio Galaxies ◽  
North Galactic

AbstractWe present a catalog of millions of radio sources, created by consolidating large-area radio and optical surveys GB6 (6cm), FIRST (20cm), NVSS (20cm), WENSS (92cm), VLSS (4m), and SDSS DR9 (optical). The region where all surveys overlap covers 3269 deg2 in the North Galactic Cap, and contains >160,000 20-cm sources, with about 12,000 detected in all five radio surveys and over one-third detected optically. Combining parameters from the sky surveys allows easy and efficient classification by radio and optical morphology and radio spectral index. The catalog is available at http://www.atnf.csiro.au/people/Amy.Kimball/radiocat.shtml.

scholarly journals Planetary nebulae with Wolf-Rayet-type central stars - II. Dissecting the compact planetary nebula M 2-31 with GTC MEGARA

2021 ◽  
Author(s):  
J S Rechy-García ◽  
J A Toalá ◽  
S Cazzoli ◽  
M A Guerrero ◽  
L Sabin ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Spectral Properties ◽  
Narrow Band ◽  
Central Star ◽  
Comprehensive Analysis ◽  
High Dispersion ◽  
Medium Resolution ◽  
First Time ◽  
Integral Field ◽  
Central Stars

Abstract We present a comprehensive analysis of the compact planetary nebula M 2-31 investigating its spectral properties, spatio-kinematical structure and chemical composition using GTC MEGARA integral field spectroscopic observations and NOT ALFOSC medium-resolution spectra and narrow-band images. The GTC MEGARA high-dispersion observations have remarkable tomographic capabilities, producing an unprecedented view of the morphology and kinematics of M 2-31 that discloses a fast spectroscopic bipolar outflow along position angles 50○ and 230○, an extended shell and a toroidal structure or waist surrounding the central star perpendicularly aligned with the fast outflows. These observations also show that the C ii emission is confined in the central region and enclosed by the [N ii] emission. This is the first time that the spatial segregation revealed by a 2D map of the C ii line implies the presence of multiple plasma components. The deep NOT ALFOSC observations allowed us to detect broad WR features from the central star of M 2-31, including previously undetected broad O vi lines that suggest a reclassification as a [WO4]-type star.

scholarly journals ORFEUS observation of the central star of NGC 6543

1997 ◽  
Vol 180 ◽  
pp. 136-136
Author(s):  
J. Zweigle ◽  
M. Grewing ◽  
J. Barnstedt ◽  
M. Gölz ◽  
W. Gringel ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Planetary Nebula ◽  
Extreme Ultraviolet ◽  
Wavelength Region ◽  
Central Star ◽  
University Of California ◽  
Satellite Mission ◽  
Ultraviolet Spectrometer ◽  
Far Ultraviolet ◽  
The University

During the ORFEUS-SPAS (Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer on the Shuttle Pallet Satellite) mission STS-51, flown in September 1993, we observed the central star of the planetary nebula NGC 6543 in the far ultraviolet (90 nm to 115 nm) wavelength region using the University of California, Berkeley spectrometer with a spectral resolution of 0.03 nm.

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