scholarly journals Ionization correction factors for sodium, potassium, and calcium in planetary nebulae

2019 ◽  
Vol 492 (1) ◽  
pp. 950-965
Author(s):  
A Amayo ◽  
G Delgado-Inglada ◽  
J García-Rojas
Keyword(s):  
Planetary Nebulae ◽  
Emission Lines ◽  
Condensation Temperature ◽  
Correction Factors ◽  
Dust Grains ◽  
Degree Of Ionization ◽  
Sodium Potassium ◽  
First Time ◽  
Analytical Expressions ◽  
Large Grid

ABSTRACT We use a large grid of photoionization models that are representative of observed planetary nebulae (PNe) to derive ionization correction factors (ICFs) for sodium, potassium, and calcium. In addition to the analytical expressions of the ICFs, we provide the range of validity where the ICFs can be safely used and an estimate of the typical uncertainties associated with the ICFs. We improved the previous ICFs for calcium and potassium in the literature and suggest for the first time an ICF for sodium. We tested our ICFs with a sample of 39 PNe with emission lines of some ion of these elements. No obvious trend is found between the derived abundances and the degree of ionization, suggesting that our ICFs do not seem to be introducing an artificial bias in the results. The abundances found in the studied PNe range from $-2.88_{-0.22}^{+0.21}$ to −2.09 ± 0.21 in log (Na/O), from $-4.20_{-0.45}^{+0.31}$ to $-3.05_{-0.47}^{+0.26}$ in log (K/O), and from $-3.71_{-0.34}^{+0.41}$ to $-1.57_{-0.47}^{+0.33}$ in log (Ca/O). These numbers imply that some of the studied PNe have up to ∼65 per cent, 75 per cent, or 95 per cent of their Na, K, and/or Ca atoms condensed into dust grains, respectively. As expected, the highest depletions are found for calcium which is the element with the highest condensation temperature.

scholarly journals Towards an improvement in the spectral description of central stars of planetary nebulae

2018 ◽  
Vol 614 ◽  
pp. A135 ◽  
Author(s):  
W. Weidmann ◽  
R. Gamen ◽  
D. Mast ◽  
C. Fariña ◽  
G. Gimeno ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Spectral Classification ◽  
High Quality ◽  
Isaac Newton ◽  
Type Spectrum ◽  
First Time ◽  
Central Stars ◽  
Preliminary Classification

Context. There are more than 3000 known Galactic planetary nebulae, but only 492 central stars of Galactic planetary nebulae (CSPN) have known spectral types. It is vital to increase this number in order to have reliable statistics, which will lead to an increase of our understanding of these amazing objects. Aims. We aim to contribute to the knowledge of central stars of planetary nebulae and stellar evolution. Methods. This observational study is based on Gemini Multi-Object Spectrographs (GMOS) and with the Intermediate Dispersion Spectrograph (IDS) at the Isaac Newton Telescope spectra of 78 CSPN. The objects were selected because they did not have any previous classification, or the present classification is ambiguous. These new high quality spectra allowed us to identify the key stellar lines for determining spectral classification in the Morgan-Keenan (MK) system. Results. We have acquired optical spectra of a large sample of CSPN. From the observed targets, 50 are classified here for the first time while for 28 the existing classifications have been improved. In seven objects we have identified a P-Cygni profile at the He I lines. Six of these CSPN are late O-type. The vast majority of the stars in the sample exhibit an absorption-type spectrum, and in one case we have found wide emission lines typical of [WR] stars. We give a complementary, and preliminary, classification criterion to obtain the sub-type of the O(H)-type CSPN. Finally, we give a more realistic value of the proportion of CSPN that are rich or poor in hydrogen.

scholarly journals Ca and dust in Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 284-284 ◽  
Author(s):  
Kevin Volk ◽  
Harriet Dinerstein ◽  
Chris Sneden
Keyword(s):  
Gas Phase ◽  
Optical Spectrum ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Dust Grains ◽  
High Excitation ◽  
Abundance Estimates ◽  
Ngc 7027 ◽  
Dust Destruction

Under nebular conditions it is expected that the [CaII] lines at 7291.470 and 7323.880 Å should be among the strongest emission lines in the red part of the optical spectrum unless the nebula is matter bounded. The lines are observed in novae, supernovae and some symbiotic systems but the only observation of these lines in planetary nebulae (PN) is for AFGL 618 where the lines are thought to be shock-excited. While higher ionization states of Ca do produce some lines observed in a few high-excitation PN, from which gas-phase Ca abundances averaging to about 5% of solar are found, the CaII lines are not observed even in PN with massive neutral envelopes such as NGC 7027. If the Ca is depleted onto dust grains it would explain the absence of the CaII lines. However it is thought that the dust is destroyed with time in the ionized region. Any observation of the CaII lines would produce better abundance estimates and would test the extent of dust destruction that is taking place in the outer parts of the PN.

scholarly journals Line observations of the 30-Dor complex and N159A5 with the MPE imaging NIR spectrometer FAST

1991 ◽  
Vol 148 ◽  
pp. 205-206 ◽  
Author(s):  
A. Krabbe ◽  
J. Storey ◽  
V. Rotaciuc ◽  
S. Drapatz ◽  
R. Genzel
Keyword(s):  
Spatial Resolution ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Emission Lines ◽  
Resolving Power ◽  
Max Planck ◽  
First Time ◽  
Infrared Array

Images with subarcsec spatial resolution in the light of near-infrared atomic (Bry) and molecular hydrogen H2 (S(1) v=1-0) emission lines were obtained for some extended, pointlike objects in the Large Magellanic Cloud (LMC) for the first time. We used the Max-Planck-Institut für extraterrestrische Physik (MPE) near-infrared array spectrometer FAST (image scale 0.8”/pix, spectral resolving power 950) at the ESO/MPI 2.2m telescope, La Silla. We present some results on the 30-Dor complex and N159A5.

scholarly journals Characterizing global expansion evolution of the ionized matter in planetary nebulae

2016 ◽  
Vol 12 (S323) ◽  
pp. 352-353
Author(s):  
J. A. López ◽  
M. G. Richer ◽  
M. Pereyra ◽  
M. T. García-Díaz
Keyword(s):  
Galactic Halo ◽  
Evolutionary Rate ◽  
Planetary Nebulae ◽  
Central Star ◽  
Global Expansion ◽  
Kinematic Evolution ◽  
Wide Range ◽  
Model Predictions ◽  
First Time ◽  
Highly Evolved

AbstractBulk outflow or global expansion velocities are presented for a large number of planetary nebulae (PNe) that span a wide range of evolutionary stages and different stellar populations. The sample comprises 133 PNe from the Galactic bulge, 100 mature and highly evolved PNe from the disk, 11 PNe from the Galactic halo and 15 PNe with very low central star masses and low metallicities, for a total of 259 PNe. These results reveal from a statistical perspective the kinematic evolution of the expansion velocities of PNe in relation to changing characteristics of the central star’s wind and ionizing luminosity and as a function of the evolutionary rate determined by the central (CS) mass. The large number of PNe utilized in this work for each group of PNe under study and the homogeneity of the data provide for the first time a solid benchmark form observations for model predictions, as has been described by López et al. (2016).

scholarly journals A Systematic Search for Dual AGNs in Merging Galaxies (Astro-daring): III: Results from the SDSS Spectroscopic Surveys

2021 ◽  
Vol 162 (6) ◽  
pp. 276
Author(s):  
Yang-Wei Zhang ◽  
Yang Huang ◽  
Jin-Ming Bai ◽  
Xiao-Wei Liu ◽  
Jian-guo Wang ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Angular Separation ◽  
Careful Analysis ◽  
Emission Lines ◽  
Host Galaxies ◽  
Merging Galaxies ◽  
The Third ◽  
First Time ◽  
Consistent Approach

Abstract As the third installment in a series systematically searching dual active galactic nuclei (AGN) among merging galaxies, we present the results of 20 dual AGNs found by using the SDSS fiber spectra. To reduce the flux contamination from both the fiber aperture and seeing effects, the angular separation of two cores in our merging galaxy pairs sample is restricted at least larger than 3″. By careful analysis of the emission lines, 20 dual AGNs are identified from 61 merging galaxies with their two cores both observed by the SDSS spectroscopic surveys. 15 of them are identified for the first time. The identification efficiency is about 32.79% (20/61), comparable to our former results (16 dual AGNs identified from 41 merging galaxies) based on the long-slit spectroscopy. Interestingly, two of the 20 dual AGNs show two prominent cores in radio images and their radio powers show they as the radio-excess AGNs. So far, 31 dual AGNs are found by our project and this is the current largest dual AGN sample, ever constructed with a consistent approach. This sample, together with more candidates from ongoing observations, is of vital importance to study the AGN physics and the coevolution between the supermassive black holes and their host galaxies.

scholarly journals Dielectric Function of a Quantum-Confined Thin Film with a Modified Pöschel–Teller Potential

2018 ◽  
Vol 63 (12) ◽  
pp. 1109 ◽  
Author(s):  
Kh. A. Gasanov ◽  
J. I. Guseinov ◽  
I. I. Abbasov ◽  
F. I. Mamedov ◽  
D. J. Askerov
Keyword(s):  
Dielectric Permittivity ◽  
Electron Gas ◽  
Two Dimensional ◽  
Quantum Nanostructures ◽  
Carrier Scattering ◽  
Scattering Potential ◽  
Quantum Confined ◽  
Charge Carrier Scattering ◽  
First Time ◽  
Analytical Expressions

The spatial and time dispersions of the dielectric permittivity of an electron gas in quasi-two-dimensional quantum nanostructures are studied. The screening of the charge-carrier scattering potential in a quantum-confined film with a modified P¨oschel–Teller potential is considered for the first time. Analytical expressions for the dielectric permittivity are obtained.

λ-Transition to the Bose-Einstein Condensate

1995 ◽  
Vol 50 (10) ◽  
pp. 921-930 ◽  
Author(s):  
Siegfried Grossmann ◽  
Martin Holthaus
Keyword(s):  
Heat Capacity ◽  
Three Dimensional ◽  
Einstein Condensate ◽  
Einstein Condensation ◽  
Condensation Temperature ◽  
Harmonic Oscillator Potential ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Analytical Expressions ◽  
Grand Canonical

Abstract We study Bose-Einstein condensation of comparatively small numbers of atoms trapped by a three-dimensional harmonic oscillator potential. Under the assumption that grand canonical statis­tics applies, we derive analytical expressions for the condensation temperature, the ground state occupation, and the specific heat capacity. For a gas of TV atoms the condensation temperature is proportional to N1/3, apart from a downward shift of order N-1/3. A signature of the condensation is a pronounced peak of the heat capacity. For not too small N the heat capacity is nearly discon­tinuous at the onset of condensation; the magnitude of the jump is about 6.6 N k. Our continuum approximations are derived with the help of the proper density of states which allows us to calculate finite-AT-corrections, and checked against numerical computations.

scholarly journals Nebular and auroral emission lines of [Cl III] in the optical spectra of planetary nebulae

2000 ◽  
Vol 97 (9) ◽  
pp. 4551-4555 ◽  
Author(s):  
F. P. Keenan ◽  
L. H. Aller ◽  
C. A. Ramsbottom ◽  
K. L. Bell ◽  
F. L. Crawford ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Optical Spectra ◽  
Emission Lines ◽  
Auroral Emission

3D ionization structure and kinematics of NGC 2392

2011 ◽  
Vol 7 (S283) ◽  
pp. 348-349
Author(s):  
Reginald J. Dufour ◽  
Jonathan N. Sick ◽  
Patrick M. Hartigan ◽  
Richard B. C. Henry ◽  
Karen B. Kwitter ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Velocity Structure ◽  
High Spatial Resolution ◽  
Emission Lines ◽  
3 Dimensional ◽  
3D Morphology ◽  
Ionization Structure ◽  
First Time ◽  
Echelle Spectroscopy

AbstractWe discuss the 3D morphology, ionization structure, and kinematics of NGC 2392, the “Eskimo,” based on new and archival HST imagery and new long-slit echelle spectroscopy. High spatial resolution ionization maps of the nebula were made from HST WFPC2 imagery and compared with their velocity structure in various emission lines from echelle spectra taken with the 4m telescope at Kitt Peak. The imagery and spectra were then compared to map the kinematics of the nebula in several emission lines and decode the 3-dimensional morphology and ionization structure of the nebula, including that of C+2 from C III] 1909 Å for the first time.

Sign in / Sign up

Export Citation Format

Share Document