scholarly journals The Pulsation of M-type Miras: Multi-Epoch ISO-SWS Observations and Dynamical Models

2002 ◽  
Vol 185 ◽  
pp. 538-541 ◽  
Author(s):  
B. Aringer ◽  
U.G. Jørgensen ◽  
F. Kerschbaum ◽  
J. Hron ◽  
S. Höfner
Keyword(s):  
Time Series ◽  
Radiative Transfer ◽  
Wavelength Range ◽  
Infrared Range ◽  
Dynamical Models ◽  
Long Period ◽  
Mira Variables ◽  
Long Period Variables ◽  
Hydrostatic Model ◽  
Additional Assumptions

AbstractWe present time series of observed and synthetic ISO-SWS spectra of oxygen-rich Mira variables covering the wavelength range between 2.36 and 7.75 μm. The calculations are based on new dynamical models, which have been computed with a non-grey radiative transfer taking into account all relevant molecular opacities. It turns out that many features in the ISO spectra of cool long period variables which could not be reproduced within the framework of classical hydrostatic model atmospheres nor with grey dynamical calculations can now be understood without any additional assumptions. This is especially true for the water bands, which dominate the opacity in the infrared range of M-type Miras.

scholarly journals Gaia Data Release 2

2019 ◽  
Vol 625 ◽  
pp. A97 ◽  
Author(s):  
L. Rimoldini ◽  
B. Holl ◽  
M. Audard ◽  
N. Mowlavi ◽  
K. Nienartowicz ◽  
...  
Keyword(s):  
Time Series ◽  
High Amplitude ◽  
Rr Lyrae Stars ◽  
Long Period ◽  
Rr Lyrae ◽  
Multi Stage ◽  
Long Period Variables ◽  
Data Release ◽  
Lyrae Stars

Context. More than half a million of the 1.69 billion sources in Gaia Data Release 2 (DR2) are published with photometric time series that exhibit light variations during the 22 months of observation. Aims. An all-sky classification of common high-amplitude pulsators (Cepheids, long-period variables, δ Scuti/SX Phoenicis, and RR Lyrae stars) is provided for stars with brightness variations greater than 0.1 mag in G band. Methods. A semi-supervised classification approach was employed, firstly training multi-stage random forest classifiers with sources of known types in the literature, followed by a preliminary classification of the Gaia data and a second training phase that included a selection of the first classification results to improve the representation of some classes, before the improved classifiers were applied to the Gaia data. Dedicated validation classifiers were used to reduce the level of contamination in the published results. A relevant fraction of objects were not yet sufficiently sampled for reliable Fourier series decomposition, consequently classifiers were based on features derived from statistics of photometric time series in the G, GBP, and GRP bands, as well as from some astrometric parameters. Results. The published classification results include 195 780 RR Lyrae stars, 150 757 long-period variables, 8550 Cepheids, and 8882 δ Scuti/SX Phoenicis stars. All of these results represent candidates whose completeness and contamination are described as a function of variability type and classification reliability. Results are expressed in terms of class labels and classification scores, which are available in the vari_classifier_result table of the Gaia archive.

Dynamical Models of Circumstellar Dust Shells around Long-Period Variables

2000 ◽  
Vol 177 ◽  
pp. 377-384
Author(s):  
A. J. Fleischer ◽  
J. M. Winters ◽  
E. Sedlmayr
Keyword(s):  
Complex Interaction ◽  
Time Dependent ◽  
Circumstellar Dust ◽  
Dust Formation ◽  
Dynamical Models ◽  
Dust Shells ◽  
Long Period ◽  
Detailed Treatment ◽  
Long Period Variables ◽  
Dust Complex

We present dynamical models of circumstellar dust shells around long-period variables which include time-dependent hydrodynamics and a detailed treatment of dust formation, growth and evaporation. Important effects due to the complex interaction between the dynamics of the pulsating atmosphere and the dust complex are demonstrated.

scholarly journals Dynamical Modeling of Circumstellar Outflows

1999 ◽  
Vol 191 ◽  
pp. 187-194 ◽  
Author(s):  
Axel J. Fleischer ◽  
Jan Martin Winters ◽  
Erwin Sedlmayr
Keyword(s):  
Complex Interaction ◽  
Time Dependent ◽  
Circumstellar Dust ◽  
Dust Formation ◽  
Dynamical Models ◽  
Dynamical Modeling ◽  
Long Period ◽  
Dynamical Approach ◽  
Long Period Variables ◽  
Dust Complex

We review dynamical models of circumstellar dust shells around long-period variables which include time-dependent hydrodynamics and a detailed treatment of dust formation, growth and evaporation. Important effects caused by the complex interaction between the dynamics of the pulsating atmosphere and the dust complex which only can be revealed in the dynamical approach are summarized. Special emphasis is given to the treatment of the dust and gas opacity.

Infrared appearance of dynamical models for circumstellar dust shells around long-period variables

1995 ◽  
Vol 224 (1-2) ◽  
pp. 329-332
Author(s):  
J. M. Winters ◽  
A. J. Fleischer ◽  
E. Sedlmayr ◽  
A. Gauger
Keyword(s):  
Circumstellar Dust ◽  
Dynamical Models ◽  
Dust Shells ◽  
Long Period ◽  
Long Period Variables

scholarly journals Infrared Radial Velocity Results for Long Period Variables

1995 ◽  
Vol 155 ◽  
pp. 399-400
Author(s):  
Kenneth H. Hinkle
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Radial Velocity ◽  
Infrared Spectra ◽  
Resolution Time ◽  
Long Period ◽  
Long Period Variables ◽  
Kinematic Behaviour

AbstractHigh-resolution time-series infrared spectra have been observed for a total of 20 Long Period Variables. The stars can be placed in four groups with distinct kinematic behaviour.

Long Period Variables in Local Group dwarf Irregular Galaxies

2018 ◽  
Vol 14 (S343) ◽  
pp. 472-473
Author(s):  
John Menzies
Keyword(s):  
Small Group ◽  
Near Infrared ◽  
Local Group ◽  
Long Period ◽  
Mira Variables ◽  
Irregular Galaxies ◽  
Long Period Variables ◽  
Ngc 6822 ◽  
Dwarf Irregular Galaxies

AbstractThe long-term SAAO survey of Local Group galaxies in the near-infrared (JHKs) has included five dwarf irregulars (dIrr), namely, NGC 6822, IC 1613, WLM, Sgr dIG and NGC 3109. We have found long-period (Mira) variables in all of them. Most of the Miras, which follow a linear LMC period-luminosity (PL) relation well, are carbon-rich. A small group of oxygen-rich Miras are brighter than the linear PL relation predicts, presumably because they are undergoing hot-bottom burning (HBB).

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