The 3D Distribution of Long-period Mira Variables in the Galactic Disk

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.

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Constraints for Cataclysmic Binary Evolution as Derived from Space Distributions

International Astronomical Union Colloquium ◽

10.1017/s0252921100088710 ◽

1984 ◽

Vol 80 ◽

pp. 363-385

Author(s):

H. W. Duerbeck

Keyword(s):

Stellar Populations ◽

Recurrence Time ◽

Type I ◽

Symbiotic Stars ◽

Late Type ◽

Dwarf Novae ◽

Space Density ◽

Long Period ◽

Mira Variables ◽

Cataclysmic Binaries

AbstractSpace densities and galactic z-distributions of novae, recurrent novae, dwarf novae and symbiotic stars are newly determined and discussed in the context of earlier determinations. The data are then compared with the distributions of single and binary stars of possibly related types (late type giants, Mira variables, Algol systems, W UMa systems).Novae and dwarf novae have similar distributions, those of fairly young stellar populations. The observed space density of potential novae (novalike objects) indicates that the mean recurrence time of novae might be as small as a few hundred years, which leads, with given nova shell masses and mass transfer rates in the minimum stage, to a secular decrease of the masses of the components undergoing nova outbursts.Recurrent novae and symbiotic stars have distributions of older stellar populations, similar to those of late type giants and Mira variables.On the basis of galactic distribution, novae and dwarf novae are closely related and may be final stages of W UMa systems, as well as progenitors of supernovae of type I. A small fraction of W UMa systems seems to belong to an older population. If evolutionary transitions between these types of stars can be substantiated, the presence of a minority of novae and dwarf novae in globular clusters and of supernovae I in elliptical galaxies can be explained.Due to the lack of sufficiently well determined space distributions of Algol binaries, the suggestion that long-period Algol systems might be the progenitors of cataclysmic binaries can as yet neither be substantiated nor refuted. A very high space density of long-period Algol systems in the solar neighbourhood is derived. The observed space density of cataclysmic binaries could be explained by the transformation of a small percentage of the long-period Algol systems by common envelope evolution.

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Long Period Variables in the Magellanic Clouds and the Galaxy

International Astronomical Union Colloquium ◽

10.1017/s0252921100117312 ◽

1993 ◽

Vol 139 ◽

pp. 192-200 ◽

Cited By ~ 1

Author(s):

S.M.G. Hughes

Keyword(s):

Mass Loss ◽

Galactic Disk ◽

Magellanic Clouds ◽

Pulsation Mode ◽

Long Period ◽

Long Period Variables ◽

The Galaxy ◽

Loss Rates

AbstractNew results (∼last two years) on mainly observational properties of Long Period Variables (LPVs) in the Magellanic Clouds and the Galaxy are reviewed. These properties include the effects of metallicity variations on their mass loss rates, the use of AGB LPVs to map the stellar distributions of the Galactic disk and bulge, and using detailed observations of nearby Miras to investigate their structure and to obtain new parallax distances, with implications for the pulsation mode of Miras.

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OH/IR stars as tracers of Galactic populations

Symposium - International Astronomical Union ◽

10.1017/s0074180900123113 ◽

1993 ◽

Vol 153 ◽

pp. 57-72 ◽

Cited By ~ 1

Author(s):

H.J. Habing

Keyword(s):

Angular Momentum ◽

Galactic Center ◽

Galactic Disk ◽

Galactic Bulge ◽

High Luminosity ◽

Rotating System ◽

Circular Orbits ◽

Long Period ◽

Ir Stars ◽

Different Populations

I discuss observable quantities of OH/IR stars and their interpretation. The strong 1612 MHz maser is found in about 1/2 of all the stars that reach the AGB and then have the following properties: they are oxygen–rich, of high–luminosity (3,000 → 30,000L⊙), vary in luminosity with a long period (P>500 d), lose mass rapidly and have a metallicity high enough to form sufficient amounts of dust (the metallicity of the LMC is probably the lowest value sufficient to produce OH/IR stars). OH/IR stars can be several Gyr old. There are at least three different populations each characterized by different galactic orbits. (1) OH/IR stars in the galactic disk on almost circular orbits; (2) OH/IR stars in the galactic bulge on orbits of lower angular momentum; (3) OH/IR stars within 150 pc from the galactic center forming a rapidly rotating system.

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Report of the Committee on the Spectra of Variable Stars

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00023762 ◽

1970 ◽

Vol 14 (1) ◽

pp. 286-291

Author(s):

M. W. Feast

Keyword(s):

Binary Systems ◽

Absolute Magnitude ◽

Variable Stars ◽

Extensive Study ◽

High Dispersion ◽

Fundamental Parameter ◽

Long Period ◽

Mira Variables ◽

The Difference

The field covered by this report overlaps particularly with the work of Commissions 29 and 45 whose reports should be consulted. I have been greatly helped by reports on Soviet work by Professor Kukarkin and Dr Boyarchuk and a bibliography of European literature by Bloch.The Sonneberg programme for determining spectral types of variables has been described by Götz and Wenzel (AN, 290, 99) and several lists have been published in MVS. Bakos is studying high dispersion spectra of a number of variables that are members of visual binary systems.Stephenson and Terrill (ApJ, 147, 148) and Houk (IB, 228) have given spectral types for a considerable number of long period variables. Terrill (AJ, 74, 413) has made an extensive study of the variation of spectrum with phase for 51 red variables. Deutsch, Keenan and Garrison have continued their extensive programme of spectral classification of Mira variables. Keenan and Dessy (ApJ, 146, 583) suggest that the relatively early spectral type of the very long period Miras (R Cen, R Nor etc.) showing double maxima indicates that the fundamental parameter is the half-period (between successive maxima). A similar conclusion (ApJ, 93, 380; MN, 125, 367) was reached earlier by others on the basis of the correlation with period of the difference between absorption and emission velocities. Feast has used K subgiant companion of U Men to derive an absolute magnitude of — 0m.5 for the Mira star. The radial velocity of the companion agrees with the absorption velocity of the variable near maximum (Obs.).

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Long Period Variables in Local Group dwarf Irregular Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318005653 ◽

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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OH/IR Stars and other IRAS Point Sources as Progenitors of Planetary Nebulae

Symposium - International Astronomical Union ◽

10.1017/s007418090013877x ◽

1989 ◽

Vol 131 ◽

pp. 359-380 ◽

Cited By ~ 1

Author(s):

H. J. Habing ◽

P. te Lintel Hekkert ◽

W.E.C.J. van der Veen

Keyword(s):

Planetary Nebulae ◽

Point Sources ◽

Agb Stars ◽

Evolutionary Sequence ◽

Centre Of Mass ◽

Long Period ◽

Mira Variables ◽

Ir Stars ◽

Galactic Population ◽

History Of

We briefly review the history of the search for progenitors of planetary nebulae starting with Shklovsky's (1956) paper. The inner structure of AGB stars (the likely progenitors) is sketched. The (l, b) distributions and the (l, V) distributions (V is the centre of mass radial velocity) of OH/IR stars and of planetary nebulae are compared; it is concluded that, grosso modo, both types of objects belong to the same galactic population and that most OH/IR stars develop ultimately into planetary nebulae. From a comparison of the properties of OH/IR stars and of Mira variables it is concluded that both are AGB stars with the OH/IR stars having developed from Mira variables. Most OH/IR stars are long period variables but the few that are not are probably transition cases -no longer AGB stars and very early planetary nebulae. It is argued that the IRAS catalog contains a large number of AGB stars without (detected) OH maser emission, but otherwise similar to OH/IR stars. An evolutionary sequence is presented from Mira's to oxygen-rich planetary nebulae. Some speculations are added on the formation of carbon stars and carbon-rich planetary nebulae.

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Structure in the radiation of the galactic disk

Symposium - International Astronomical Union ◽

10.1017/s0074180900101184 ◽

1967 ◽

Vol 31 ◽

pp. 355-356

Author(s):

R. D. Davies

Keyword(s):

Magnetic Field ◽

Galactic Disk ◽

Galactic Magnetic Field ◽

Measured Polarization

Observations at various frequencies between 136 and 1400 MHz indicate a considerable amount of structure in the galactic disk. This result appears consistent both with measured polarization percentages and with considerations of the strength of the galactic magnetic field.

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On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

Symposium - International Astronomical Union ◽

10.1017/s0074180900105480 ◽

1966 ◽

Vol 25 ◽

pp. 197-222 ◽

Cited By ~ 4

Author(s):

P. J. Message

Keyword(s):

Periodic Solution ◽

Periodic Solutions ◽

Large Amplitude ◽

Restricted Problem ◽

Small Amplitude ◽

Minor Planets ◽

Long Period ◽

Numerical Integrations ◽

Period Variations ◽

The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

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Discussion following the presentation by F. Deubner

International Astronomical Union Colloquium ◽

10.1017/s0252921100053240 ◽

1977 ◽

Vol 36 ◽

pp. 69-74

Keyword(s):

List Type ◽

The Sun ◽

Type Number ◽

Harmonic Motion ◽

Locally Excited ◽

Long Period ◽

Coherent Wave ◽

Short Period ◽

Global Modes

The discussion was separated into 3 different topics according to the separation made by the reviewer between the different periods of waves observed in the sun :1) global modes (long period oscillations) with predominantly radial harmonic motion.2) modes with large coherent - wave systems but not necessarily global excitation (300 s oscillation).3) locally excited - short period waves.

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