scholarly journals Multiwavelength Period–Luminosity and Period–Luminosity–Color Relations at Maximum Light for Mira Variables in the Magellanic Clouds

2019 ◽  
Vol 884 (1) ◽  
pp. 20 ◽  
Author(s):  
Anupam Bhardwaj ◽  
Shashi Kanbur ◽  
Shiyuan He ◽  
Marina Rejkuba ◽  
Noriyuki Matsunaga ◽  
...  
Keyword(s):  
Magellanic Clouds ◽  
Maximum Light ◽  
Mira Variables

scholarly journals Mira Variables: Theory versus Observation

1995 ◽  
Vol 155 ◽  
pp. 127-138 ◽  
Author(s):  
P.R. Wood
Keyword(s):  
Fundamental Mode ◽  
Magellanic Clouds ◽  
The Other ◽  
Solar Neighbourhood ◽  
Angular Diameter ◽  
Pulsation Velocity ◽  
Multiple Modes ◽  
Pulsation Mode ◽  
Mira Variables ◽  
Theory Versus

AbstractThe identification of the mode of pulsation of Mira variables remains a major problem. Recent angular diameter measurements of solar neighbourhood Miras suggest large radii consistent with first overtone pulsation. On the other hand, the pulsation velocity amplitudes of Mira variables point to fundamental mode pulsation. There is some marginal evidence from multiple modes in Miras that the prime pulsation mode is the first overtone, while distinct (K,logP) sequences in the Magellanic Clouds point to the Miras being fundamental mode pulsators. The above confusing evidence is presented and discussed. Finally, the (K,logP) relations in the SMC and LMC are compared in order to determine if there is any metallicity dependence.

scholarly journals Local Group Galaxies in the Infrared

2010 ◽  
Vol 6 (S277) ◽  
pp. 34-36
Author(s):  
John Menzies
Keyword(s):  
South African ◽  
Local Group ◽  
Magellanic Clouds ◽  
Mira Variables ◽  
Dwarf Spheroidals ◽  
Distance Indicators ◽  
Infrared Survey

AbstractA survey has been conducted of Local Group galaxies with the Japanese/South African Infrared Survey Facility at SAAO, Sutherland. A number of Mira variables have been discovered in four dwarf spheroidals, which provides an opportunity to test the usefulness of these stars as distance indicators in galaxies beyond the Magellanic Clouds. These Miras are found to follow the same period-luminosity relation as in the LMC, provided bolometric magnitudes are used.

Novae in the Magellanic Clouds

1979 ◽  
Vol 46 ◽  
pp. 96-101
Author(s):  
J.A. Graham
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
University Of Michigan ◽  
The Past ◽  
Spectroscopic Information ◽  
Objective Prism ◽  
The University ◽  
Small Cloud ◽  
Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).

Polarimetric Observations of Red Variables: A Study of Gas and Particle Interactions

1979 ◽  
Vol 46 ◽  
pp. 386-408 ◽  
Author(s):  
G. V. Coyne ◽  
I. S. McLean
Keyword(s):  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Absorption And Emission ◽  
Mira Variables ◽  
Stellar Photosphere ◽  
Regular Variable ◽  
Red Supergiants ◽  
Balmer Lines

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

The MOLspheres of Mira Variables

2015 ◽  
Vol 71-72 ◽  
pp. 249-250
Author(s):  
K.H. Hinkle ◽  
T. Lebzelter
Keyword(s):  
Mira Variables

scholarly journals Molecules in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 415-420 ◽  
Author(s):  
R. S. Booth ◽  
Th. De Graauw
Keyword(s):  
High Resolution ◽  
Molecular Clouds ◽  
Short Review ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Giant Molecular Clouds ◽  
Interstellar Molecules ◽  
First Time ◽  
Excitation Conditions

In this short review we describe recent new observations of millimetre transitions of molecules in selected regions of the Magellanic Clouds. The observations were made using the Swedish-ESO Submillimetre Telescope, SEST, (Booth et al. 1989), the relatively high resolution of which facilitates, for the first time, observations of individual giant molecular clouds in the Magellanic Clouds. We have mapped the distribution of the emission from the two lowest rotational transitions of 12CO and 13CO and hence have derived excitation conditions for the molecule. In addition, we have observed several well-known interstellar molecules in the same regions, thus doubling the number of known molecules in the Large Magellanic Cloud (LMC). The fact that all the observations have been made under controlled conditions with the same telescope enables a reasonable intercomparison of the molecular column densities. In particular, we are able to observe the relative abundances among the different isotopically substituted species of CO.

scholarly journals Discovery of Infrared Stars in Globular Clusters in the Magellanic Clouds and Their Light Variations

1998 ◽  
Vol 11 (1) ◽  
pp. 395-395
Author(s):  
S. Nishida ◽  
T. Tanabé ◽  
S. Matsumoto ◽  
T. Onaka ◽  
Y. Nakada ◽  
...  
Keyword(s):  
Mass Loss ◽  
Globular Clusters ◽  
Main Sequence ◽  
Near Infrared ◽  
Magellanic Clouds ◽  
Infrared Light ◽  
Agb Stars ◽  
Dust Shells ◽  
Infrared Stars ◽  
Infrared Survey

A systematic near-infrared survey was made for globular clusters in the Magellanic Clouds. Two infrared stars were discovered in NGC419 (SMC) and NGC1783 (LMC). NGC419 and NGC1783 are well-studied rich globular clusters whose turn-off masses and ages are estimated MTO ~ 2.0 Mʘ and т ~1.2 Gyr for NGC419, and MT0 ~ 2.0 Mʘ and т ʘ 0.9 Gyr for NGC1783, respectively. The periods of the infrared light variations were determined to be 540 dfor NGC419IR1 and to be 480 d for NGC1783IR1, respectively. Comparison of the measurements with the period—if magnitude relation for carbon Miras in the LMC by Groenewegen and Whitelock(1996) revealed that the Kmagnitudes of the infrared stars were fainter by about 0.3 — 0.8 magnitude than those predicted by the P — K relation. This deviation can be explained if the infrared stars are surrounded by thick dust shells and are obscured even in the K band. The positions of NGC419IR1and NGC1783IR1 on the P — K diagram suggest that AGB stars with the main sequence masses of about 2 Mʘ start their heavy mass-loss when P ʘ 500 d.

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