SEARCH FOR PERIOD CHANGES IN MIRA STARS

We reobserved in the RC and i(Sloan) bands, during the years 2020-2021, seven Mira variables in Cassiopeia, for which historical i(Sloan) light curves were available from Asiago Observatory plates taken in the years 1967-84. The aim was to check if any of

26 NEW MIRA VARIABLES FROM THE ZTF SURVEY

Open European Journal on Variable stars ◽

10.5817/oejv2021-0218 ◽

2021 ◽

pp. 1-45

Author(s):

BERNHARD KLAUS ◽

STEFAN HÜMMERICH,

Keyword(s):

Survey Data ◽

Light Curves ◽

Mira Variables ◽

Sky Survey

We have continued our search for hitherto unregistered Mira variables in publicly available sky survey data, using observations from the Zwicky Transient Facility and the information provided in the Zwicky Transient Facility Suspected Variables Catalog, which led to the discovery of 26 new Mira stars. Essential data as well as light curves and phase plots for all stars are presented.

Light curves and periods of Mira variables

Astronomy and Astrophysics Supplement Series ◽

10.1051/aas:1996292 ◽

1996 ◽

Vol 120 (2) ◽

pp. 275-282 ◽

Cited By ~ 9

Author(s):

C. Alard ◽

A. Terzan ◽

J. Guibert

Keyword(s):

Light Curves ◽

Classification of the light curves of Mira variables

Astrophysics ◽

10.1007/bf02700948 ◽

1999 ◽

Vol 42 (4) ◽

pp. 408-418 ◽

Cited By ~ 1

Author(s):

N. D. Melikian

Keyword(s):

Light Curves ◽

Infrared Observations of Symbiotic Miras

10.1017/s0252921100103136 ◽

1988 ◽

Vol 103 ◽

pp. 47-56

Author(s):

Patricia Whitelock

Keyword(s):

Main Sequence ◽

Light Curves ◽

Physical Parameters ◽

Infrared Observations ◽

Mira Variables ◽

Ir Light

AbstractSymbiotic Miras are identified by their infrared characteristics. It is shown how an understanding of the evolutionary position of normal Mira variables together with the empirically established period luminosity relation can be used to derive various physical parameters for similar objects in symbiotic systems. The pulsation periods of symbiotic Miras measured so far fall between 280 and 580 days, their ages must be in the 5–10 Gyr range while main sequence masses of the order 1 to 1.5 M⊙ are indicated. The obscuration events seen in the IR light curves of several symbiotic Miras are highlighted as potentially important and possible causes are discussed.

Light Curves of Mira Variables at 1.04 Microns

The Astrophysical Journal ◽

10.1086/151118 ◽

1971 ◽

Vol 169 ◽

pp. 63 ◽

Cited By ~ 59

Author(s):

G. W. Lockwood ◽

Robert F. Wing

Keyword(s):

Light Curves ◽

Distance to SN 1987A and the LMC

Symposium - International Astronomical Union ◽

10.1017/s0074180900118959 ◽

1999 ◽

Vol 190 ◽

pp. 549-554

Author(s):

Nino Panagia

Keyword(s):

Angular Size ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Light Curves ◽

Distance Modulus ◽

Absolute Size ◽

Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

Quasi-Periodic Oscillations in Dwarf Novae

10.1017/s0252921100073310 ◽

1979 ◽

Vol 46 ◽

pp. 77-88

Author(s):

Edward L. Robinson

Keyword(s):

Binary Systems ◽

Outer Edge ◽

Light Curves ◽

Close Binary ◽

Bright Spot ◽

Dwarf Novae ◽

Periodic Oscillations ◽

High Frequencies ◽

Short Period ◽

Typical Time

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.

The Eclipsing Binary WX Eridani

10.1017/s0252921100073656 ◽

1979 ◽

Vol 46 ◽

pp. 385

Author(s):

M.B.K. Sarma ◽

K.D. Abhankar

Keyword(s):

Light Curve ◽

Spectral Type ◽

Orbital Period ◽

Primary Component ◽

Light Curves ◽

Absorption Feature ◽

Primary Star ◽

Eclipsing Binary ◽

The Times ◽

Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

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

10.1017/s0252921100073668 ◽

1979 ◽

Vol 46 ◽

pp. 386-408 ◽

Cited By ~ 2

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

EAS Publications Series ◽

10.1051/eas/1571055 ◽

2015 ◽

Vol 71-72 ◽

pp. 249-250

Author(s):

K.H. Hinkle ◽

T. Lebzelter

Keyword(s):