scholarly journals Probing disk inhomogeneities using spectropolarimetry in the extreme binary epsilon Aurigae

2014 ◽  
Vol 10 (S305) ◽  
pp. 293-298
Author(s):  
Kathleen Geise ◽  
Robert Stencel
Keyword(s):  
Binary System ◽  
Atomic Absorption ◽  
Linear Polarization ◽  
Single Line ◽  
High Dispersion ◽  
Spectral Features ◽  
Spectroscopic Binary ◽  
Supergiant Star ◽  
Epsilon Aurigae ◽  
Absorption Features

AbstractThe ϵ Aurigae system is a single–line spectroscopic binary system that consists of a variable F0 supergiant star and an occulting disk surrounding an unseen object, probably a B star. The eclipse occurs every 27 years and lasts for almost 2 years. Spectral features attributed to the disk exhibit line shifts due to the rotation of the disk that are easily observed in spectra. We obtained 50+ epochs of high dispersion optical spectropolarimetric data from the ESPaDOnS instrument at the Canada–France–Hawaii Telescope before, during, and after the most recent eclipse (2009–2011). We found numerous 3–sigma (or greater) linear polarization features in the spectra and associated these with atomic absorption features also present in the spectra. We observed dramatic changes to polarization and position angles with time during eclipse, particularly around 3rd contact. The increased polarization could be due to a localized increased number of scatterers.

scholarly journals Two-Spot Modeling of Synoptic Light Curves of II PEG

1983 ◽  
Vol 71 ◽  
pp. 185-188
Author(s):  
G. La Fauci ◽  
M. Rodonò
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Computer Code ◽  
Light Curves ◽  
Stellar Surface ◽  
Single Line ◽  
Relative Location ◽  
Single Spot ◽  
Spectroscopic Binary ◽  
Circular Spot

The light curve (LC) of the single-line spectroscopic binary system II Peg (K2-3, IV-III) generally shows an asymmetrical and highly variable shape (Fig.l, left). Therefore, single circular spot models can be successfully applied only to symmetric LCs, as the 1977 one by Vogt (1981). When asymmetrical or almost flat LCs develop, as appears to be the rule for II Peg, at leasts two-spot modeling is required (Bopp and Noah 1980, Dorren and Guinan 1982).From classical single-spot models (Torres and Ferraz Mello 1973, Friedman and Gurtler 1975, Bopp and Evans 1973) we have developed a computer code including two separate circular spots of different size which are allowed to assume any relative location on the stellar surface. The model is symmetric with respect to the equator. The spots are assumed to radiate as back bodies with temperature ranging from 100 to 2000 degree lower than the temperature of the unspotted photosphere (4500°K).

scholarly journals HD 50975: a yellow supergiant in a spectroscopic binary system

2014 ◽  
Vol 570 ◽  
pp. A3 ◽  
Author(s):  
J. Sperauskas ◽  
L. Začs ◽  
S. Raudeliūnas ◽  
F. Musaev ◽  
V. Puzin
Keyword(s):  
Binary System ◽  
Spectroscopic Binary ◽  
Yellow Supergiant

scholarly journals Testing Pre-Main Sequence Models with Young Binaries

2001 ◽  
Vol 200 ◽  
pp. 472-482
Author(s):  
Francesco Palla
Keyword(s):  
Binary System ◽  
Binary Systems ◽  
Main Sequence ◽  
Young Stars ◽  
System A ◽  
Spectroscopic Binary ◽  
Low Mass ◽  
Good Agreement

I will discuss several tests to gauge the accuracy of pre–main-sequence (PMS) models. Methods to determine the mass of young stars are overviewed, with emphasis on the information provided by double-lined, spectroscopic binary systems. A comparison of the dynamically determined masses with those estimated using the PMS models of Palla & Stahler (1999) is presented. Good agreement between empirical and theoretical masses is found. The analysis of the inferred ages from the isochrones shows a remarkable coevality within each binary system. A complete assessment of the accuracy of PMS tracks needs the identification of eclipsing systems of low-mass.

scholarly journals The O-type spectroscopic binary system HD 93206

1979 ◽  
Vol 83 ◽  
pp. 277-280 ◽  
Author(s):  
Nancy D. Morrison ◽  
Peter S. Conti
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Mass Loss ◽  
Massive Stars ◽  
Radial Velocities ◽  
Mass Determination ◽  
Spectroscopic Binary ◽  
The Masses

The star HD 93206 (=QZ Carinae) is a double-lined (Conti et al. 1977), eclipsing (Moffat and Seggewiss 1972) binary with a period of 6 d. Walborn (1973) classified it 09.7Ib:(n). Since the star is probably a member of the cluster Collander 228 (which is near η Carinae), its distance can be assumed to be 2600 pc. In principle, one can determine the masses of the components of HD 93206 from observations of the radial velocities and the light curve, and a spectroscopic orbit is the object of this investigation. A mass determination for an evolved star such as this one is especially important for checking recently computed evolutionary tracks with mass loss for massive stars (de Loore et al. 1977, Chiosi et al. 1978, Dearborn et al. 1978).

The O-type spectroscopic binary system HD 165921

1988 ◽  
Vol 100 ◽  
pp. 1436 ◽  
Author(s):  
Virpi S. Niemela ◽  
Nancy D. Morrison
Keyword(s):  
Binary System ◽  
Spectroscopic Binary

scholarly journals Wolf-Rayet Binaries

1980 ◽  
Vol 88 ◽  
pp. 181-185 ◽  
Author(s):  
A.F.J. Moffat ◽  
W. Seggewiss
Keyword(s):  
Magellanic Clouds ◽  
Single Line ◽  
Double Line ◽  
Spectroscopic Binary ◽  
Mass Ratios ◽  
Low Mass ◽  
First Time

An updated list of known spectroscopic double-line and single-line Galactic Wolf-Rayet binaries is presented. From this we discuss e.g. mass ratios, the binary frequency and the evidence for low-mass unseen (compact?) companions. Spectroscopic binary orbits of several WR stars in the Magellanic Clouds are noted for the first time.

scholarly journals The Deuterium Abundance in the Local Interstellar Medium

1992 ◽  
Vol 9 ◽  
pp. 455-458
Author(s):  
Jeffrey L. Linsky
Keyword(s):  
Binary System ◽  
Interstellar Medium ◽  
Line Of Sight ◽  
High Signal ◽  
Local Interstellar Medium ◽  
Signal Noise ◽  
Spectroscopic Binary

AbstractAccurate measurements of the interstellar deuterium/hydrogen ratio along different lines of sight are needed to test predictions of contemporary cosmologies. I describe our GHRS observations of the Lyman-α, 2600 Å and 2800 Å spectral regions for the spectroscopic binary system Capella, obtained with 3.57 km s resolution and high signal/noise. We are now analyzing these data to infer the column densities of H I, D I, Mg II, and Fe II along this 13 pc line of sight.

scholarly journals Constraints of a pulsation frequency on stellar parameters in the eclipsing spectroscopic binary system V577 Oph

2010 ◽  
Vol 331 (9-10) ◽  
pp. 952-955 ◽  
Author(s):  
O.L. Creevey ◽  
J. Telting ◽  
J.A. Belmonte ◽  
T.M. Brown ◽  
G. Handler ◽  
...  
Keyword(s):  
Binary System ◽  
Pulsation Frequency ◽  
Spectroscopic Binary

scholarly journals The Spectroscopic Binary System HD 158320 ( = 3U 1727 - 33?)

1975 ◽  
Vol 171 (2) ◽  
pp. 387-393 ◽  
Author(s):  
A. J. Penny ◽  
J. E. Penfold ◽  
L. A. Balona
Keyword(s):  
Binary System ◽  
Spectroscopic Binary

scholarly journals The Spectroscopic Binary Characteristics of the Mercury-Manganese Stars

1976 ◽  
Vol 32 ◽  
pp. 533
Author(s):  
G.C.L. Aikman
Keyword(s):  
Main Sequence ◽  
High Dispersion ◽  
Orbital Elements ◽  
Circular Orbits ◽  
Spectroscopic Binary ◽  
Weak Evidence ◽  
Short Period

SummaryThe 80 confirmed and suspected mercury manganese stars identified prior to 1974 and north of declination -20° have been studied from 654 high dispersion spectrograms. (2.4 - 15 Å mm-1) for velocity and degree of peculiarity. The binary frequency based on velocity variability criteria alone appears to be a normal main sequence value of about 50%, and is probably independent of the degree of enhancement of the mercury and manganese lines. New spectroscopic orbital elements are given for six systems: α And, 2 Per, κ Cnc, φ Her, HR 6620 and 46 Dra. The Hg Mn spectrosopic binaries appear to be fairly normal in their orbital characteristics, except that periods less than 3 days are conspicuously absent; there is also weak evidence for more nearly circular orbits amongst the short period Hg Mn binaries than in comparable normal binaries.

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