10 research outputs found
Contact binaries with additional components. III. The adaptive optics detections
We present results of the CFHT adaptive optics search for companions of a
homogeneous group of contact binary stars, as a contribution to our attempts to
prove a hypothesis that these binaries require a third star to become so close
as observed. In addition to companions directly discovered at separations of
>=1", we introduced a new method of AO image analysis utilizing distortions of
the AO diffraction ring pattern at separations of 0.07"-1". Very close
companions, with separations in the latter range were discovered in systems HV
Aqr, OO Aql, CK Boo, XY Leo, BE Scl, and RZ Tau. More distant companions were
detected in V402 Aur, AO Cam, V2082 Cyg. Our results provide a contribution to
the mounting evidence that the presence of close companions is a very common
phenomenon for very close binaries with orbital periods <1 day.Comment: Full Figs.4 and 5 are in
http://www.astro.utoronto.ca/~rucinski/Triples3
The 7.5 Magnitude Limit Sample of Bright Short-Period Binary Stars. I. How Many Contact Binaries Are There?
A sample of bright contact binary stars (W UMa-type or EW, and related: with
beta Lyr light curves, EB, and ellipsoidal, ELL - in effect, all but the
detached, EA), to the limit of Vmax = 7.5 magnitude is deemed to include all
discoverable short-period (P<1 days) binaries with photometric variation larger
than about 0.05 magnitude. Of the 32 systems in the final sample, 11 systems
have been discovered by the Hipparcos satellite. The combined spatial density
is evaluated at (1.02+/-0.24)x10^-5 pc^-3. The Relative Frequency of Occurrence
(RFO), defined in relation to the Main Sequence stars, depends on the
luminosity. An assumption of RFO~1/500 for MV>+1.5 is consistent with the data,
although the number statistics is poor with the resulting uncertainty in the
spatial density and the RFO by a factor of about two. The RFO rapidly decreases
for brighter binaries to a level of 1/5,000 for MV<+1.5 and to 1/30,000 for
MV<+0.5. The high RFO of 1/130, previously determined from the deep OGLE-I
sample of Disk Population W UMa-type systems towards Baade's Window, is
inconsistent with and unconfirmed by the new results. Possible reasons for the
large discrepancy are discussed. They include several observational effects,
but also a possibility of a genuine increase in the contact-binary density in
the central parts of the Galaxy.Comment: AASTeX5, 11 figures, 3 tables. Table 1 is very wide; in case of
problems send e-mail to [email protected] for a raw text versio
Neutron scattering investigation of a macroscopic single crystal of a lyotropic
Water-rich lamellar samples of the quaternary microemulsion
SDS-pentanol-water-dodecane have been prepared in form of macroscopic mono domains. The
shape is given by the quartz cuvette containing the sample, the layer
planes are parallel to the cuvette walls. Diffraction patterns and
"rocking curves” have been obtained by neutron diffraction using a
triple-axis spectrometer. Three "pseudo-Bragg peaks” have been
observed, their (relative) intensities yield a new experimental access
to estimate the product of the elastic constants resulting in a lower value than obtained from synchrotron
investigation using peak shape fitting (Roux D
Long-term photometry of variables at ESO. IV. The fourth data catalogue (1992-1994).
In this paper we present the fourth catalogue of photometric data in the Stroemgren system obtained during the period June 18, 1992-August 23, 1994 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. The catalogue is available in computer readable form at the Centre de Donnees de Strasbourg via anonymous ftp 130.79.128.5
Long-term photometry of Variables IV (Sterken+, 1995)
This is the fourth catalogue of photometric data in the Stroemgren system obtained during the period June 18, 1992 - August 23, 1994 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 3 of paper) ------------------------------ y b-y m1 c1 ------------------------------ 0.005 0.002 0.004 0.007 ------------------------------ (2 data files)
Dynamical aspects of self-organized (macro) molecular systems investigated by neutron spin-echo spectroscopy
Time-sequence Spectroscopy of Epsilon CrA: The 518 nm Mg i Triplet Region Analyzed with Broadening Functions
A pulsating star inside eta Carinae. I. Light variations, 1992-1994.
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