No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Measurements of visual double stars with PISCO2 at the Nice 76‐cm refractor in 2016–2017
Abstract
We present relative astrometric and photometric measurements of visual double stars made in 2016–2017, with PISCO2 installed at the 76‐cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Three different techniques were used for obtaining measurements: Lucky Imaging, Speckle Interferometry and the direct vector autocorrelation (DVA) method. From our observations of 1,510 multiple stars, we obtained 2,918 new measurements with angular separations in the range 0″.1–20″ and an average accuracy of . The mean error on the position angles is 1°.1. Most of the position angles were determined without the usual 180° ambiguity with the application of the DVA technique and/or by inspection of the Lucky images or the long integration files. We managed to routinely monitor faint systems () with large magnitude differences (up to ). We have thus been able to measure six systems containing red dwarf stars that had been poorly monitored since their discovery, from which we estimated the stellar masses thanks to Gaia measurements. We also measured the magnitude difference of the two components of 593 double stars with a mean error of 0.1 mag. Thanks to good seeing images and with the use of high‐contrast numerical filters, we have also been able to obtain 46 measurements with an angular separation smaller than the diffraction limit of our instrumentation. Except for a few objects that have been discussed, our measurements are in good agreement with the ephemerides computed with published orbital elements, even for the double stars whose separation is smaller than the diffraction limit. We also report the measurements of 205 new double stars that we found in the files obtained during the observations.
ResearchGate has not been able to resolve any citations for this publication.
We present relative astrometric and photometric measurements of visual binaries made in 2009–2010 with the 76‐cm refractor of Côte d'Azur Observatory and a pair of sensitive EMCCD ANDOR cameras. Our observing list includes optical pairs and binaries whose orbital motion is still uncertain. Three different techniques were used for obtaining measurements: Lucky Imaging, Speckle Interferometry, and the Direct Vector Autocorrelation method. From our 2,050 observations of double stars, we obtained 1,652 new measurements of the relative position of 1,792 objects, with angular separations in the range 0".1–14".1. The average accuracy is estimated at 0".02 for the angular separations and 0°.6 for the position angles. We managed to observe faint systems (m V ≈ 12) with a large magnitude difference (up to Δm V ≈ 5). We have thus been able to measure many systems containing red dwarf stars that had been poorly monitored since their discovery. We also measured the difference of magnitude of the two components of 1,143 objects with an estimated error of 0.2 mag.
The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope in 2016 and 2017 are given, totaling 2483 measurements of 1570 resolved pairs and 609 non-resolutions. We describe briefly recent changes in the instrument and observing method and quantify the accuracy of the pixel scale and position angle calibration. Comments are given on 44 pairs resolved here for the first time. The orbital motion of the newly resolved subsystem BU 83 Aa,Ab roughly agrees with its 36-year astrometric orbit proposed by J. Dommanget. Most Tycho binaries examined here turned out to be spurious. © 2018. The American Astronomical Society. All rights reserved..
Vector-autocorrelation techniques are highly suited to extracting
astrometric information from very large volumes of speckle data in near
real time, but they inherently introduce a 180-deg ambiguity in the
position-angle measurement. This can be a problem in determining the
orbital motions in binaries, so an algorithm is presented which
maintains most of the simplicity of vector autocorrelation while
removing the quadrant ambiguity. Results are provided from
absolute-quadrant determinations for 66 binary star systems first
resolved by the long-term GSU/CHARA speckle program. The algorithm is
used to eliminate the period ambiguity in the orbit of the close visual
binary ADS 9744.
Results of speckle observations at the 4.1-m SOAR telescope in 2012 (158
measures of 121 systems, 27 non-resolutions) are reported. The aim is to follow
fast orbital motion of recently discovered or neglected close binaries and
sub-systems. Here 8 previously known orbits are defined better, two more are
completely revised, and five orbits are computed for the first time. Using
differential photometry from Hipparcos or speckle and the standard relation
between mass and absolute magnitude, the component's masses and dynamical
parallaxes are estimated for all 15 systems with new or updated orbits. Two
astrometric binaries HIP 54214 and 56245 are resolved here for the first time,
another 8 are measured. We highlight several unresolved pairs that may actually
be single despite multiple historic measures, such as 104 Tau and f Pup AB.
Continued monitoring is needed to understand those enigmatic cases.
We report the discovery of visual double stars, mostly with separations between 0.3 and 1 arcsec, from a dedicated re–reduction of the Tycho data from the star mapper of the ESA Hipparcos satellite. The new doubles are combined with WDS systems identified in the Catalogue, and 1220 new doubles, to form the Tycho Double Star Catalogue, TDSC, a catalogue of absolute astrometry and , photometry for components of double and multiple star systems. We also include results for single components for systems unresolved in TDSC, and a supplement gives Hipparcos and data for 4777 additional components. The TDSC thus contains a total of entries. Cross identifications are given to WDS, HD, Hipparcos and .
We present relative astrometric and photometric measurements of visual double stars made in 2013–2015, with PISCO2 installed at the 76‐cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Most of the observations were done in 2015, but some other observations of wide couples were done in 2013–2014 (0.3% of the total of the observations). Three different techniques were used for obtaining measurements: lucky imaging, speckle interferometry and the direct vector autocorrelation method. From our observations of 2837 multiple stars, we obtained 5182 new measurements with angular separations in the range of 0.1–32 and an average accuracy of . The mean error on the position angles is 0°.8. Most of the position angles were determined without the usual 180° ambiguity with the application of the direct vector autocorrelation technique and/or by inspection of the Lucky images or the long integration files. We managed to routinely monitor faint systems () with large magnitude difference (up to ). We have thus been able to measure 21 systems containing red dwarf stars that had been poorly monitored since their discovery, from which we estimated the stellar masses thanks to Gaia measurements. We also measured the magnitude difference of the two components of 1079 double stars with an estimated error of 0.2 mag. Except for a few objects that are discussed, our measurements are in good agreement with the ephemerides computed with published orbital elements, even for the double stars whose separation is smaller than the diffraction limit. Thanks to good seeing images and with the use of high‐contrast numerical filters, we have also been able to obtain 196 measurements with an angular separation smaller than the diffraction limit of our instrumentation, and consistent with those obtained with larger telescopes. We also report measurements of the 164 new double stars that we found in the files obtained during the observations. Finally, from a study of the DR3 Gaia release, it is shown that all the objects of the Tycho Double Star Catalog that we did not resolve in 2015 are probably false detections by Tycho.
We present relative astrometric and photometric measurements of visual binaries made in 2011–2012, with PISCO2 installed at the 76‐cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as binaries whose motion is still uncertain. Three different techniques have been used for obtaining those measurements: Lucky imaging, speckle interferometry, and the direct vector autocorrelation method. From our observations of 3,136 multiple stars, we obtained 3,568 new measurements with angular separations in the range of 0″.1–10″ and an average accuracy of 0″.016. The mean error on the position angles is 1°.7. Most of the position angles were determined without the usual 180° ambiguity with the application of the direct vector autocorrelation technique and/or by inspection of the Lucky images or the long integration files. We managed to routinely monitor faint systems (mV ≈ 9–11) with large magnitude difference (up to ΔmV ≈ 5). We have thus been able to measure many systems containing red dwarf stars that had been poorly monitored since their discovery. We also measured the magnitude difference of the two components of 326 binaries with an estimated error of 0.2 mag. Except for a few objects that have been discussed, our measurements are in a good agreement with the ephemerides computed with published orbital elements, even for the binaries closer than the diffraction limit. Thanks to good seeing images and with the use of high‐contrast numerical filters, we have also been able to obtain 196 measurements with an angular separation smaller than the diffraction limit of our instrumentation, and consistent with those obtained with larger telescopes. We also obtained new measurements of the 15th magnitude multiple system CON37, and discovered a faint new double star in its vicinity. Finally, we report 47 measurements of 28 new binaries found during our observations.
We present relative astrometric and photometric measurements of visual
binaries made in 2008, with the 76-cm refractor of Côte d'Azur
Observatory. Our observing list contains orbital couples as well as
binaries whose motion is still uncertain. Three different techniques
were used for obtaining measurements: Lucky imaging, speckle
interferometry and the Direct Vector Autocorrelation method. We obtained
2420 new measurements of the relative position of 2225 objects, with
angular separations in the range 0.07 arcsec-11.5 arcsec, and an average
accuracy of 0.02 arcsec. The mean error on the position angles is 0.6 deg.
We managed to observe faint systems (m_V ≈ 12) with large magnitude
difference (up to Δ m_V ≈ 5). We have thus been able to measure
many systems containing red dwarf stars that had been poorly monitored
since their discovery. We also measured the difference of magnitude of
the two components of 376 objects with an estimated error of 0.1 mag.
Finally, we provide a list of 33 newly discovered components of multiple
or binary systems, which is a significant complement to our GII catalog.
} %% end abstract
Table 2 is available at the CDS via
http://cdsarc.u-strasbg.fr/cgi-bin/qcat?J/AN/333/727
Class I: Definitive Orbits, Class II: Reliable Orbits, Class III: Preliminary Orbits, Class IV: Parabolic Orbits, Class V: Indeterminate Orbits
New double stars discovered by R. Gili with PISCO2” IAU Commission G1 - Double Stars Inf
- R Gili
2023 REDUC data processing software
- F Losse
Sixth catalogue of orbits of visual binary stars (OC6)
- R A Matson
- S J Williams
- W I Hartkopf