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Scientific results

Improving the Orbits of Four Visual Binaries Using Gaia DR2 Data and Observations with the 26-inch Refractor of Pulkovo Observatory.

Romanenko L. G., Izmailov I. S.

Central Astronomical Observatory at Pulkovo, Russian Academy of Sciences, Saint Petersburg, Russia

We use a modified method of the apparent motion parameters (AMP), in which the initial data from the Gaia DR2 catalog are not only high-precision coordinates, parallaxes, and radial velocities of the components of the studied wide binary stars, but are also their proper motions. The coincidence of the AMP orbits obtained both from the Gaia DR2 data and from the Pulkovo series from 1960-2019 leads to an orbit that is unambiguous in terms of an ascending node. The results for improving the orbits of such visual binaries of the Pulkovo research program as ADS 246, 2757, 10386, and 12169 are presented. Orbits (with periods of 1226, 1075, 4500, and 4900 years), orbital orientation parameters in the Galaxy coordinate frame, and the masses of these systems are obtained (0.59+/-0.05, 1.7+/-0.3, 1.7+/-0.4, and 2.25+/-0.5 solMass). It is shown that dense homogeneous series of ground-based observations, such as CCD observations with the 26-inch refractor of the Pulkovo Observatory, do not lose their relevance, serve as the basis for identifying the best solution based on both Gaia data and our own observations, and should be continued. It was also shown that the Thiele-Innes method is not suitable for determining the orbits of binary stars with a separation of more than 100 AU.

DOI: 10.1134/S1063772921030021

Astronomy Reports, 2021, Vol. 65, No. 3, pp. 209–223. © Pleiades Publishing, Ltd., 2021.
Russian text published in Astronomicheskii Zhurnal, 2021, Vol. 98, No. 3, pp. 239–254.


Full text (english)
Full text (russian)

Astrometric observations of visual double stars
at Pulkovo observatory
with 26-inch refractor during 2014 - 2019.

Igor Izmailov1, Aleksey Rublevsky2, Arina Apetyan1
1Central Astronomical Observatory at Pulkovo, Russian Academy of Sciences, Saint Petersburg, Russia
2Crimean Astrophysical Observatory, Russian Academy of Sciences, Crimea, Nauchny Russia

We present 18,365 astrometric observations of 290 visual binaries obtained with the 26-inch refractor of Pulkovo Observatory during 2014–2019. The separation between components is from 1".3 to 37" with a median value of 4".8. For a single observation, the mean separation error is 0".013, and the mean position angle error is 0o.44/ρ, where ρ is an angular distance in arcseconds. We compare the observations of sample stars with the data from the Gaia DR2 catalog and the results of the ground-based observations performed with other telescopes.

DOI: 10.1002/asna.202013815

Keywords: binaries: visual; methods: observational. Publication:
Astronomische Nachrichten, Volume 341, Issue 8, pp. 762-769, 2020


Full text

Orbits of 451 wide visual double stars.

Izmailov I. S.

Central Astronomical Observatory of RAS at Pulkovo

Based on positional observations, we have determined the orbits of 130 visual double stars for the first time and improved the orbits of 321 stars. The histogram of eccentricities for all of the derived orbits corresponds to the relation f = 2e. The period distribution has two pronounced maxima at P ≈ 200 and ≈ 550 yr. The ephemeris relative positions and their errors have been calculated for the next three years.
DOI: 10.1134/S106377371901002X

Keywords: double and multiple stars, orbits. Publication:
Astronomy Letters, Volume 45, N1, pp.30-38,2019

The program for calculating orbits by Thiele-Innes method:

The input file for this program is 'input.txt'.
The format of this file is as follows:
1 Date of the observation
2 Position angle, equinox 2000.0
3 Angular separation
Output file is 'output.txt'.

Program 'Precess' takes into account the precession using the formula:

Δθ=0o.00556 sin α (2000-t) sec δ

The data source is file 'source.txt'
The first line must have a WDS designation, based on J2000 coordinates. It prepares a file for programs tilin132.
Download 'Precess_win32'
Download 'Precess_win64'

The program 'err6' is designed to calculate a set of orbits.
It is use file 'output.txt' from tilin132.
Download 'Err6_win32'
Download 'Err6_win64'

May Wide Triple Star Systems Be Flat?

Izmailov, I. S.; Roshchina, E. A.

We studied the possibility of flat solutions for triple systems. For the analysis we chose the systems of type I: a close pair with a distant companion, with known orbits where the satellite shows significant relative motion. We calculated two variants of the orbit for the wide pairs — with the condition of coplanarity of orbits of close and wide pair, and without it. If the sum of squared residuals for orbit determined with the condition is not increased, it may be assumed that the system is flat. Among reviewed fifteen triple systems, the following ones may be flat: WDS 20474+3629, 00321+6715, 01198-0031, 02291+6724, 05239-0052, 06003-3102, 08122+1739, 10370-0850, 17066+0039. Other systems are not able to have the coplanar orbits of wide and close pair: WDS 8592+4803, 01350-2955, 02022+3643, 04400+5328 and 08468+0625. Three of them have a retrograde motion.

Stars: From Collapse to Collapse, Proceedings of a conference held at Special Astrophysical Observatory, Nizhny Arkhyz, Russia 3-7 October 2016. Edited by Yu. Yu. Balega, D. O. Kudryavtsev, I. I. Romanyuk, and I. A. Yakunin. San Francisco: Astronomical Society of the Pacific, 2017, p.364

Full Printable Article (PDF)

Astrometric CCD observations of visual double stars at Pulkovo observatory.

Izmailov I. S., Khovritcheva M. L., Khovritchev M. Yu., Kiyaeva O. V., Khrutskaya E. V., Romanenko L. G., Grosheva E. A., Maslennikov K. L., Kalinichenko O. A.

Central Astronomical Observatory of RAS at Pulkovo

We present the results of 3489 astrometric CCD-measurements of 361 visual double stars performed with the 26-inch refractor of the Pulkovo observatory in 2003 - 2007. Angular separations (rho) and position angles (theta) are provided. Mean values of standard errors are 0".009 in rho and 0.40(deg)/rho in theta, where rho is the separation in arcseconds.

Astronomy Letters, Volume 36, Issue 5, pp.349-354,2010

Data of observations:

Astrometric Observations of Visual Binaries Using 26-inch Refractor during 2007–2014 at Pulkovo

I. S. Izmailov and E. A. Roshchina

Central Astronomical Observatory of RAS at Pulkovo

We present the results of 15 184 astrometric observations of 322 visual binaries carried out in 2007–2014 at Pulkovo observatory. In 2007, the 26-inch refractor (F = 10 413 mm, D = 65 cm) was equipped with the CCD camera FLI ProLine 09000 (FOV 12´×12´ , 3056×3056 pixels, 0.238 arcsec/pixel). Telescope automation and weather monitoring system installation allowed us to increase the number of observations significantly. Visual binary and multiple systems with an angular distance in the interval 1″.1–78″.6 with 7″.3 on average were included in the observing program. The results were studied in detail for systematic errors using calibration star pairs. There was no detected dependence of errors on temperature, pressure, and hour angle. The dependence of the 26-inch refractor’s scale on temperature was taken into account in calculations. The accuracy of measurement of a single CCD image is in the range of 0″.0005 to 0″.289, 0″.021 on average along both coordinates. Mean errors in annual average values of angular distance and position angle are equal to 0″.005 and 0°.04 respectively. The results are available here http://izmccd.puldb.ru/vds.htm and in the Strasbourg Astronomical Data Center (CDS). In the catalog, the separations and position angles per night of observation and annual average as well as errors for all the values and standard deviations of a single observation are presented. We present the results of comparison of 50 pairs of stars with known orbital solutions with ephemerides.

Astrophysical Bulletin, Volume 71, Issue 2, pp.225-231, 2016
Article on the journal's website.[in Russian]

Data of observations:

Pulkovo Observatory
SAI Moscow University
Institute of Applied Astronomy of RAS
Institute of astronomy of RAS
AO of St. Petersburg state University
CDS, Strasbourg
Nikolaev Observatory
MAO, NAS of Ukraine

© Igor Izmailov