Visual Binaries; Orbital Elements

1981 ◽  
pp. 63-78
Author(s):  
Peter Van De Kamp
Keyword(s):  
Orbital Elements ◽  
Visual Binaries

scholarly journals The Reconciliation of Visual and Spectroscopic Observations of Binary Systems

1983 ◽  
Vol 62 ◽  
pp. 271-285 ◽  
Author(s):  
Alan H. Batten
Keyword(s):  
Radial Velocity ◽  
Binary Systems ◽  
Velocity Variation ◽  
Small Range ◽  
Orbital Elements ◽  
Spectroscopic Observations ◽  
Mutual Independence ◽  
Visual Binaries

AbstractThe special problems presented to the computer of orbits by radial-velocity observations of visual binaries are discussed under three heads: (i) problems caused by the small range of velocity variation, (ii) problems caused by the long periods, (iii) inconsistency between visual and spectroscopic observations. It is pointed out that radial-velocity observations, even when they are insufficient for independent determinations of orbital elements, impose constraints on possible values of those elements which may in fact be helpful to the computer of visual orbits. In particular, as is illustrated by reference to ADS 8189, even a few observations of the radial-velocity are sufficient to destroy the mutual independence of the elements e, and ω.

Blended Visual Binaries as Tests of Low Amplitude Orbit Detection and Determination Capability in Long-Focus Photographic Astrometry

1983 ◽  
Vol 62 ◽  
pp. 45-51
Author(s):  
Sarah Lee Lippincott ◽  
John L. Hershey
Keyword(s):  
Main Sequence ◽  
Orbital Motion ◽  
Orbital Elements ◽  
Detection Capability ◽  
Single Star ◽  
Planetary Mass ◽  
Residual Series ◽  
Nearby Stars ◽  
Low Amplitude ◽  
Visual Binaries

AbstractPhotocentric orbital motions from 60-year Sproul plate series are shown for three visual binaries, ζ Her, 85 Peg and Ho 296. Mass ratios of the first two pairs, which have large-amplitude blended orbits, carry internal errors at the level of one percent. Orbital elements computed independently from the blended photographic observations agree closely with the well-determined visual orbits. Ho 296 serves as a test of the Sproul plate series to detect a 20-year orbit with an amplitude of two, or one, micron. Simulations of orbital motion in single star residual series confirm this detection capability, which corresponds to planetary mass for dark objects around nearby stars. A mass-luminosity diagram of the lower main sequence is shown, including one for invisible astrometric companions.

scholarly journals On The Mass-Luminosity Relation

1998 ◽  
Vol 11 (1) ◽  
pp. 568-568
Author(s):  
P. Lampens ◽  
J. Kovalevsky ◽  
M. Froeschlé ◽  
G. Ruymaekers
Keyword(s):  
Linear Regression ◽  
Linear Regression Model ◽  
Binary Systems ◽  
Zero Point ◽  
Orbital Elements ◽  
Weighted Linear Regression ◽  
Low Mass ◽  
Absolute Magnitudes ◽  
The Impact ◽  
Visual Binaries

The new Hipparcos parallaxes and photometry are used to determine individual masses and absolute (bolometric) magnitudes for the components of nearby visual binaries with good to very good orbits. The impact on the mass-luminosity relation (MLR) in the range 0 < MBol< +7.5 mag is then evaluated. We selected 335 visual binaries within 50 pc (σπ/π < 10%) for a full error analysis of their orbits by computing the covariance matrix of the orbital elements with Pourbaix’(1994) algorithm. Using ΔHp and π, we estimated fractional and component masses as well as absolute magnitudes with theirrespective errors: 52 binary systems have relative mass errors smaller than 15%. Lutz and Kelker (1973) corrections have been applied to both datatypes. A new relation BC(Hp) as a function of Teff was obtained for the conversion to bolometric magnitudes. A doubly weighted linear regression model was applied next (Babu and Feigelson, 1996): we derived a ”mean” slope 3.82 ± 0.07 and zero point 4.94 ± 0.03 for the MLR, assuming a linear relationship. Conclusions: a) the improvement of the data on masses by Hipparcos is largely quantitative; b) not all systems agree: small fluctuations from a ”mean” MLR are found as expected from evolutionary or abundance effects; c) the break in the slope of the MLR near MBol = +7 cannot be assessed due to a lack of low-mass binaries in our sample.

scholarly journals On the component masses of visual binaries

2010 ◽  
pp. 71-80 ◽  
Author(s):  
Zorica Cvetkovic ◽  
S. Ninkovic
Keyword(s):  
Binary Stars ◽  
Total Mass ◽  
Input Data ◽  
Main Sequence ◽  
Clear Indication ◽  
Orbital Elements ◽  
High Quality ◽  
Large Dispersion ◽  
Visual Binary Stars ◽  
Visual Binaries

In the Sixth Catalog of Orbits of Visual Binary Stars we found those belonging to the Main Sequence to form a sample containing 432 visual binaries. Their total masses were obtained dynamically, i.e. they were calculated using the orbital elements and the new Hipparcos parallaxes. For the same pairs the total mass was also found astrophysically - by applying the mass-luminosity relation. The apparent magnitudes of the components were found in two different ways: by deriving them from total magnitudes and magnitude differences, and by taking their values directly from a catalogue. The results for these two approaches show no essential discrepancy. The values of total masses obtained dynamically have a large dispersion involving even completely unrealistic values. This is a clear indication that the input data are not sufficiently reliable. Nevertheless, in a large number of cases the agreement between total masses obtained by us in two different ways is quite satisfactory indicating that i) for many visual binaries, as a rule not too distant and with high-quality orbital elements, the dynamical total masses can be reliable; ii) the mass-luminosity relation yields quite satisfactory estimates for the component masses when they belong to the Main Sequence and iii) a correlation between the relative parallax error and orbit grade exists.

Artificial satellite orbit computations

1966 ◽  
Vol 25 ◽  
pp. 363-371
Author(s):  
P. Sconzo
Keyword(s):  
Artificial Satellite ◽  
Satellite Orbit ◽  
Artificial Satellites ◽  
Orbital Elements ◽  
Differential Correction ◽  
Gravitational Effects ◽  
Short Intervals ◽  
The Subject ◽  
Introductory Discussion ◽  
Orbit Computation

In this paper an orbit computation program for artificial satellites is presented. This program is operational and it has already been used to compute the orbits of several satellites.After an introductory discussion on the subject of artificial satellite orbit computations, the features of this program are thoroughly explained. In order to achieve the representation of the orbital elements over short intervals of time a drag-free perturbation theory coupled with a differential correction procedure is used, while the long range behavior is obtained empirically. The empirical treatment of the non-gravitational effects upon the satellite motion seems to be very satisfactory. Numerical analysis procedures supporting this treatment and experience gained in using our program are also objects of discussion.

Statistical results on discovered near-Earth asteroids

1999 ◽  
Vol 173 ◽  
pp. 81-86
Author(s):  
S. Berinde
Keyword(s):  
Dynamical Evolution ◽  
Minor Planet ◽  
Orbital Elements ◽  
The Earth ◽  
Near Earth Asteroids ◽  
Statistical Results

AbstractThe first part of this paper gives a recent overview (until July 1st, 1998) of the Near-Earth Asteroids (NEAs) database stored at Minor Planet Center. Some statistical interpretations point out strong observational biases in the population of discovered NEAs, due to the preferential discoveries, depending on the objects’ distances and sizes. It is known that many newly discovered NEAs have no accurately determinated orbits because of the lack of observations. Consequently, it is hard to speak about future encounters and collisions with the Earth in terms of mutual distances between bodies. Because the dynamical evolution of asteroids’ orbits is less sensitive to the improvement of their orbital elements, we introduced a new subclass of NEAs named Earth-encounter asteroids in order to describe more reliably the potentially dangerous bodies as impactors with the Earth. So, we pay attention at those asteroids having an encounter between their orbits and that of the Earth within 100 years, trying to classify these encounters.

Models of comets with strongly variable nongravitational effects

1999 ◽  
Vol 173 ◽  
pp. 381-387
Author(s):  
M. Królikowska ◽  
G. Sitarski ◽  
S. Szutowicz
Keyword(s):  
Cometary Nucleus ◽  
Spin Axis ◽  
Reactive Force ◽  
Orbital Elements ◽  
Cometary Nuclei ◽  
Short Period ◽  
Basic Parameters ◽  
Polar Radius ◽  
Cometary Activity ◽  
Nongravitational Effects

AbstractThe nongravitational motion of five “erratic” short-period comets is studied on the basis of published astrometric observations. We present the precession models which successfully link all the observed apparitions of the comets: 21P/Giacobini-Zinner, 31P/Schwassmann-Wachmann 2, 32P/Comas Solá, 37P/Forbes, and 43P/Wolf-Harrington. We used the Sekanina's forced precession model of the rotating cometary nucleus to include the nongravitational terms into equations of the comet's motion. Values of six basic parameters (four connected with the rotating comet nucleus and two describing the precession of spin-axis of the nucleus) have been determined along the orbital elements from positional observations of the comets. The solutions were derived with additional assumptions which introduce instantaneous changes of modulus of reactive force,Aand of maximum of cometary activity with respect to perihelion time. The present precession models impose some contraints on sizes and rotational periods of cometary nuclei. According to our solutions the nucleus of 21P/Giacobini-Zinner with oblateness along the spin-axis of about 0.32 (equatorial to polar radius of 1.46) is the most oblate among five investigated comets.

A Study of the Lambda Virginis System

1976 ◽  
Vol 32 ◽  
pp. 701-712
Author(s):  
D. J. Stickland
Keyword(s):  
Orbital Elements

SummaryThe orbital elements of the SB2 λ Vir have been redetermined and the earlier period of 206 days found to be correct. Both stars have been classified as Am although they exhibit rather different ve.sin i's. An abundance analysis confirms the similarity in metallicity of the two components.

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