scholarly journals SZ Lyn: New pulsational and orbital elements based on old and recent photometric observations

2007 ◽  
Vol 145 ◽  
pp. 47-47
Author(s):  
K. D. Gazeas
Keyword(s):  
Orbital Elements ◽  
Photometric Observations

Verification of the V-type asteroids rotation distribution outside Vesta family

2020 ◽  
Author(s):  
Volodymyr Troianskyi ◽  
Keyword(s):  
Numerical Modelling ◽  
Thermal Parameters ◽  
Orbital Elements ◽  
Main Belt ◽  
Preliminary Results ◽  
Yarkovsky Effect ◽  
Photometric Observations

<p align="justify">The main objective of the study is the verification of the V-type rotation distribution. Though numerical modelling, Nesvorny et al. <span lang="en-US">(</span>2008<span lang="en-US">)</span> showed that asteroids can migrate <span lang="en-US">through</span> Yarkovsky effect and resonaces outside the boundaries of the Vesta family. In particular they found that objects which end up in the scattered resonances region (so-called Cell I, defined by orbital elements 2.2 AU < a < 2.3 AU, 0.05 < e < 0.2, 0 < i deg < 10 deg) typically have retrograde rotation and thermal parameters that maximize <span lang="en-US">the</span> Yarkovsky drift. Consequently, most of the V-types in Cell I should be retrograde rotating. Similarly showed that asteroids migrating to the low inclination region (Cell II defined by 2.32 AU < a < 2.48 AU, 0.05 < e < 0.2, 2 deg < i < 6 deg) should be predominantly rotating prograde (60% of objects).</p> <p align="justify">We perform photometric observations and determine spins and shapes of V-type objects in Cell I and II to verify the predicted statistics of sense of rotation. Finding significantly <span lang="en-US">un-matching</span> statistics for rotational properties may strengthen the idea that there may be fragments of other (than Vesta) differentiated planetesimals in the inner main belt. We show preliminary results for the first few asteroids in Cell I and II.</p>

scholarly journals The Absolute Dimensions and Masses of IQ Persei

1985 ◽  
Vol 111 ◽  
pp. 389-389
Author(s):  
Claud H. Lacy
Keyword(s):  
Cross Correlation ◽  
Main Sequence ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Apsidal Motion ◽  
Orbital Elements ◽  
Photometric Observations ◽  
The Absolute ◽  
Motion Period ◽  
Absolute Dimensions

High signal-to-noise ratio spectrometric observations of the large light-ratio eclipsing binary IQ Per (B7 + A2) have been obtained with the coudé Reticon spectrograph of the 2.7 m reflector at McDonald Observatory. Absorption lines of the secondary are seen at the 4481 Å MgII line and the 4549 Å TiII + FeII blend. Radial velocities of both components have been measured by cross-correlation techniques and spectroscopic orbits have been computed. The fitted orbits have an eccentricity (0.075 ± 0.007) that is consistent with the photometric orbit of Hall, Gertken and Burke (1970). Young's (1975) “provisional” estimate of K2 is about 14% too small. Absolute dimensions and masses have been computed from Hall et al.'s (1970) photometric orbit and the new spectroscopic orbit. Additionally, V-R photometric observations obtained by M. Frueh at McDonald Obs. have been analysed by Popper with light curve synthesis techniques (WINK and EBOP). The relative radii of the new photometric orbits differ by less than 2% from the previous orbits, and the other orbital elements also show excellent agreement. The absolute dimensions and masses are (3.51 ± 0.04m⊙, 2.46 ± 0.04 R⊙) for the primary and (1.73 ± 0.02m⊙, 1.50 ± 0.03 R⊙) for the secondary. Both stars are near the zero-age main sequence. The value of ω has changed significantly between the epoch of Hall, Gertken, and Burke's (1970) observations and my own due to apsidal motion. The apsidal motion period is estimated to be in the interval 90 ≤ τ ≤ 180 yr.

Shape models and dynamical properties of basaltic asteroids outside the dynamical Vesta family

2021 ◽  
Author(s):  
Volodymyr Troianskyi ◽  
Dagmara Oszkiewicz ◽  
Anna Marciniak ◽  
Pawel Kankiewicz ◽  
Dora Fohring ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Parent Body ◽  
Thermal Parameters ◽  
Orbital Elements ◽  
Main Belt ◽  
Preliminary Results ◽  
Shape Models ◽  
Photometric Observations ◽  
Current Location ◽  
Dynamical Properties

<p>Through numerical modeling, Nesvorny et al. (2008) showed that asteroids can migrate due to Yarkovsky drift and resonances to outside of the boundaries of the Vesta family. In particular, they found that objects which end up in the scattered resonances region (so-called Cell I, defined by orbital elements 2.2 AU < a < 2.3 AU, 0.05 < e < 0.2, 0 < i deg < 10 deg) typically have retrograde rotations and thermal parameters that maximize Yarkovsky drift rates. These autors also showed, that asteroids migrating to the low inclination region (Cell II defined by 2.32 AU < a < 2.48 AU, 0.05 < e < 0.2, 2 deg < i < 6 deg) should be predominantly prograde rotators.</p> <p>We performe photometric observations and determine spins and shapes of V-type objects in Cell I and Cell II in order to characterize the dynamical properties of these asteroids more accurately. The results of dynamical modelling show that some asteroids may have migrated to their current location from the Vesta family within ~2 Gy. There are objects, however, whose origin in another parent body may also be plausible. This may support the hypothesis that the number of differentiated basaltic objects in the inner and middle Main Belt should be much higher than previously assumed. We will present preliminary results for the first ~10 asteroids in Cell I and Cell II.</p>

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.

Onboard Real-time Estimation of Mean Orbital Elements with Atmospheric Drag

2013 ◽  
Vol 39 (10) ◽  
pp. 1722
Author(s):  
Zhao-Wei SUN ◽  
Wei-Chao ZHONG ◽  
Shi-Jie ZHANG ◽  
Jian ZHANG
Keyword(s):  
Real Time ◽  
Time Estimation ◽  
Atmospheric Drag ◽  
Orbital Elements ◽  
Real Time Estimation

scholarly journals Extended analytical formulae for the perturbed Keplerian motion under low-thrust acceleration and orbital perturbations

2021 ◽  
Vol 133 (3) ◽  
Author(s):  
Marilena Di Carlo ◽  
Simão da Graça Marto ◽  
Massimiliano Vasile
Keyword(s):  
Gravitational Perturbation ◽  
Low Thrust ◽  
Orbital Elements ◽  
Third Body ◽  
The Third ◽  
Orbital Perturbations ◽  
Analytical Formulae ◽  
Numerical Orbit ◽  
Body Potential

AbstractThis paper presents a collection of analytical formulae that can be used in the long-term propagation of the motion of a spacecraft subject to low-thrust acceleration and orbital perturbations. The paper considers accelerations due to: a low-thrust profile following an inverse square law, gravity perturbations due to the central body gravity field and the third-body gravitational perturbation. The analytical formulae are expressed in terms of non-singular equinoctial elements. The formulae for the third-body gravitational perturbation have been obtained starting from equations for the third-body potential already available in the literature. However, the final analytical formulae for the variation of the equinoctial orbital elements are a novel derivation. The results are validated, for different orbital regimes, using high-precision numerical orbit propagators.

Sign in / Sign up

Export Citation Format

Share Document