Determination of the Yarkovsky Effect Parameter for Asteroids with Small Perihelion Distances

Author(s):  
O. M. Syusina ◽  
T. Yu. Galushina
Author(s):  
T.Yu. Galushina ◽  
◽  
O.N. Letner ◽  
O.M. Syusina ◽  
◽  
...  

The paper presents the results of assessment definition precision of the Yarkovsky effect parameter A 2 for asteroids with small perihelion distances, known on epoch January 2021. It is shown that the observation interval has a significant effect on the precision of A 2. As the interval increases, the root mean square error of the parameter decreases. For asteroids (3200) Phaethon and (137924) 2000 BD19 with a large observation interval, an experiment was carried out to reduce the number of real observations. A decrease of the interval and number of observations leads to a loss in the precision of the parameter being determined. Modeling observations based on real ones with an increase in their precision showed that the root mean square error of the A 2 parameter decreases in proportion to the increase in the observation precision. The increase of interval due to model observations confirmed the conclusion about the inverse dependence of the A 2 uncertainty from number and interval of observations.


Author(s):  
O. M. Syusina ◽  
◽  
T. Yu. Galushina ◽  

The paper presents investigation of influence the sample of observations on the determination of the Yarkovsky effect parameter for some asteroids with small perihelion distances. It is shown that when excluding observations that do not exceed the precision of ”3 sigma”, the value of this effect changes within the obtained precision.


Author(s):  
O.M. Syusina ◽  
◽  
T.Yu. Galushina ◽  

Presents the results of determining the parameter of the Yarkovsky effect for all asteroids with small perihelion distances known for January 2021. The comparison of the obtained values is carried out with the results obtained earlier, based on a different approach and with the results presented on the NASA website. On the example of a number of objects, influence of observations of different accuracy influence on the obtained value of the parameter of the Yarkovsky effect was investigated.


2021 ◽  
Author(s):  
Rodrigo Leiva ◽  
Paolo Tanga ◽  
Luana Liberato

<p>A new 50 cm telescope, the UniversCity telescope, was recently installed at Plateau de Calern, France, to survey stellar occultation by asteroids from collisional families. A stellar occultation occurs when an asteroid passes in front of a distant star blocking its light temporarily. Measuring the time of the occultations provides an accurate astrometric measurement of the asteroid, comparable with the angular size of the asteroid. Thanks to the astrometric catalog from the Gaia mission, astrometry accuracy from occultation reaches a few milliarcseconds.</p><p>The astrometry from the survey is used in turn to improve the orbit of the asteroid, while the duration of the occultation is used to constrain physical characteristics and search for binarity. The orbit improvement aims to detect and measure the drift rate in the orbital elements of asteroids due to the Yarkovsky effect, a non-gravitational force responsible for scattering the orbital elements of collisional family members. Combining the magnitude of the Yarkovsky drift rate from the occultation survey with the accumulated drift since the originating collision, the age determination of the collisional family can be obtained.</p><p>The occultation survey takes advantage of the stellar occultation technique and the Gaia astrometric catalog to systematically derive accurate astrometric measurements for collisional family members.</p><p>The telescope will be operated robotically, dedicating most of its time to the occultation survey, with a small percentage of time to other science cases. The large number of family members and candidates to stellar occultations demands the automation of the occultation prediction, the selection and prioritization of occultation events, telescope scheduling, data reduction, and data analysis.</p><p>The occultation predictions are updated regularly in the light of new astrometric measurements from traditional astrometry and from occultations measurements. The occultations predicted to be visible from the UniversCity site are prioritized based on their chances of detection and contribution to the family age determination. The data acquired each night is automatically reduced to obtain light curves from which detection candidates are analyzed.</p><p>We will present the status of the project and the development and performances of the automatic prediction and processing system.</p>


1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.


1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.


1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).


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