The observation of stars occultation by asteroid (259) Alethea and comet 21p/Jacobini-Zinner

Heading: 
Dynamics and Physics of Solar System Bodies
Kleshchonok, VV, 1Karbovsky, VL, 2Buromsky, MI, 1Lashko, MV
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
2Astronomical Observatory of Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2021, 37(1):71-88
https://doi.org/10.15407/kfnt2021.01.071
Start Page: Dynamics and Physics of Bodies of the Solar System
Language: Ukrainian
Abstract: 

The description and parameters of the complex for observing of occultations of stars by Solar system bodies are given. The results of the study of two phenomena which obtained using this complex are described. The jet with sharp boundaries with an optical thickness of 0.035 ± 0.012 and an angle of ejection in 54.6° was detected, when the occultation of star HD 45314 by the comet 21P/Jacobini-Zinner was observed. The single-scattering albedo of the dust particles of this jet lies in the range from 0.04 to 0.06, The 185 km asteroid chord was registered, when occultation of the star UCAC4-475-051755 by asteroid (259) Alethea was observed. Justifications are given that the asteroid of Alethea has an ellipsoidal shape with an axis ratio of 1:1.19. The description and parameters of the complex for observing occultations of stars by Solar system bodies are given. The complex is designed for observations with the AZT-2 telescope (D = 700 mm, F = 10500 mm) of the МAO NAS of Ukraine with an optical focal length reducer, but can also be mounted on other telescopes. The complex uses an Apogee Alta U47 CCD camera as a light detector, which operates in the drift scan mode. The results of the study of two phenomena which obtained using this complex are described. During the observations on September 21, 2018, the phenomenon of a decrease in the brightness of the star HD 45314 near the ephemeris moment of occultation by comet 21P / Giacobini-Zinner by about 0.04m was recorded. This value exceeds the possible level of errors in the photometry of the star track. A possible explanation of this effect by attenuation of light in a comet’s symmetrical dust coma is analyzed. It is shown that in this way the magnitude of the attenuation of light cannot be explained. The resulting decrease in brightness is explained by the passage of a star through a jet structure with sharp boundaries with an optical thickness of 0.035 ± 0.012 and an opening angle of 54.6°. The single-scattering albedo of the dust particles of this jet lies in the range from 0.04 to 0.06. The occultation of the star UCAC4-475-051755 by asteroid (259) Alethea was recorded with duration of 16.7 s on March 31, 2019. This occultation duration corresponds to an asteroid chord of 185 km with the expected one 61 km, which exceeds the accepted value of the asteroid diameter of 179 km. This difference is explained by the fact that the asteroid (259) Alethea has an ellipsoidal shape. Justifications are given that the ratio of the axes of an ellipsoid for an asteroid is 1 : 1.19.

Keywords: asteroid (259) Alethea, comet 21P / Jacobini-Zinner, occultations

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References: 

1. Karbovsky V., Kleshchonok V., Buromsky M. (2017) Software and hardware complex for observation of star occultations by asteroids. Bull. Nat. Taras Shevchenko Univ. Kyiv. Astron. 2(56). 41— 44.
https://doi.org/10.17721/BTSNUA.2017.56.41-44

2. Andrae R., Fouesneau M., Creevey O., Ordenovic Ch., Mary N., Burlacu A., Chaoul L., Jean-Antoine-Piccolo A., Kordopatis G., Korn A., Lebreton Y., Panem Ch., PichonB., ThJvenin F., Walmsley G., Bailer-Jones C. A. L. (2018) Gaia Data Release 2. First stellar parameters from Apsis. Astron. and Astrophys. 61(A8).29.
https://doi.org/10.1051/0004-6361/201732516

3. Braga-Ribas F., Sicardy B., Ortiz J. L., et al. (2014) A ring system detected around the Centaur (10199) Chariklo. Nature. 508(7494). 72—75.
https://doi.org/10.1038/nature13155

4. Carry B. (2012) Density of asteroids. Planetary and Space Sci. 73(1).98—118.
https://doi.org/10.1016/j.pss.2012.03.009

5. Chornaya E., Zubko E., Luk’yanyk I., Kochergin A., Zheltobryukhov M., Ivanova O., Kornienko G., Matkin A., Baransky A., Molotov I., Sharoshchenko V., Videen G. (2020) Imaging polarimetry and photometry of comet 21P/Giacobini-Zinner. Icarus. 337(113).471.
https://doi.org/10.1016/j.icarus.2019.113471

6. Clairemidi J., Moreels G., Krasnopolsky V. A. (1990) Gaseous CN, C2, and C3 jets in the inner coma of Comet P/Halley observed from the Vega 2 spacecraft. Icarus. 86, 115—128.
https://doi.org/10.1016/0019-1035(90)90203-L

7. Elliot J. L., Dunham E., Mink D. (1977) The rings of Uranus. Nature. 267(5609). 328— 330.
https://doi.org/10.1038/267328a0

8. Fern<ndez Y. R., Wellnitz D. D., Buie M. W., et al. (1999) The inner coma and nucleus ofcometHale-Bopp: Results from a stellar occultation. Icarus. 140(1). 205—220.
https://doi.org/10.1006/icar.1999.6127

9. Kolokolova L., Hanner M. S., Levasseur-Regourd A.-C., Gustafson B. E. S. (2005) Physi­cal properties of cometary dust from light scattering and thermal emission. Comets II, Eds M. Festou, H. U. Keller, H. A. Weaver (Tucson, AZ: Univ. of Arizona Press). 577—604.

10. Larson S. M., A’Hearn M. F. (1984) Comet Bowell (1980b) — Measurement of the optical thickness of the coma and particle albedo from a stellar occultation. Icarus. 58. 446—450.
https://doi.org/10.1016/0019-1035(84)90090-3

11. Larson S. M., Sekanina Z. (1984) Coma morphology and dust-emission pattern of periodic Comet Halley. I-High-resolution images taken at Mount Wilson in 1910. Astron. J. 89. 571—578.
https://doi.org/10.1086/113551

12. Lawler M. E., Brownlee D. E. (1992) CHON as a component of dust from comet Halley. Nature. 359. 810—812.
https://doi.org/10.1038/359810a0

13. Lebofsky L. A., Spencer J. R. (1989) Radiometry and thermal modeling of asteroids. Asteroids II, ed. R. P. Binzel, Tucson: Univ. of Arizona Press. 128.

14. Marchis F., Kaasalainen M., Hom E. F. Y., Berthier J., Enriquez J., Hestroffer D., Le Mignant D., de Pater I. (2006) Shape, size and multiplicity of mainbelt asteroids. Icarus. 185. 39—63.
https://doi.org/10.1016/j.icarus.2006.06.001

15. Masiero J. R., Mainzer A. K., Grav T., Bauer J. M., Cutri R. M., Dailey J., Eisenhardt P. R. M., McMillan R. S., Spahr T. B., Skrutskie M. F., Tholen D., Walker R. G., Wright E. L., DeBaun E., Elsbury D., Gautier IV T., Gomillion S., Wilkins A. (2011) Main belt asteroids with WISE/NEOWISE. I. Preliminary albedos and diameters. Astro­phys. J. 741(68). 20.
https://doi.org/10.1088/0004-637X/741/2/68

16. Pittichova J., Woodward C. E., Kelley M. S., Reach W. T. (2008) Ground-based optical and Spitzer infrared imaging observations of comet 21P/Giacobini-Zinner. Astron. J. 136. 1127—1136.
https://doi.org/10.1088/0004-6256/136/3/1127

17. Pravec P., Harris A. W., Warner B. D. (2002) Asteroid photometry opportunities. The Minor Planet Bull. 29.19.

18. Rosenbush V. K. (2005) Opposition effects in brightness, color, and polarization of comet 1P/Halley: Comparison with atmosphereless Solar system bodies. Solar System Res. 39. 312—321.
https://doi.org/10.1007/s11208-005-0045-y

19. Ryan E. L., Usui F., Kuroda D., Muller T. G., Hasegawa S., Ishiguro M., Ootsubo T., Ishihara D., Kataza H., Takita S., Oyabu S., Ueno M., Matsuhara H., Onaka T. (2011) Asteroid catalog using AKARI: AKARI/IRC mid-infrared asteroid survey. Publs Astron. Soc. Jap. 63. 1117—1138.
https://doi.org/10.1093/pasj/63.5.1117

20. Ryan E. L., Woodward C. E. (2010) Rectified asteroid albedos and diameters from IRAS and MSX photometry catalogs. Astron. J. 140. 933—943.
https://doi.org/10.1088/0004-6256/140/4/933

21. Samus’ N. N., Kazarovets E. V., Durlevich O. V., Kireeva N. N., Pastukhova E. N. (2017) General catalogue of variable stars: Version GCVS 5.1. Astron. Repts. 61(1). 80—88.
https://doi.org/10.1134/S1063772917010085

22. Tanga P., Delbo M. (2007) Asteroid occultations today and tomorrow: toward the GAIA era. Astron. and Astrophys. 474. 1015—1022.
https://doi.org/10.1051/0004-6361:20077470

23. Tedesco E. F., Noah P. V., Noah M. C., Price S. D. (2004) IRAS Minor Planet Survey. NASA Planetary Data System. IRAS-A-FPA-3-RDR-IMPS-V6.0.

24. Zacharias N., Finch C. T., Girard T. M., Henden A., Bartlett J. L., Monet D. G., Zacharias M. I. (2013) The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4). Astron. J. 145. 44.
https://doi.org/10.1088/0004-6256/145/2/44