Перейти в головне навігаційне меню Перейти до головного Перейти на нижній колонтитул сайту
Логотип заголовку сторінки

Фізико-математичні науки

February 14, 2025; Boston, USA: VII Міжнародна науково-практична конференція «SCIENTIFIC PRACTICE: MODERN AND CLASSICAL RESEARCH METHODS»


PLUTO'S SATELLITE HYDRA


DOI
https://doi.org/10.36074/logos-14.02.2025.047
Опубліковано
15.03.2025

Анотація

The "New Horizons" team suspected that Pluto and Charon might have other small moons and rings around them. Remote sensing data from the Hubble Space Telescope were used to test this hypothesis. In May 2005, this led to the discovery of the Nix and Hydra satellites. It is believed that all of Pluto's smaller moons were formed from debris ejected from a powerful collision between Pluto and another Kuiper Belt object. The debris from this collision eventually coalesced into Pluto and all of its moons. Due to tidal interactions, Hydra's orbit around the Pluto-Charon barycenter gradually became more circular over time. Images from the "New Horizons" spacecraft in July 2015 with detailed images of the satellite Hydra, for the first time allowed us to determine the dimensions of this satellite quite accurately: 50.9 km × 36.1 km × 30.9 km. Hydra turned out to be the second largest satellite of Pluto. In terms of distance, Hydra is the fifth and most distant satellite of Pluto with a semi-major axis of its orbit of 64738 km. Its mass is (3.01±0.30)×1016 kg, with an average density of 1.220±0.150 g/cm3. The synodic period of rotation around the axis is 10.31h. The average temperature of its surface is close to 23 K. In general, the surface of Hydra turned out to be very bright with a high degree of reflection, although with significant variations in brightness. On average, it reflects almost 83% of the sunlight falling on it. This means that Hydra's surface should be covered with water ice. Like other small satellites of Pluto, Hydra's surface has a neutral spectrum. And the water ice on the surface of Hydra is quite clean and therefore does not show significant darkening. One explanation for this state is that Hydra's surface is frequently updated by micrometeorite impacts, which eject lighter material from beneath the surface of the satellite. According to crater counting data from observations by the "New Horizons" space probe, the age of Hydra's surface is estimated at about four billion years. Studies of Hydra show that it rotates chaotically. Its rotation period and axial tilt vary to the point that its axis of rotation regularly flips. The chaotic nature of Hydra's motion is largely due to the different gravitational influences of Pluto and Charon. The chaotic nature of the satellite's motion is also enhanced by its rather irregular shape. During the "New Horizons" flyby of Pluto and its moons, Hydra had a rotation period of about 10 hours; its axis of rotation was tilted nearly 110 degrees to the plane of its orbit. Like all Pluto's moons, Hydra's orbit is nearly circular and coplanar with Charon's orbit. Hydra is in a 2:3 orbital resonance with Nix, a 6:11 resonance with Styx, and a 1:6 resonance with Charon. These resonances are maintained by periodic local fluctuations in the Pluto-Charon gravitational field strength of about 5%.

Посилання

  1. Morozhenko A.V., Vid’machenko A.P. (2004) Polarimetry and Physics of Solar System Bodies Photopolarimetry in Remote Sensing: Proceedings of the NATO Advanced Study Institute. Yalta, Ukraine. 20 September - 4 October 2003. -503 p. P. 369-384.
  2. Quillen A.C., Nichols-Fleming F., Chen Y.-Y. Noyelles B. (2017) Obliquity evolution of the minor satellites of Pluto and Charon. Icarus. 293, p. 94-113.
  3. Showalter M.R., Hamilton D.P. (2015) Resonant interactions and chaotic rotation of Pluto's small moons. Nature. 522(7554), p. 45-49.
  4. Steffl A., Weaver H.A., Stern S.A., et al. (2006) New Constraints on Additional Satellites of the Pluto System. The Astronomical Journal. 132(2), p. 614-619.
  5. Steklov A.F., Vidmachenko A.P., Miniailo N.F. (1983) Seasonal variations in the atmosphere of Saturn. Soviet Astronomy Letters 9 (Mar.-Apr. 1983), p. 135, 136.
  6. Stern S.A., Bagenal F., Ennico K., et al. (2015) The Pluto system: Initial results from its exploration by New Horizons. Science, 350 (6258), id.aad1815.
  7. Stern S.A., 25 Weaver H.A., Steff A.J., et al. (2006). A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper belt. Nature. 439(7079), p. 946-948.
  8. Quillen A.C., Nichols-Fleming F., Chen Y.-Y., Noyelles B. (2017) Obliquity evolution of the minor satellites of Pluto and Charon. Icarus. 293, p. 94-113.
  9. Verbiscer A.J., Porter S.B., Buratti B.J., et al. (2018) Phase Curves of Nix and Hydra from the New Horizons Imaging Cameras. The Astrophysical Journal. 852(2), p. L35-1-L35-4.
  10. Vid’Machenko A.P. (1991) Giant planets – Theoretical and observational aspects. Astronomicheskii Vestnik. May-June 1991, 25(3), p. 277-292.
  11. Vid’Machenko A.P. (1997) Temporal changes in methane absorption in Jupiter’s atmosphere. Kinematics and Physics of Celestial Bodies. 13(6), p. 21-25.
  12. Vidmachenko A.P. (1985) Reflectivity of Saturn's south equatorial region from 1977 through 1981. Solar System Research. 18(3), p. 123-128.
  13. Vidmachenko A.P. (2000) Variations of the reflective characteristics of Jupiter’s atmosphere. 31st Lunar and Planetary Science Conference. March 13-17, 2000, Houston, Texas, abstract no. 1060.
  14. Vidmachenko A.P. (2005) Sedna: the history of the discovery and its features. Astronomical almanac, 52, p. 201-212.
  15. Vidmachenko A.P. (2015) Dwarf planets (to the 10th anniversary of the introduction of the new class of planets). Astronomical almanac, 62, p. 228-249.
  16. Vidmachenko A.P. (2015) Influence of solar activity on seasonal variations of methane absorption in the atmosphere of Saturn. Kinematics and Physics of Celestial Bodies. 31(3), p. 131-140.
  17. Vidmachenko A.P. (2016) Features of surface topography and the geological activity of Pluto. 18 International scientific conference Astronomical School of Young Scientists. National Aviation University, Kyiv, Ukraine, May, 26-27, 2016. P. 12-14.
  18. Vidmachenko A.P. (2016) Seasonal changes on Jupiter. I. Factor of activity of hemispheres. Kinematics and Physics of Celestial Bodies, 32(4), p. 189-195.
  19. Vidmachenko A.P. (2016) The floating ices on the surface of Pluto. 18 International scientific conference Astronomical School of Young Scientists. National Aviation University, Kyiv, Ukraine, May 26-27 2016, p. 10-12.
  20. Vidmachenko A.P. (2018) Modern volcanic activity on the Moon. 20 International scientific conference Astronomical School of Young Scientists. May 23-24, 2018. Uman, Ukraine. P. 5-7.
  21. Vidmachenko A.P. (2019) Pluto (to the 90th anniversary of the discovery of the planet). Astronomical almanac, 66, p. 217-229.
  22. Vidmachenko A.P. (2022) Features of seasonal changes on Pluto. Proceedings of the 8th International scientific and practical conference. Science, innovations and education: problems and prospects. (March 9-11, 2022). Chapter 17. CPN Publishing Group. Tokyo, Japan. P. 108-116.
  23. Vidmachenko A.P. (2024) About discovering and getting of all new information about the now dwarf planet Pluto. Proceedings of the XIII International Scientific and Prhctical Conference «Modern science: fundamental and applied aspects», December 30-31, 2024, Beijing. China. P. 20-26.
  24. Vidmachenko A.P. (2025) Features of Pluto’s rotation around its axis and around the Sun. Sciences of Europe. Editorial office: Křižíkova 384/101 Karlín, 18600 Praha. 156,
  25. p. 24-28.
  26. Vidmachenko A.P. (2025) The earliest data on the general characteristics of Pluto's topography. Proceedings of the 5th International scientific and practical conference “Science in the modern world: innovations and challenges”. (January 23-25, 2025). Chapter 35. Perfect Publishing. Toronto, Canada. 624 p. P. 202-211.
  27. Vidmachenko A.P., Dlugach Z.M., Morozhenko O.V. (1984) Nature of the optical nonuniformity in Saturn's disk. Solar System Research 17(4), p. 164-171.
  28. Vidmachenko A.P., Morozhenko O.V. (2017) Physical characteristics of the surface of satellites and rings of giant planets. Kyiv. Editorial and publishing department of NUBiP of Ukraine. -412 p.
  29. Vidmachenko A.P., Vidmachenko H.A. (2007) Is it dangerous asteroids? Astronomical almanac, 53, p. 195-207.
  30. Ward W.R., Canup R.M. (2006) Forced Resonant Migration of Pluto's Outer Satellites by Charon. Science. 313(5790), p. 1107-1109.
  31. Weaver H.A., Buie M.W., Showalter M.R., et al. (2016) The Small Satellites of Pluto as Observed by New Horizons. Science. 351(6279): aae0030-1-26.

Статті цього автора (авторів), які найбільше читають