أوروبا 52 (كويكب)

For the moon of Jupiter, see Europa (moon). For other uses, see Europa (disambiguation).
52 Europa
52 Europa VLT (2021), deconvolved.pdf
الاكتشاف
اكتشفههـ. گولدشميت
تاريخ الاكتشاف4 February 1858
التسميات
تعيين الكوكب الأصغر(52) Europa
النطق /jʊˈroʊpə/[1]
مسمى على اسم
أوروپا
1948 LA
Main belt
الصفاتEuropan, Europian
السمات المدارية[2]
حقبة July 01, 2021
(JD 2459396.5, heliocentric)
Aphelion3.444 AU (510 Gm)
Perihelion2.75 AU (420 Gm)
3.095 AU (460 Gm)
Eccentricity0.111
5.45 yr (1989 d)
21°
Inclination7.48°
129°
343°
السمات الطبيعية
الأبعادc/a = 0.67±0.04[3]
(379±16)×(330±8)×(249±10) km[4]
Mass(24±4)×1018 kg[3]
(22.6±1.6)×1018 kg[أ][5]
Mean density
1.41±0.23 g/cm3[3]
1.5±0.4 g/cm3[4]
5.63 h[2]
0.057±0.007 geometric (0.679±0.017 BV, 0.338±0.028 UB)[2]
Temperature~173 K
max: 258K (−15 °C)[6]
C/CF[2]
6.48[2]

أوروبا 52 52 Europa كويكب سماوي يقع في حزام الكويكبات الواقع بين مدارى المريخ والمشتري . اكتشفه هرمان گولدشميت في 4 فبراير 1858ـ من بلكونته في باريس. ويبلغ قطره نحو 292 كيلو متر. . وهو مسمى على اسم أوروپا، احدى غنائم زيوس في الأساطير اليونانية، وهو الاسم الذي تتقاسمه مع قمر المشتري الذي يحمل نفس الاسم.

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السمات الطبيعية

3D model of Europa based on lightcurve modeling

Europa is approximately the sixth largest asteroid by volume. Most likely it has a density of around 1.5 g/cm3, typical of C-type asteroids.[4] In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of (1.9±0.4)×1019 kg.[7] A more recent estimate by Baer suggests it has a mass of 3.27×1019 kg.[8]

Europa is a very dark carbonaceous C-type, and is the second largest of this group. Spectroscopic studies have found evidence of olivines and pyroxenes on the surface,[9] and there is some indication that there may be compositional differences between different regions[10] It orbits close to the Hygiea asteroid family, but is not a member.

Lightcurve data for Europa have been particularly tricky to interpret, so much so that for a long time its period of rotation was in dispute (ranging from 5+1⁄2 hours to 11 hours), despite numerous observations.[11] It has now been determined that Europa is a prograde rotator, but the exact direction in which its pole points remains ambiguous. The most detailed analysis indicates that it points either towards about ecliptic coordinates (β, λ) = (70°, 55°) or (40°, 255°) with a 10° uncertainty.[12] This gives an axial tilt of about 14° or 54°, respectively.

In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.[13]


أرصاد

It has been found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.[14]

Animation of 52 Europa's orbit 2000–2020
   Sun   Earth •    Mars •   Jupiter •    52 Europa

ملاحظات

  1. ^ (11.39 ± 0.79) × 10−12 M☉

المراجع

Michalak, G. (2001). "Determination of asteroid masses". Astronomy & Astrophysics. 374: 703–711. doi:10.1051/0004-6361:20010731. Retrieved 2008-11-15.</ref> In 2007, Baer and Chesley estimated Europa to have a mass of (1.9±0.4)×1019 kg.[7] A more recent estimate by Baer suggests it has a mass of 1.65×1019 kg.<ref name=Baer>Baer, James (2008). "Recent Asteroid Mass Determinations". Personal Website. Retrieved 2008-11-29.

أنظر أيضا

المصادر

  2. Michałowski, T., et al. Photometry and models of selected main belt asteroids I. 52 Europa, 115 Thyra, and 382 Dodona, Astronomy & Astrophysics, Vol. 416, p. 353 (2004).
  3. PDS lightcurve data
  4. Dotto, E., et al. ISO results on bright Main Belt asteroids: PHT–S observations, Astronomy & Astrophysics, Vol. 358, p. 1133 (2000).
  5. Sawyer, S. R., A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids, PhD thesis, The University of Texas (1991).
  6. Schmeer, P., and M. L. Hazen, CV Aquarii identified with (52) Europa, Journal of the American Association of Variable Star Observers, Vol. 28, p. 103 (2000).
  7. Zappalà, V.; M. di Martino and S. Cacciatori On the ambiguity of rotational periods of asteroids - The peculiar case of 52 Europa, Icarus, Vol. 56, p. 319 (1983).

وصلات خارجية

  1. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ^ أ ب ت ث ج JPL data Retrieved 2021-09-29
  3. ^ أ ب ت ث P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
  4. ^ أ ب ت ث خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Merline
  5. ^ James Baer, Steven Chesley & Robert Matson (2011) "Astrometric masses of 26 asteroids and observations on asteroid porosity." The Astronomical Journal, Volume 141, Number 5
  6. ^ Dotto, E.; Müller, T. G.; Barucci, M. A.; Encrenaz, Th.; Knacke, R. F.; Lellouch, E.; Doressoundiram, A.; Crovisier, J.; Brucato, J. R.; Colangeli, L.; Mennella, V. (2000). "ISO results on bright Main Belt asteroids: PHT-S observations". Astronomy and Astrophysics. 358: 1134. Bibcode:2000A&A...358.1133D. Retrieved 23 February 2024.
  7. ^ أ ب Baer, James; Steven R. Chesley (2007). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris". Celestial Mechanics and Dynamical Astronomy. Springer Science+Business Media B.V. 2007. 100 (2008): 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8. خطأ استشهاد: وسم <ref> غير صالح؛ الاسم "Baer2007" معرف أكثر من مرة بمحتويات مختلفة.
  8. ^ Baer, James (2008). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 29 November 2008.
  9. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Dotto00
  10. ^ Sawyer, Scott Raleigh (1 January 1991). "A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids". PhD Thesis. Bibcode:1991PhDT.......105S – via NASA ADS.
  11. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Zappala83
  12. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Michalowski04
  13. ^ Gradie, J.; Flynn, L. (March 1988), A Search for Satellites and Dust Belts Around Asteroids: Negative Results, 19, pp. 405–406, Bibcode: 1988LPI....19..405G. 
  14. ^ "CV Aquarii identified with (52) Europa" (PDF). Archived from the original (PDF) on 14 February 2006. Retrieved 29 April 2006.
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