52 Europa
{{Short description|Large asteroid in the asteroid belt}}
{{for-multi|the moon of Jupiter|Europa (moon)|other uses|Europa (disambiguation)}}
{{Use dmy dates|date=January 2020}}
{{Infobox planet
| minorplanet=yes
| background=#D6D6D6
| name=52 Europa
| symbol =
| image = 52 Europa VLT (2021), deconvolved.pdf
| image_size =
| caption =
| discoverer=H. Goldschmidt
| discovered=4 February 1858
| mpc_name=(52) Europa
| alt_names=1948 LA
| pronounced ={{IPAc-en|j|ʊ|ˈ|r|oʊ|p|ə}}Noah Webster (1884) A Practical Dictionary of the English Language
| adjective = Europan, Europian
| named_after = Europa
| mp_category=Main belt
| orbit_ref = [https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Europa JPL data] Retrieved 2021-09-29
| epoch=July 01, 2021
(JD 2459396.5, heliocentric)
| semimajor=3.095 AU (460 Gm)
| perihelion=2.75 AU (420 Gm)
| aphelion=3.444 AU (510 Gm)
| eccentricity=0.111
| period=5.45 yr (1989 d)
| inclination=7.48°
| asc_node=129°
| arg_peri=343°
| mean_anomaly=21°
| dimensions = (379±16)×(330±8)×(249±10) km
| flattening = 0.33{{efn|1=Flattening derived from the maximum aspect ratio (c/a): , where (c/a) = {{val|.67|.04}}.}}
| mean_diameter={{val|319|4|u=km}}P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
{{val|315|7|u=km}}
| mass={{val|24|4|e=18|u=kg}}
{{val|22.6|1.6|e=18|u=kg}}{{refn|group=lower-alpha|(11.39 ± 0.79) × 10−12 {{Solar mass}}}}James Baer, Steven Chesley & Robert Matson (2011) "Astrometric masses of 26 asteroids and observations on asteroid porosity." The Astronomical Journal, Volume 141, Number 5
| density={{val|1.41|.23|u=g/cm3}}
{{val|1.5|0.4|u=g/cm3}}
| albedo={{val|0.057|.007}} geometric ({{val|0.679|0.017}} BV, {{val|0.338|0.028}} UB)
| single_temperature=~173 K
max: 258K (−15 °C){{cite journal |last1=Dotto |first1=E. |last2=Müller |first2=T. G. |last3=Barucci |first3=M. A. |last4=Encrenaz |first4=Th. |last5=Knacke |first5=R. F. |last6=Lellouch |first6=E. |last7=Doressoundiram |first7=A. |last8=Crovisier |first8=J. |last9=Brucato |first9=J. R. |last10=Colangeli |first10=L. |last11=Mennella |first11=V. |author-link3=Maria A. Barucci|author-link4=Thérèse Encrenaz|author-link7=Alain Doressoundiram|author-link8=Crovisier|title=ISO results on bright Main Belt asteroids: PHT-S observations |journal=Astronomy and Astrophysics |date=2000 |volume=358 |page=1134 |url=https://ui.adsabs.harvard.edu/abs/2000A%26A...358.1133D/abstract |bibcode=2000A&A...358.1133D|access-date=23 February 2024}}
}}
52 Europa is the sixth largest asteroid in the asteroid belt, having a diameter of over 300 km, though it is not correspondingly massive. It is not round but is shaped like an ellipsoid of approximately 380×330×250 km.{{Cite journal|last=Merline|first=W.J.|author-link=W.J. Merline|date=2013|title=The Resolved Asteroid Program – Size, shape, and pole of (52) Europa|journal=Icarus|volume=225|issue=1|pages=794–805|arxiv=1301.5101|bibcode=2013Icar..225..794M|doi=10.1016/j.icarus.2013.01.010|s2cid=119286695}} It was discovered on 4 February 1858, by Hermann Goldschmidt from his balcony in Paris. It is named after Europa, one of Zeus's conquests in Greek mythology, a name it shares with Jupiter's moon Europa.
Physical characteristics
file: 52 Europa Lightcurve Inversion.png 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. In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of {{val|1.9|0.4|e=19}} kg.{{cite journal
|first=James |last=Baer |author-link=James Baer
|author2=Steven R. Chesley
|author2-link=Steven R. Chesley
|title=Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris
|journal=Celestial Mechanics and Dynamical Astronomy
|volume=100 |issue=2008 |pages=27–42
|publisher=Springer Science+Business Media B.V. 2007
|doi=10.1007/s10569-007-9103-8
|date=2007 |bibcode = 2008CeMDA.100...27B |doi-access=free}} A more recent estimate by Baer suggests it has a mass of 3.27{{e|19}} kg.
{{cite web
|date=2008
|title=Recent Asteroid Mass Determinations
|publisher=Personal Website
|first=James
|last=Baer
|url=http://home.earthlink.net/~jimbaer1/astmass.txt
|access-date=29 November 2008
|archive-url=https://web.archive.org/web/20130702212735/http://home.earthlink.net/~jimbaer1/astmass.txt
|archive-date=2 July 2013
|url-status=dead
}}
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, and there is some indication that there may be compositional differences between different regions.{{cite journal|title=A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids.|first=Scott Raleigh|last=Sawyer|date=1 January 1991|journal=PhD Thesis|via=NASA ADS|bibcode=1991PhDT.......105S}} 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 {{frac|5|1|2}} hours to 11 hours), despite numerous observations. 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. 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.{{Citation
| last1 = Gradie
| first1 = J.
| last2 = Flynn
| first2 = L.
| title = A Search for Satellites and Dust Belts Around Asteroids: Negative Results
| work = Abstracts of the Lunar and Planetary Science Conference
| volume = 19
| pages = 405–406
|date=March 1988
| bibcode = 1988LPI....19..405G
| postscript= .
}}
Observations
It has been found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.{{cite web|url=http://www.aavso.org/publications/ejaavso/v28n2/103.pdf |title=CV Aquarii identified with (52) Europa|access-date=29 April 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060214091638/http://www.aavso.org/publications/ejaavso/v28n2/103.pdf |archive-date=14 February 2006 }}
File:Animation of 52 Europa orbit 2000-2020.gif
{{clear}}
Notes
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References
{{reflist|refs=
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Bibliography
- [https://archive.today/20060614093519/http://www.psi.edu/pds/archive/lc.html PDS lightcurve data]
- {{cite thesis |last1=Sawyer |first1=S. R. |title=A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids PhD thesis |publisher=The University of Texas |year=1991|bibcode=1991PhDT.......105S }}
- Schmeer, P., and M. L. Hazen, [https://web.archive.org/web/20060214091638/http://www.aavso.org/publications/ejaavso/v28n2/103.pdf CV Aquarii identified with (52) Europa], Journal of the American Association of Variable Star Observers, Vol. 28, p. 103 (2000).
External links
- {{cite web | title=Elements and Ephemeris for (52) Europa | url=http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=b2011&o=00052 | access-date=26 May 2011 | url-status=dead | archive-url=https://web.archive.org/web/20160304051741/http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=b2011&o=00052 | archive-date=4 March 2016 }}
- [http://www.rni.helsinki.fi/~mjk/Micha.pdf shape model deduced from lightcurve]
- {{AstDys|52}}
- {{JPL small body}}
{{Minor planets navigator |51 Nemausa |number=52 |53 Kalypso}}
{{Large asteroids}}
{{Authority control}}
{{DEFAULTSORT:000052}}
Category:CF-type asteroids (Tholen)