| 词条 | 52 Europa |
| 释义 |
| minorplanet=yes | background=#D6D6D6 | name=52 Europa | image = 52 Europa Lightcurve Inversion.png | image_size = 265 | caption = 3D model of Europa based on lightcurve modeling | discoverer=H. Goldschmidt | discovered=February 4, 1858 | mpc_name=(52) Europa | alt_names=1948 LA | pronounced ={{IPAc-en|j|ʊəˈr|oʊ|p|ə}} {{Respell|yoor|OH|pə}} | named_after = Europa | mp_category=Main belt | epoch=November 26, 2005 (JD 2453700.5) | semimajor=3.101 AU (463.911 Gm) | perihelion=2.785 AU (416.621 Gm) | aphelion=3.417 AU (511.201 Gm) | eccentricity=0.102 | period=5.46 yr (1994.629 d) | inclination=7.466° | asc_node=128.992° | arg_peri=343.553° | mean_anomaly=70.730° | dimensions=(379±16)×(330±8)×(249±10) km (mean: 315±7 km)[1] 360×315×240 km[2][1] | mass=3.27{{e|19}} kg[4] | density=1.5 ± 0.4 g/cm³[1] | rotation=0.2347 d[2] | spectral_type=C-type asteroid | abs_magnitude=6.31 | albedo=0.058 | single_temperature=~173 K max: 258K (−15 °C)[3] }} Europa (minor planet designation: 52 Europa) is the 6th-largest asteroid in the asteroid belt, having an average diameter of around 315 km. It is not round but is shaped like a triaxial ellipsoid of approximately 380×330×250 km.[4] It was discovered on February 4, 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 characteristicsEuropa 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){{e|19}} kg.[5] A more recent estimate by Baer suggests it has a mass of 3.27{{e|19}} kg.[6] 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,[13] and there is some indication that there may be compositional differences between different regions[7] 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 and a half hours to 11 hours), despite numerous observations.[15] 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.[16] 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.[8] ObservationsIt has been found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.[9] References1. ^{{cite web|url=http://www.rni.helsinki.fi/~mjk/Micha.pdf|title=Helsingin yliopisto - Matematiikan ja tilastotieteen laitos|publisher=}} [10][11][12]2. ^{{cite web|url=http://www.psi.edu/pds/archive/lc.html |title=Archived copy |accessdate=2008-11-03 |deadurl=yes |archiveurl=https://archive.is/20060614093519/http://www.psi.edu/pds/archive/lc.html |archivedate=2006-06-14 |df= }} 3. ^http://aa.springer.de/papers/0358003/2301133.pdf 4. ^1 2 3 {{Cite journal|last=Merline|first=W.J.|authorlink=W.J. Merline|date=2013|title=The Resolved Asteroid Program - Size, shape, and pole of (52) Europa|journal=Icarus|volume=225|pages=794–805|arxiv=1301.5101|bibcode=2013Icar..225..794M|doi=10.1016/j.icarus.2013.01.010}} 5. ^1 {{cite journal |first=James |last=Baer |authorlink=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|url=http://www.springerlink.com/content/h747307j43863228/fulltext.pdf |format=PDF |doi=10.1007/s10569-007-9103-8 |accessdate=2008-11-15 |date=2007 |bibcode = 2008CeMDA.100...27B }} 6. ^1 {{cite web |date=2008 |title=Recent Asteroid Mass Determinations |publisher=Personal Website |first=James |last=Baer |url=http://home.earthlink.net/~jimbaer1/astmass.txt |accessdate=2008-11-29}} 7. ^{{cite journal|title=A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids.|first=Scott Raleigh|last=Sawyer|date=1 January 1991|publisher=|journal=Ph.D. Thesis|via=NASA ADS|bibcode=1991PhDT.......105S}} 8. ^{{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= .}} 9. ^{{cite web|url=http://www.aavso.org/publications/ejaavso/v28n2/103.pdf |title=Archived copy |accessdate=2006-04-29 |deadurl=yes |archiveurl=https://web.archive.org/web/20060214091638/http://www.aavso.org/publications/ejaavso/v28n2/103.pdf |archivedate=2006-02-14 |df= }} 10. ^1 {{cite journal |last1=Michałowski |first1=T |url=http://www.rni.helsinki.fi/~mjk/Micha.pdf |title=Photometry and models of selected main belt asteroids I. 52 Europa, 115 Thyra, and 382 Dodona | journal=Astronomy & Astrophysics |volume=416 |pages=353–366 |year=2004|bibcode = 2004A&A...416..353M |doi = 10.1051/0004-6361:20031706 }} 11. ^1 {{cite journal |last1=Dotto |first1=E. |url=http://aa.springer.de/papers/0358003/2301133.pdf |title=ISO results on bright Main Belt asteroids: PHT–S observations |journal=Astronomy & Astrophysics |volume=358 |page=1133 |year=2000|bibcode = 2000A&A...358.1133D }} 12. ^1 {{cite journal |last1=Zappalà |first1=V. |first2=M. |last2=di Martino |first3=S |last3=Cacciatori |title=On the ambiguity of rotational periods of asteroids: The peculiar case of 52 Europa |journal=Icarus |volume=56 |pages=319–324 |year=1983|bibcode = 1983Icar...56..319Z |doi = 10.1016/0019-1035(83)90041-6 }} }} Bibliography
External links
7 : Hygiea asteroids|Discoveries by Hermann Goldschmidt|Minor planets named from Greek mythology|Named minor planets|CF-type asteroids (Tholen)|C-type asteroids (SMASS)|Astronomical objects discovered in 1858 |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。