| 词条 | 817 Annika |
| 释义 |
| minorplanet=yes | background=#D6D6D6 | name=817 Annika | discoverer=Max Wolf | discovered=6 February 1916 | mpc_name=(817) Annika | alt_names=1916 YW | mp_category=Main belt (Eunomia family) | epoch=31 July 2016 (JD 2457600.5) | semimajor={{Convert|2.5915|AU|Gm|abbr=on}} | perihelion={{Convert|2.1292|AU|Gm|abbr=on}} | aphelion={{Convert|3.0538|AU|Gm|abbr=on|lk=on}} | eccentricity=0.17840 | period=4.17 yr (1523.8 d) | inclination=11.336° | asc_node=125.626° | arg_peri=284.728° | mean_anomaly=90.5151° | dimensions= | mean_radius={{val|11.025|0.85}} km,[1] 11 km | mass=~1.5×1016 kg (estimate) | density=~2.7 g/cm³ (estimate)[3] | rotation=0.440 d,[4] {{Convert|10.56|h|d|abbr=on|lk=on}}[1] | spectral_type=S-type asteroid | abs_magnitude=10.6 | albedo={{val|0.1740|0.030}} | mean_motion={{Deg2DMS|0.23625|sup=ms}} / day | orbit_ref=[1] | observation_arc=100.19 yr (36596 d) | uncertainty=0 }} 817 Annika is a mid-sized Eunomian asteroid. References1. ^1 2 {{Cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=817;cad=1 |title=817 Annika (1916 YW) |work=JPL Small-Body Database |publisher=NASA/Jet Propulsion Laboratory |access-date=4 May 2016}} [2][3]2. ^1 {{cite web|url=http://www.psi.edu/pds/archive/lc.html |title=PDS lightcurve data |deadurl=yes |archiveurl=https://web.archive.org/web/20060614093519/http://www.psi.edu/pds/archive/lc.html |archivedate=2006-06-14 |df= }} 3. ^1 {{cite journal |author=G. A. Krasinsky |display-authors=etal |title=Hidden Mass in the Asteroid Belt |journal=Icarus |volume=158 |page=98 |date=2002 |doi=10.1006/icar.2002.6837|bibcode = 2002Icar..158...98K }} }} External links
6 : Eunomia asteroids|Discoveries by Max Wolf|Minor planets with names of unknown origin|Named minor planets|S-type asteroids|Astronomical objects discovered in 1916 |
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