| 词条 | 990 Yerkes |
| 释义 |
| minorplanet= yes | background= #D6D6D6 | name= 990 Yerkes | mpc_name= (990) Yerkes | alt_names= 1922 MZ | discoverer= G. Van Biesbroeck | discovery_site= Williams Bay | discovered= 23 November 1922 | orbit_ref= [1] | observation_arc= 102.46 yr (37425 days) | uncertainty= 0 | epoch= 31 July 2016 (JD 2457600.5) | eccentricity= 0.21652 | semimajor= {{Convert|2.6696|AU|Gm|abbr=on}} | perihelion= {{Convert|2.0916|AU|Gm|abbr=on}} | aphelion= {{Convert|3.2477|AU|Gm|abbr=on|lk=on}} | period= 4.36 yr (1593.2 d) | inclination= 8.7872° | asc_node= 353.971° | arg_peri= 9.4832° | mean_anomaly= 216.84° | sidereal_day= {{nowrap|24.45 ± 0.05 h}} | mean_motion= {{Deg2DMS|0.22596|sup=ms}} / day | abs_magnitude= 11.7 | rotation= {{Convert|24.56|h|d|abbr=on|lk=on}} | albedo= {{val|0.1303|0.018}} | mean_radius= {{val|9.23|0.6}} km }} 990 Yerkes is a main belt asteroid discovered by Belgian-American astronomer George Van Biesbroeck in 1922, and named after the Yerkes Observatory. Photometric observations of this asteroid collected during 2009 show a rotation period of 24.45 ± 0.05 hours with a brightness variation of 0.35 ± 0.05 magnitude.References1. ^{{Cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=990;cad=1 |title=990 Yerkes (1922 MZ) |work=JPL Small-Body Database |publisher=NASA/Jet Propulsion Laboratory |access-date=2 May 2016}} }} External links
4 : Background asteroids|Discoveries by George Van Biesbroeck|Named minor planets|Astronomical objects discovered in 1922 |
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