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21795 Masi (1999 SN9)
Classification: Main-belt Asteroid          SPK-ID: 2021795
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 19 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1923607413410238 3.1615e-08  
a 2.381664369266257 8.85e-09 au
q 1.923525645568698 7.4766e-08 au
i 1.837637390442552 4.2578e-06 deg
node 337.0690369107207 0.00011511 deg
peri 81.60560060090137 0.00011575 deg
M 192.0427168554393 1.4132e-05 deg
tp 2459626.847871990287
(2022-Feb-16.34787199)
5.488e-05 TDB
period 1342.515368758545
3.68
7.4829e-06
2.049e-08
d
yr
n .2681533547976441 1.4946e-09 deg/d
Q 2.839803092963816 1.0552e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1379  
   data-arc span      24562 days (67.25 yr)  
   first obs. used      1953-04-15  
   last obs. used      2020-07-14  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .50979  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Nov-13 01:54:56  

Additional Information
 Earth MOID = .936877 au 
 Jupiter MOID = 2.50142 au 
 T_jup = 3.512 
[ hide covariance matrix ]
Orbital Elements at Epoch 2457070.5 (2015-Feb-17.0) TDB
Reference: JPL 19 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1918861038542287 3.1716e-08  
q 1.924904611884665 7.4965e-08 au
tp 2456943.164190845339
(2014-Oct-12.66419085)
4.7005e-05 TDB
node 337.1165932698309 0.00011501 deg
peri 81.85161688884263 0.00011565 deg
i 1.838991376535134 4.2581e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      1379  
   data-arc span      24562 days (67.25 yr)  
   first obs. used      1953-04-15  
   last obs. used      2020-07-14  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .50979  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Nov-13 01:54:56  

Additional Information
 Jupiter MOID = 2.50142 au 
 T_jup = 3.512 
Orbit Covariance (6×6)
  e q tp node peri i
e 1.005935464274372E-15 -2.367072418284915E-15 2.171468572842355E-13 -1.053849138818854E-15 6.339027772438423E-14 6.656238089722758E-18
q -2.367072418284915E-15 5.619825013045722E-15 -3.836715337185785E-13 2.536329888785979E-15 -1.156779666280437E-13 1.730345617969428E-17
tp 2.171468572842355E-13 -3.836715337185785E-13 2.209444570347401E-9 3.457970106167329E-12 5.842400004342266E-10 -2.342762812423125E-13
node -1.053849138818854E-15 2.536329888785979E-15 3.457970106167329E-12 1.322760920365112E-8 -1.321949124347515E-8 -7.046795207989436E-11
peri 6.339027772438423E-14 -1.156779666280437E-13 5.842400004342266E-10 -1.321949124347515E-8 1.337577070377888E-8 7.037297288462303E-11
i 6.656238089722758E-18 1.730345617969428E-17 -2.342762812423125E-13 -7.046795207989436E-11 7.037297288462303E-11 1.813176289051843E-11

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 14.9   n/a MPO337442  
diameter diameter 3.150 km 0.164 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
rotation period rot_per 13.862 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so.
Published Reference List:
[Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.]
geometric albedo albedo 0.235   0.037 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

21795 Masi           Discovered 1999 Sept. 29 by F. Mallia at Campo Catino.
Gianluca Masi (b. 1972), an amateur astronomer since 1980, is involved with several scientific projects, mainly on cataclysmic variable stars and minor planets. He has discovered a variable star and several minor planets. He collaborates with several institutions through several observing programs.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20010509/MPCPages.arcLast Updated: 2009-05-11

[ show close-approach data ]
Alternate Designations
 1999 SN9 = 1988 UE = 1993 BZ1 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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