Hel

00949, 1921 EM, 1921EM, 1952 DN, 1952DN, 1954 SN1, 1954SN1, J21E00M, J52D00N, J54S01N

All data for this body: [vot]

MPC data
Name (number) Hel (949)
a 2.99509
e 0.20010
i / sin(i) 10.6419 / 0.18467
q 2.39577
Q 3.59441
ω 251.5246
Node 320.6002
m 337.4513
n 0.1901
Epoch 2460800.5
nobs 5256
nopp 47
Years observed 1921-2025
rms 0.68
Best values
[raw, vot]

Value Standard error
Parent
 
ap 2.997
ep 0.224
sin(ip) 0.213
G 0.150
H 9.790
Mass
D 63.35 0.434
pV 0.052 0.0015
Value
Rotational Period 16.400
Period quality 2+
Spectral Class X
Spectral Class Score 9.800
Proper elements data
[raw, vot]

ap ep sin(ip) Author Reference Method
2.9973 0.2243 0.2126 Novakovic_Radovic_Todovic 2003A&A...403.1165K Numeric-Nov-2024
Diameter data
[raw, vot]

Value Uncertainty up Uncertainty down Author Reference Method
52.16 14.000 14.000 Nugent 2016AJ....152...63N NEATM
52.87 17.360 17.360 Masiero 2021PSJ.....2..162M NEATM
56.29 17.640 17.640 Nugent 2016AJ....152...63N NEATM
58.31 1.705 1.705 Ryan&Woodward 2010AJ....140..933R IRAS-STM
59.68 5.970 5.970 Ali-Lagoa 2018A&A...612A..85A NEATM
60.98 0.740 0.740 Usui 2011PASJ...63.1117U NEATM
63.49 0.740 0.740 Masiero 2014ApJ...791..121M NEATM
64.45 6.450 6.450 Ali-Lagoa 2018A&A...612A..85A NEATM
66.74 1.227 1.227 Masiero 2011ApJ...741...68M NEATM
67.56 6.760 6.760 Ali-Lagoa 2018A&A...612A..85A NEATM
69.17 1.400 1.400 Tedesco 2002AJ....123.1056T STM
75.07 4.208 4.208 Ryan&Woodward 2010AJ....140..933R IRAS-NEATM
Albedo data
[raw, vot]

Value Uncertainty up Uncertainty down Author Reference Method
0.042 0.0050 0.0050 Ryan&Woodward 2010AJ....140..933R IRAS-NEATM
0.049 0.0020 0.0020 Tedesco 2002AJ....123.1056T STM
0.050 0.0300 0.0300 Nugent 2016AJ....152...63N NEATM
0.051 0.0100 0.0100 Ali-Lagoa 2018A&A...612A..85A NEATM
0.052 0.0057 0.0057 Masiero 2011ApJ...741...68M NEATM
0.055 0.0260 0.0510 Masiero 2021PSJ.....2..162M NEATM
0.057 0.0110 0.0110 Ali-Lagoa 2018A&A...612A..85A NEATM
0.060 0.0100 0.0100 Masiero 2014ApJ...791..121M NEATM
0.060 0.0300 0.0300 Nugent 2016AJ....152...63N NEATM
0.066 0.0130 0.0130 Ali-Lagoa 2018A&A...612A..85A NEATM
0.069 0.0041 0.0041 Ryan&Woodward 2010AJ....140..933R IRAS-STM
G data
[raw, vot]

Value Uncertainty up Uncertainty down Author Reference Method
0.15 MPC-2023-12-94 MPC-2023-12-94 Phot
H data
[raw, vot]

Value Uncertainty up Uncertainty down Author Reference Method
9.79 MPC-2023-12-04 MPC-2023-12-04 Phot
Periods
[raw, vot]

Value Quality Side real or Synodic Author Reference Method
10.85 2 Synodic Behrend LCDB Lightcurve
10.862 1 Synodic Behrend LCDB Lightcurve
16.43 2+ Synodic Alvarez 2012MPBu...39...21A Lightcurve
8.215 2 Synodic Brines 2017MPBu...44..145B Lightcurve
Spectral Class Data
[raw, vot]

Class 1 Class 2 Probability of Class 1 Probability of Class 2 Taxonomy Wavelength Author Reference Method
P 0.900000 Mahlke VIS Mahlke 2022A&A...665A..26M SPEC
X 0.800 Bus-Demeo VIS Sergeyev 2022A&A...658A.109S PHOT
Xk Bus VIS Lazzaro 2004Icar..172..179L SPEC
X Tholen VIS Lazzaro 2004Icar..172..179L SPEC