801 Helwerthia is a C-type asteroid orbiting in the Main belt near the Eunomia family. However, it is not a family member but an un-related interloper in the region because its composition is inconsistent with membership. Its diameter is about 33 km, its albedo around 0.038.[2] An international team of astronomers observed this minor planet photometrically in 2012, determining a rotation period of 23.93±0.01 h with an amplitude of 0.15±0.03 in magnitude.[3]

801 Helwerthia
Discovery
Discovered byMax Wolf
Discovery siteHeidelberg Observatory
Discovery date20 March 1915
Designations
(801) Helwerthia
1915 WQ; A924 OD;
1925 RG; 1970 GS1
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc101.08 yr (36918 d)
Aphelion2.8087 AU (420.18 Gm)
Perihelion2.4007 AU (359.14 Gm)
2.6047 AU (389.66 Gm)
Eccentricity0.078337
4.20 yr (1535.4 d)
47.6362°
0° 14m 4.056s / day
Inclination14.130°
185.973°
335.076°
Earth MOID1.41172 AU (211.190 Gm)
Jupiter MOID2.17333 AU (325.126 Gm)
TJupiter3.366
Physical characteristics
16.615±1.25 km
23.93 h (0.997 d)
0.0384±0.007
11.55

References

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  1. ^ "801 Helwerthia (1915 WQ)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 6 May 2016.
  2. ^ "Supplemental IRAS Minor Planet Survey". Archived from the original on 23 June 2006.
  3. ^ Pilcher, Frederick; et al. (October 2012), "Rotation Period Determination for 801 Helwerthia", The Minor Planet Bulletin, 39 (4): 222–225, Bibcode:2012MPBu...39..222P
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