On the maximum amplitude of harmonics of an asteroid lightcurve

0429291 - ASÚ 2015 RIV US eng J - Journal Article
Harris, A. W. - Pravec, Petr - Galád, Adrián - Skiff, B.A. - Warner, B. D. - Világi, J. - Gajdoš, Š. - Carbognani, A. - Hornoch, Kamil - Kušnirák, Peter - Cooney jr., W. R. - Gross, J. - Terrell, D. - Higgins, D. - Bowell, E. - Koehn, B.W.
On the maximum amplitude of harmonics of an asteroid lightcurve.
Icarus. Roč. 235, June (2014), s. 55-59. ISSN 0019-1035. E-ISSN 1090-2643
R&D Projects: GA ČR GAP209/12/0229
Grant - others:SAV(SK) Vega 1/0670/13; NASA(US) NNX13AP56G
Institutional support: RVO:67985815
Keywords : asteroids * asteroids rotation * photometry
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 3.038, year: 2014

Most asteroid lightcurves are dominated by the second harmonic of the rotation period, caused by elongated shape. However, if the shape is not very elongate, other harmonics may dominate, leading to ambiguity of which is the true rotation period. We argue from geometry that at low phase angle, harmonics other than the second with amplitude exceeding resp. 0.4 magnitude are nearly impossible, so lightcurves with larger amplitude than that suggest a unique period dominated by the second harmonic, unless the spin is complex, non-principal axis rotation. On the other hand, lightcurves with amplitude less than 0.2–0.3 magnitudes can be dominated by other harmonics, especially the 4th and 6th, so the period may be ambiguous unless odd harmonics can be found to identify the true rotation period. We present examples of each, low and high amplitude ambiguities.
Permanent Link: http://hdl.handle.net/11104/0234455