Open AccessMeteoroid rotation and fireball flickering: a case study of the Innisfree fireball
Author(s) -
Beech Martin
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04520.x
Subject(s) - meteoroid , physics , meteorite , meteor (satellite) , astrophysics , rotation (mathematics) , brightness , asteroid , light curve , astronomy , atmosphere (unit) , rotation period , stars , geometry , meteorology , mathematics
Some 5 per cent of bright meteors show rapid, quasi‐periodic brightness variations. It is argued that this effect, observationally known as flickering, is a manifestation of the rotational modulation of surface mass loss through ablation of a non‐spherical meteoroid. We develop a set of time‐dependent, single‐body ablation equations that include the effect of cross‐section area modulation. We present a discussion of the effects that the rotation of a non‐spherical meteoroid has on the resultant meteor light curve, and we look in depth at the data related to the fireball associated with the fall of the Innisfree meteorite. We find that the parent object to the Innisfree meteorite was spinning at a rotation frequency of 2.5 Hz when it encountered the Earth's upper atmosphere. We also find that the Innisfree parent body had an initial mass of about 20 kg and that the ratio of its semiminor and semimajor axes was about 0.5.