Is a 2004 Leonid meteor spectrum captured in a 182 cm telescope?^*

¹ Institute for Astronomy (IfA), University of Hawaii, 2680 Woodlawn Drive, Honolulu, Hawaii 96822-1897, USA e-mail: kasugats@ifa.hawaii.edu
² National Astronomical Observatory of the Japan (NAOJ), National Institute of Natural Science, 2–21–1 Osawa, Mitaka, Tokyo 181–8588, Japan e-mail: jun.watanabe@nao.ac.jp
³ Obseservatorino Astrofisico, 36012 Asiago (Vi), Italy e-mail: takashi.iijima@oapd.inaf.it

Received: 2 March 2007
Accepted: 13 June 2007

Abstract

Context.It has been thought that fast-moving meteor spectra consist of only two excitation temperature regimes: the 5000 K main component and another hot component at 10 000 K. This belief does not always satisfy observed spectra due to the lack of sufficient physical correlation among derived excitation temperatures, observed fluxes, upper energy levels (E_u), and Einstein A coefficients (A_ul) of each spectral emission line.

Aims.This work tries to correlate them and discovery new excitation temperature regimes in meteor spectra in the visual to near IR wavelength region.

Methods.We focus on the upper energy levels and Einstein A coefficients of observed spectral emission lines. A model fitting the first positive band of nitrogen () and total number of Si II under quasi-neutral conditions proved the key to identifying of new components.

Results.We have identified two new excitation temperature regions in meteor spectra. One is a Mid component at 8000 K for and another a Jet component above 10 000 K for Si II. This breakthrough has allowed us to reproduce the meteor spectrum.

Conclusions.The spectra of high-speed meteors may consist of more than two excitation temperature regions including the main, Mid, hot, and Jet components.