Summary: Astronomy & Astrophysics manuscript no. Gl203 January 17, 2005
(DOI: will be inserted by hand later)
Line Broadening of EUV lines Across the Solar limb: A Spicule
Contribution?
J. G. Doyle 1 , J. Giannikakis 1,2 , L. D. Xia 1,3 and M.S. Madjarska 4,5
1 Armagh Observatory, College Hill, Armagh, BT61 9DG, N. Ireland
2 Sect. of Astrophysics, Astronomy and Mechanics, Dept. of Physics, Univ. of Athens, Athens 15783, Greece
3 School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
4 Max­Planck­Institut f˜ur Sonnensystemforschung # , Max­Planck­Str. 2, 37191 Katlenburg­Lindau, Germany
5 Department of Solar Physics, Royal Observatory of Belgium, Av. Circulaire 3, B­1180 Bruxelles, Belgium
Received date, accepted date
Abstract. Spectral lines formed in the solar transition region show an increase in the line width, peaking at #10,000 km above
the limb. Looking at a region o#­limb with no obvious spicules, the non­spicule region has a significantly smaller line width
above 6,000 km compared those taken in a spicule region. We suggest that this increase in line broadening is not due to small
scale random motions but rather to unresolved line shifts due to spicules and/or macro­spicules activity.
Key words. Sun: atmosphere -- transition region -- o#­limb -- line broadening -- spicules
1. Introduction
Line width measurements can provide important details on
small­scale mass motions and ion temperatures, and if coro­
nal lines are used, informations on coronal heating may be ob­

Source: Armagh Observatory

Collections: Physics