Issue |
A&A
Volume 371, Number 2, May IV 2001
|
|
---|---|---|
Page(s) | 652 - 666 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20010409 | |
Published online | 15 May 2001 |
The effect of stellar activity on the Li I 6708, Na I 5896 and K I 7699 Ålines*
A comparison with the Pleiades, field stars and the Sun
1
Departamento de Física Teórica, C-XI-506, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
2
Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain e-mail: rgl@ll.iac.es
3
Departamento de Astrofísica, Universidad de La Laguna, Av. Astrofísico Francisco Sánchez s/n, 38071 La Laguna, Tenerife, Spain
4
Osservatorio Astronomico di Capodimonte, Via Moiariello, 16, 80131 Napoli, Italy e-mail: severino@na.astro.it; gomez@na.astro.it
Corresponding author: D. Barrado y Navascués, barrado@pollux.ft.uam.es
Received:
9
June
2000
Accepted:
12
March
2001
An analytical model has been developed to empirically study the effects of
stellar spots and faculae on the observed equivalent
widths of
Li i 6708, Na i 5896 and K i 7699 Ålines
(and abundances in the case of lithium)
in late-type stars, taking into account
the changes in the observed magnitudes and colors.
Solar spectra corresponding to
different active regions are used as input data and a range of filling factors
are applied to simulate the surfaces of stars with different levels of
activity. Detailed comparisons between predicted and observed photometric
colors and equivalent widths are made for late-type stars of the Pleiades and the field. The
observed dispersions in K i and Li i equivalent widths for Pleiades stars can be
partially accounted by the simultaneous effects of activity on colors and the
line formation, indicating that the lithium-rotation connection suggested for
~ Pleiades stars could be due in part to the stellar
activity. However, under realistic values for the filling factors, only a
small portion of the observed spread could be explained by these effects.
Key words: Sun: activity / Sun: faculae, plages / sunspots / stars: abundances / stars: activity / stars: late type
© ESO, 2001
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