Convective Wavelength Shifts in the Spectra of Late-Type Stars
We present ultra-high resolution spectra for a set of nearby F-G-K stars on, or close to, the main sequence. The wavelength shifts of stellar lines relative to their laboratory wavelengths are measured for more than a thousand Fe I lines per star, finding a clear correlation with line depth. The obs...
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Main Authors | , , , |
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Format | Journal Article |
Language | English |
Published |
21.01.2002
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Subjects | |
Online Access | Get full text |
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Summary: | We present ultra-high resolution spectra for a set of nearby F-G-K stars on,
or close to, the main sequence. The wavelength shifts of stellar lines relative
to their laboratory wavelengths are measured for more than a thousand Fe I
lines per star, finding a clear correlation with line depth. The observed
patterns are interpreted as convective blue-shifts that become more prominent
for weaker lines, which are formed in deeper atmospheric layers. A
morphological sequence with spectral type or effective temperature is apparent.
Two K giant stars have also been studied. The velocity span between weak and
strong lines for these stars is larger than for the dwarfs and subgiants of
similar spectral types. Our results show that convective wavelength shifts may
seriously compromise the accuracy of absolute spectroscopic radial velocities,
but that an empirical correction may be applied to measured velocities. |
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DOI: | 10.48550/arxiv.astro-ph/0201355 |