SIMBAD references

2008AJ....135.2033G - Astron. J., 135, 2033-2037 (2008/June-0)

Asymmetries in the spectral lines of evolved halo stars.

GRAY D.F., CARNEY B.W. and YONG D.

Abstract (from CDS):

We do an initial reconnaissance of asymmetries of spectral lines in metal-poor field stars using high-resolution observations of four red horizontal-branch and 11 red giant branch stars taken with the coude spectrograph at the Canada-France-Hawaii Telescope. We find that (1) the shapes of the line bisectors for metal-poor stars hotter than 4100 K mimic the well-known C shape of bisectors for solar-metallicity stars on the cool side of the granulation boundary while (2) metal-poor stars cooler than 4100 K, or higher up the red giant branch than MV= -1.5, show bisectors with a reversed-C shape, similar to those for solar-metallicity stars on the hot side of the granulation boundary and similar to the reversed-C shape found in a previous study for the M-type supergiant Betelgeuse. The well-documented radial-velocity jitter of high-luminosity stars and the line bisector characteristics vary in concert up the red giant branch; both phenomena are probably signatures of large convection cells.

Abstract Copyright:

Journal keyword(s): convection - stars: oscillations - stars: variables: other - supergiants - techniques: spectroscopic

Simbad objects: 22

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