Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010apj...721..670g&link_type=abstract
The Astrophysical Journal, Volume 721, Issue 1, pp. 670-674 (2010).
Astronomy and Astrophysics
Astronomy
4
Convection, Hydrodynamics, Line: Profiles, Stars: Atmospheres, Sun: Granulation, Techniques: Spectroscopic
Scientific paper
The long-standing puzzle of reversed-C bisectors of spectral lines is addressed with the tools of the third-signature plot and bisector mapping. The F8 supergiant γ Cyg, which shows strongly reversed bisectors, is analyzed and found to have a monotonic decline in velocities with height in its photosphere, consistent with a convective overshoot region similar to what is seen for stars on the cool side of the granulation boundary. Further, a flux deficit is derived that is not unlike those for stars on the cool side of the granulation boundary, although the γ Cyg flux deficit is wider and peaks at a higher velocity. The reversed-C bisector shape is caused by a combination of a steep decline in velocities with height, as shown in the third-signature plot, with a flux deficit spanning only a fraction of the red wing of the line profiles, in contrast to cooler stars where the deficit extends over most of the red wing. Apparently no unusual velocity fields or other bizarre behaviors are needed to explain the granulation boundary; it stems more simply from the continuous changes of normal convective overshoot across the HR diagram.
No associations
LandOfFree
An Explanation of Reversed Spectral-line Bisectors does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An Explanation of Reversed Spectral-line Bisectors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An Explanation of Reversed Spectral-line Bisectors will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1558266