The Effect of Velocity Gradients on Cepheid Spectra: Models

Details The Effect of Velocity Gradients on Cepheid Spectra: Models The Effect of Velocity Gradients on Cepheid Spectra: Models

Dec 1995

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995aas...18710207b&link_type=abstract

American Astronomical Society, 187th AAS Meeting, #102.07; Bulletin of the American Astronomical Society, Vol. 27, p.1429

Other

1

Scientific paper

High resolution observations of Eta Aql and other Cepheids have revealed differences in the radial velocity curves from the spectral lines of elements having differing ionization states and excitation energies. The effect of atmospheric velocity gradients on these differential radial velocity curves is investigated with synthetic spectra calculated from model hydrostatic stellar atmospheres appropriate for Cepheids. A number of velocity gradients have been kinematically introduced in these models. It is shown that a significant velocity gradient is needed near the phase of maximum infall velocity to account for the line profile asymmetries and velocity differences observed in the spectrum of Eta Aql. The effect of this velocity gradient is to reduce the amplitude of the pulsational velocity curve at optical depth tau = 2/3 by 20% and to decrease the gamma velocity by 2 km/sec relative to the standard assumption of a co-moving atmosphere. The Barnes-Evans method has been used to analyze Eta Aql, taking this velocity gradient into account. The resulting radius and distance are reduced by about 17%, compared to the result found earlier for a co-moving atmosphere, while the mean Mv changes from -4.47 to -4.08.

Affiliated with

Also associated with

No associations

Rating

The Effect of Velocity Gradients on Cepheid Spectra: Models 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 The Effect of Velocity Gradients on Cepheid Spectra: Models, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Effect of Velocity Gradients on Cepheid Spectra: Models will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1256642