Models for the Transition Regions of gamma Draconis and Capella based on Hubble GHRS Spectra

Details Models for the Transition Regions of gamma Draconis and Capella based on Hubble GHRS Spectra Models for the Transition Regions of gamma Draconis and Capella based on Hubble GHRS Spectra

Dec 1992

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992aas...181.5107l&link_type=abstract

American Astronomical Society, 181st AAS Meeting, #51.07; Bulletin of the American Astronomical Society, Vol. 24, p.1206

Physics

Quantum Physics

1

Scientific paper

We have analyzed Goddard High Resolution Spectrometer observations of the hybrid-chromosphere star gamma Draconis (K5 III) and the long-period RS CVn system alpha Aurigae (Capella, G8 III + G0 III) observed at phase 0.26. Here we discuss the low resolution spectra obtained with the G140L grating that cover the 1057--1943 Angstroms region for gamma Dra and the 1161--1710 Angstroms region for Capella. We identify the emission lines and tabulate their observed fluxes and surface fluxes. Assuming that most of the emission line flux from Capella is produced by the G0 III star, we find that the surface fluxes of the transition region lines are typically 400 times larger than for the Sun and only a factor of 4 below the saturation limit. By contrast, the surface fluxes of the transition region lines for gamma Dra are a factor of 40 times smaller than for the Sun and are the smallest values ever detected for a star. We have derived models for the transition regions of gamma Dra and the Capella G0 III star covering the temperature range 20,000--150,000 K by an emission measure analysis of the emission line surface fluxes. One interpretation of the gamma Dra model is that the high-temperature material occurs in magnetically heated active regions that cover ~ 10(-4) by area of the surface. Another interpretation is that the very small amount of hot material occurs in a few very strong shock waves that can occur when there is a stochastic distribution of acoustic wave periods. This work is supported by NASA Interagency Transfer S-56500-D to the National Institute of Standards and Technology. (1) Staff member, Quantum Physics Division, National Institute of Standards and Technology.

Affiliated with

Also associated with

No associations

Rating

Models for the Transition Regions of gamma Draconis and Capella based on Hubble GHRS Spectra 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 Models for the Transition Regions of gamma Draconis and Capella based on Hubble GHRS Spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Models for the Transition Regions of gamma Draconis and Capella based on Hubble GHRS Spectra will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1111062