On The Hot Component Of The Supersoft X-ray Binary/Symbiotic Variable AG Dra

Other

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Scientific paper

AG Dra is a D-Type Symbiotic consisting of a metal-deficient K0-4 giant and a hot white dwarf with an orbital period Porb 550 days
The outburst recurrence time of AG Dra is every 15 years and the duration of the outbursts is 3 - 6 years. From the classification of the giant, a distance of 2.5 kpc has been estimated. The reddening has been estimated to be E(B-V) = 0.05. Greiner et al.(1997) established that the X-ray/FUV flux level of AG Dra is anti-correlated with the optical maxima.
The nature of the hot component (WD + disk?) and rate of accretion has never been determined from synthetic spectral models of high gravity photospheres or optically thick accretion disk models. We have combined archival FUSE +IUE spectra obtained in the same activity state (quiescence) and orbital phase (0.5) of the system. In our NLTE the model fitting, we fixed the inclination i = 41 degrees, and the white dwarf mass = 0.6 M&sun; (log g = 8) consistent with the lower masses inferred for the hot components in other symbiotic systems (Muerset et al.1991).
From the FUSE spectrum alone, with the distance of AG Dra fixed at 2.5 kpc, we obtain a best fit white dwarf model having Teff = 65,000K with a χ 2 = 4.597 and a best fit accretion disk model with Ṁ = 5 × 10-8 M&sun;/yr. If the distance is a free parameter,
then the best fitting accretion disk model (with a chi2 = 3.19) corresponds to Ṁ = 10-8 M&sun;/yr.This fit yields a distance of only 640 pc. Our model results for the combined FUSE +IUE spectra are also presented and discussed.
This work was supported in part by NSF grant AST0807892 to Villanova University.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

On The Hot Component Of The Supersoft X-ray Binary/Symbiotic Variable AG Dra 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 On The Hot Component Of The Supersoft X-ray Binary/Symbiotic Variable AG Dra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On The Hot Component Of The Supersoft X-ray Binary/Symbiotic Variable AG Dra will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1402468

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.