On the Spectrum of the Herbig Be Star HD 200775

Abstract

On the basis of high^-dispersion spectra (I. Appenzeller, C. Bertout) and other observational material HD 200775 has been reanalyzed using I Her as a comparison star. By comparing the depths in the wings of Hy and H6 and the equivalent widths of Hel-lines with predictions from model atmospheres we find for both stars T e ff = 17000 -l(j)00 k (in the scale of Kurucz 1 models, 1979) and log (g cm s~l) = 3.6 -0.3 corresponding to a spectral type of B3V. With a colorexcess E B _y = 0.56 and the standard interstellar reddening also the continuum energy distribution of HD 200775 corresponds to the above photospheric para meters if one allows for some circumstellar emission. However, the interstellar absorption features (4430 A and 2200 A) are of unusual weakness. The strength of the Ha emission requires either a nonthermal source of energy or a substantial rate of photo ionization from the level n = 2. We tend to conclude that for this second reason the dilution factor in the Hll-region cannot be less than 10" , a conclusion which is in accord with the finding that the radio emission at X = 2 cm is less than 0.3 mJ which also indicates a very compact Hll-region.M. Jaschek and H.G. Groth (eds.), Be Stars, 499.

A spectroscopic study of the open cluster NGC 6250

“…It allows the calculation of detailed Stokes IQUV spectra in the Sun and in rotating and/or pulsating stars with dipolar and quadrupolar magnetic geometries. Software archaeology reveals that cossam harks back to the algol 60 code analyse 65 by Baschek et al (1966) and to the fortran code adrs3 by Chmielewski (1979). cossam is the first code of its kind that takes advantage of the sophisticated concurrent constructs of the ada programming language that make it singularly easy to parallelize the line synthesis algorithms without having recourse to message passing interfaces.…”

Chemical Abundances and Rotation Velocities of Blue Horizontal‐Branch Stars in Six Globular Clusters

“…In order to simultaneously solve for chemical abundances, microturbulent velocity , and projected rotation velocity v sin i, we have developed an iterative spectral synthesis fitting routine, which scans through a range of parameter space in batch mode, comparing spectra calculated by the LINFOR/LINFIT spectral synthesis package (Baschek, Holweger, & Traving (1966), subsequently modified by M. Lemke) to the observed spectra. Thermal, turbulent, and rotational broadening are included in the line profiles computed by LINFOR, and the synthetic spectra are then Buonanno et al 1985; (6) Rosenberg et al 2000b;Rosenberg et al 2000a; (7) Walker 1994; (8) Buonanno et al 1984; (9) Ferraro et al 1997b; (10) -ðT eff ; log gÞ solution for cool star M68/W464.…”