6 research outputs found
An extensive library of 2500-10500 Ang synthetic spectra
We present a complete library of synthetic spectra based on Kurucz's codes
that covers the 2500-10500 Ang wavelength range at resolving powers 20,000,
11,500 (GAIA), 8500 (RAVE), 2000 (SLOAN) and uniform dispersions of 1 and 10
Ang/pix. The library maps the whole HR diagram, exploring 51,288 combinations
of atmospheric parameters spanning the ranges: 3500 <= Teff <= 47500 K, 0.0 <=
log g <= 5.0, -2.5 <= [M/H] <= 0.5, [alpha/Fe] = 0.0,+0.4, xi =1,2,4 km/sec, 0
<= Vrot <= 500 km/sec. The spectra are available both as absolute fluxes as
well as continuum normalized. Performance tests and foreseen spectroscopic
applications of the library are discussed, including automatic classification
of data from surveys like RAVE, SLOAN, GAIA. The entire library of synthetic
spectra is accessible via http://archives.pd.astro.it/2500-10500/ or (for the 1
AA/pix version only)
http://gaia.esa.int/spectralib/spectralib1A/SpectraLib1a.cfmComment: A&A, revised versio
Broad-band photometric colors and effective temperature calibrations for late-type giants. I. Z=0.02
We present new synthetic broad-band photometric colors for late-type giants
based on synthetic spectra calculated with the PHOENIX model atmosphere code.
The grid covers effective temperatures T_eff=3000...5000K, gravities log
g=-0.5...+3.5, and metallicities [M/H]=+0.5...-4.0. We show that individual
broad-band photometric colors are strongly affected by model parameters such as
molecular opacities, gravity, microturbulent velocity, and stellar mass. Our
exploratory 3D modeling of a prototypical late-type giant shows that convection
has a noticeable effect on the photometric colors too, as it alters
significantly both the vertical and horizontal thermal structures in the outer
atmosphere. The differences between colors calculated with full 3D
hydrodynamical and 1D model atmospheres are significant (e.g., \Delta(V-K)~0.2
mag), translating into offsets in effective temperature of up to ~70K. For a
sample of 74 late-type giants in the Solar neighborhood, with interferometric
effective temperatures and broad-band photometry available in the literature,
we compare observed colors with a new PHOENIX grid of synthetic photometric
colors, as well as with photometric colors calculated with the MARCS and ATLAS
model atmosphere codes. (abridged)Comment: 30 pages, 21 figures, A&A in press. Table 2 can be obtained from the
CDS or directly from the author
Spectral analysis of two Perseid meteors
Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe