lte-codes	sterne	spectrum	ffit	sfit	grids	idlines
commands		spectrum

SPECTRUM v3

C.S.Jeffery, P.L.Dufton, D.J.Lennon, E.S.Conlon, 1974-2002

---

Summary

SPECTRUM will compute synthetic spectra, line profiles equivalent widths, specific intensities, assuming LTE, from model atmospheres of early-type stars. The program will read model atmospheres calculated by ATLAS (Kurucz), or by Sterne and can handle atmospheres of arbitrary chemical composition, including chemically stratified atmospheres. Other formats can be introduced.

Version 3 is driven by a flexible command interface. It allows for depth dependent microturbulent velocities, for depth-dependent radial velocity shifts and for pre-selection of the linelist according to a given model atmosphere. It is much more easily extensible than the original version. Version 3 should still work with original QUB format input files (Version 1), but these should be regarded as obsolescent and will not support any of the new features of the code.

Invocation

Spectrum [models [linelist [control [label] ] ] ]

sterne models	file containing model atmosphere in 2006 Sterne format
models	file containing one or more model atmospheres
linelist	file containing atomic and line data
control	file containing program control data
label	label for output data files

If any of these parameters are not provided, further information will be requested from the terminal.
If no file control is given, information will be requested from the terminal.
Output files are constructed by appending a label to the string label.

Commands

A summary of command syntax and sample input files may be found here.

Examples

• Synspec Comparison.   T=25000, log g=4.0, vt=0, 1400-1415A.
  a) NLTE model atmosphere, spectrum computed with SYNSPECv25 (black).
  b) LTE model atmosphere, same linelist in converted format, spectrum computed with SPECTRUM (red) using this input file and this linelist.
• Chi Lupi Test.   T=10500, log g=4.0, vt=0, 1409-1415A.
  b) GHRS observed spectrum (black), best-fit model from Leckrone et al. (1999, AJ 117, 1454) (green), spectrum computed with SPECTRUM convolved with 0.235 A gaussian (red), using this input file and this linelist.

Models

In addition to any models the user wishes to use, there are three sources of precomputed model atmospheres in the correct format.

1) ATLAS9: A limited grid of ATLAS9 v_turb=2 model atmospheres for B stars is supplied with the code and labelled

t[Teff/1000]g[log g*10].d No need to label the folder, simply give one of the following names

t10g25.d t10g30.d t10g35.d t10g40.d t10g45.d t10g50.d t105g40.d t11g40.d t115g40.d t12g25.d t12g30.d t12g35.d t12g40.d t12g45.d t12g50.d t125g40.d t13g40.d t14g25.d t14g30.d t14g35.d t14g40.d t14g45.d t14g50.d t15g40.d t16g25.d t16g30.d t16g35.d t16g40.d t16g45.d t16g50.d t17g40.d t18g25.d t18g30.d t18g35.d t18g40.d t18g45.d t18g50.d t19g40.d t20g30.d t20g35.d t20g40.d t20g45.d t20g50.d t21g40.d t22g30.d t22g35.d t22g40.d t22g45.d t22g50.d t23g40.d t24g30.d t24g35.d t24g40.d t24g45.d t24g50.d t25g40.d t26g30.d t26g35.d t26g40.d t26g45.d t26g50.d t27g40.d t28g35.d t28g40.d t28g45.d t28g50.d t29g40.d t30g35.d t30g40.d t30g45.d t30g50.d t31g40.d t32g40.d t32g45.d t32g50.d t33g40.d t34g40.d t34g45.d t34g50.d t35g40.d

2) STERNE2: Collect models from the Sterne2 grid.

3) STERNE3: In preparation.

Physics

Atomic bound-free opacities may be selected from one of (flag NOPTYP)
0) as in ATLAS (QUB opacity library),
1) as in ATLAS and supplemented by additional tables for C, C+, C++, C+++, N, N+, N++, N+++ (Peach 1970) (Kiel opacity library), and
2) as in STERNE using monochromatic absorption data from the Opacity Project (OP opacity library).
The selection of the opacity library is determined by the model atmosphere input file, the object being to maintain consistency in the continuous opacity sources between model atmosphere and emergent spectrum.

Radiative transfer is treated (flag NTRANS) assuming
1) no scattering and the source function is given by the Planck function
2) scattering and source funtion found by Avrett-Loeser method (obsolete)
3) scattering and source function solve using a Feautrier scheme (default).

History

Text files containing sequential notes on changes to various parts of the program since 1993 are available. These contain comments on features that may not be working correctly and other recent changes.

• 2001 -
• 1997 - 2001
• 1993 - 1997

---

This page is maintained by: 
Simon Jeffery (csj@star.arm.ac.uk) 
Last modified: Jul 10, 2007