lte_lines: assessed atomic data for optical analyses of B stars*
C.S. Jeffery,
Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, Northern
Ireland
* Philip Dufton was a substantial contributor to the original version of this data collection.
For calculating model spectra of early-type helium stars in LTE, we maintain a database of atomic data for, mostly, blue-visual absorption lines of light elements. The data is sorted with one file for each ion.
For each absorption line included, the database includes the wavelength, oscillator strength, radiative, collisional and van der Waal's damping constants (where available), the excitation energy of the lower-level in the transition, the mulitplet number (from Moore's revised multiplet tables). References for oscillator strengths and damping constants are also given where possible. The database is dynamic, with new lines being added as required. Some vetting is applied to ensure that data are reliable. Corrections and updates may be included at arbitrary times.
The linelist format used by the Belfast line formation code SPECTRUM is a convenient means of storing atomic data needed for LTE line formation calculations. A substantial amount of data of varying quality is available in the literature. This database aims to maintain 'recommended' values for various atomic data, alongside information on sources, in a uniform manner. It does not necessarily contain the 'best' data, although this is a long term aim.
A combined linelist can be constructed for use (eg) with SPECTRUM by concatenating the files for individual ions, or by running the the C-Shell script lte_line. All the files necesary to run lte_line are provided as a gzipped tar file.
The linelists were reformatted by Philip Dufton in 2001 November. Damping constants were converted to natural gammas. Damping constants and oscillator strengths are now stored as logarithms.
The original description of this database is at: Jeffery C.S., 1991, Newsletter on 'Analysis of Astronomical Spectra', No. 16, p. 17, with data sources being cited within the database. An updated desciption accompanies this webpage (Jeffery 2020)Information
| File | Contents |
 | "read.me" file containing original ascii text for WWW pages |
|
Description of format and contents of ion files |
|
List of references to atomic data stored in ion files |
|
gzipped tar file |
Linelists for individual ions
| Ion | I = 0 | II = + | III = ++ | IV = +++ |
| Helium | He I | He II | ||
| Lithium | Li I | |||
| Carbon | C I | C II | C III | C IV |
| Nitrogen | N II | N III | ||
| Oxygen | O I | O II | O III | |
| Neon | Ne I | Ne II | ||
| Magnesium | Mg II | |||
| Aluminium | Al II | Al III | ||
| Silicon | Si I | Si II | Si III | Si IV |
| Phosphor | P II | P III | P IV | |
| Sulphur | S II | S III | ||
| Chlorine | Cl II | |||
| Argon | A II | |||
| Calcium | Ca II | |||
| Titanium | Ti II | |||
| Chromium | Cr II | |||
| Iron | Fe I | Fe II | Fe III | |
| Nickel |
Atomic data for transitions in specific ions are stored in individual files (e.g. He1.d, C1.d, C2.d, .... ). The individual line data include atom and ion identifiers, wavelength, oscillator strength, electron and radiative damping constants, excitation potential of the lower level in a transition, a multiplet identifier, and reference codes. The data are currently given in the following format.
Column Description 1 Atomic number 2 Ionisation stage 3 Wavelength (Angstroms) 4 Oscillator strength log gf 5 Electron damping width: log gamma_e 6 Radiative damping width: log gamma_r 7 Van der Waal's damping width: log gamma_W 8 Excitation energy of lower level (electron Volts) 9 Multiplet identification 10 References for 4 -- 8
Notes
Where there is more than one entry for a given line, the recommended entry is entered normally. Other entries are preceded by a minus sign in the atomic identifier field. This is to preserve old data in the database. spectrum ignores these lines.
Many damping constants are obtained from classical approximation formulae: these are indicated by a dash in the column for references. Where not even this level of sophistication is achieved, an approximate value may have been entered. No reference is cited, and fewer significant figures are placed in the table. A substantial effort is still required to extend the damping constant data.
Major sources
- Linelists compiled by the Queens University of Belfast Hot Star group
- Linelists provided in the code of Uli Heber, atomic data is published for some of these lines by Heber 1983, AA 118,39, with references. Not all of the references have been entered. Much of the data is very old.
- A compilation by Kilian et al (1990), preprint - Munich. This compilation selectively lists data for lines with B star equivalent widths predicted to be greater than 10 mA, so is not complete for all multiplets, and only for wavelengths 4050 - 5060 Angstroms.
- Oscillator strengths from the Opacity Project.
- Where data have been essential for synthesizing B star spectra, additional lines have been extracted from Kurucz' linelists.
Modern Sources
The following non-exclusive list covers more extensive compilations of atomic data and linelists.| CHIANTI | An atomic database for spectroscopic diagnostics of astrophysical plasmas |
| Kurucz | Kurucz linelists |
| NIST | The NIST atomic spectra database |
| TIPbase | The Iron Project database |
| TMAD | The T\"ubingen Model Atom database |
| TOPbase | The Opacity Project database |
| VALD3 | The Vienna Atomic Line Database |
| VAMDC | The Virtual Atomic and Molecular Data Center |
Utilities
| lte_line | C-shell script to construct a composite linelist given specified ions |
| spectrum is much more powerful than the B-star tag suggests. It may be used to model a wide variety of stellar spectra in LTE and HSE, providing they are warm enough not to contain molecules. Consequentky, more estensive linelists may be reuqired to construct genuinley useful synthetic spectra. There are many sources of atomic data (see above); the following utilities (available on request) enable some of these to be incorporated with existing QUB linelists. | |
| vald_qub | A Fortran utility to convert linelists downloaded from the Vienna Atomic Line Database into the new QUB format. |
| synspec_qub | A Fortran utility to convert linelists in SYNSPEC format into the new QUB format. |
| lte_select | A Fortran utility to
manipulate QUB-format linelists. It starts by reading in an optional
initial linelist (QUB format) which will not be changed.
An additional linelist (QUB format) is read in, it may be in the
form of a SYNSPEC list, sorted by wavelength, or in some other order.
Individual lines may be selected using various criteria including
one or more of the following: wavelength region ions oscillator strength Examples of use: |
|
This page is maintained by: Simon Jeffery (simon.jeffery@armagh.ac.uk) Last modified: 01/04/20 |
The Armagh Observatory and Planetarium is not responsible for the content of external internet sites |