Manual.md

This section summarises the tool's options.

Getting started

Head over to the Release section and get the latest release. To run the application, you only need to download the .jar file from there.

Ensure to have installed Java version 11 or newer. The application should run on Windows, MacOS and Linux.

Graphical User Interface

To open the application the standard way, double click the .jar file or run java -jar stift.jar from the command line.

Input

Use one of the following ways of inputting the data:

• Click the graph, the (x, y) coordinates of cursor's position give input values.
• Fill in the form on the right.
• Upload data file via menu Data > Upload input data file.

The uncertainty is computed from the Monte Carlo simulation on a thousand of points with a normal distribution. To turn off computing the uncertainty and speed the estimation up, uncheck the Compute uncertainty option. Uncertainty that is equal to 0 is overwritten to uncertainty coming from points in evolutionary line.

To upload input data, provide a .txt file and comment out header lines with '#' symbol.

#TEMPERATURE	LUMINOSITY
3.944	1.508
4.053	2.383
... and more

or

#TEMPERATURE	LUMINOSITY	TEMPuncertainty	LUMuncertainty
3.944	1.508	0.014	0.023
4.053	2.383	0.008	0.027
... and more

attributes separated by space. Missing uncertainties attributes will be set to 0.

Grid (models)

To upload custom grid, navigate to menu Grid > Upload new grid. Any header lines need to start with '#' sign to be parsed correctly. Grid data need to be a) labeled (isochrones) or b) grouped by initial mass and sorted by evolutionary phase (evolutionary tracks). The GUI shows only a part of the grid data, but all points are taken into account when computing. Accepted format is a .txt file. Use space or ',' delimiter between attributes. To obtain correct uncertainty results, please follow the results table's header for specification of values representation:

#lgTeff[K]	lgLum[Lsun]	lgAge[yrs]	Rad[Rsun]	Mass[Msun]	Phase
3.66943	-0.72127	8.23306	0.66695	0.75000	5.00000
3.66932	-0.72112	8.26683	0.66741	0.75000	5.00053
3.66922	-0.72095	8.30172	0.66784	0.75000	5.00112
3.66912	-0.72077	8.33767	0.66828	0.75000	5.00179
... and more

if tracks' labels are missing, points are separated into tracks when the value of phase drops (as the data should be sorted by phase within tracks). If labels are provided:

#lgTeff[K]	lgLum[Lsun]	lgAge[yrs]	Rad[Rsun]	Mass[Msun]	Phase	Label
3.66943	-0.72127	8.23306	0.66695	0.75000	5.00000	1
3.66932	-0.72112	8.26683	0.66741	0.75000	5.00053	1
3.66922	-0.72095	8.30172	0.66784	0.75000	5.00112	1
3.66912	-0.72077	8.33767	0.66828	0.75000	5.00179	1
... and more

points with the same label (in a continuous block of data) create a track. This way isochrones can be loaded.

After successfull parsing of the grid file, you can specify which phase represents the ZAMS (this will help to estimate near-ZAMS points) and choose which phases you want to exclude from the data.

Default grid data is extracted from PARSEC STELLAR EVOLUTION CODE.

The phase labels in the default grid file are described here, the default grid in the StIFT uses these:

#Value	Phase	Description
4	NEAR_ZAM	This point is very near the ZAMS
5	MS_BEG	H burning fully active
6	POINT_B	Almost end of the H burning. Small contraction phase begins here for interm. & massive stars
7	POINT_C	Small contraction ends here and star move toward RG
8	RG_BASE	RG base
9	RG_BMP1	RGB bump in Low Mass Stars (marked also for other masses)
10	RG_BMP2	RGB bump end in Low Mass Stars (marked also for other masses)
11	RG_TIP	Helium Flash or beginning of HELIUM Burning in intermediate and massive stars

Filtering

For filtering the results in the table, use phase filter in the phase column header. Results filtered out won't appear in the export file.

For ignoring certain phases in the interpolation, restrict them using checkboxes. Keep in mind that the result can be estimated in the phase that is filtered out (for example if phase 6 is ignored but phases 5 and 7 are chosen as the nearest tracks).

Exporting

To export results that appear in the results table, use menu Data > Export data. In the export file, you will find estimated parameters together with their uncertainties and estimation method.

There are different estimation methods that could have been applied to estimate mean values - NONE means no method could resolve the parameters, STAR MATCH means the input point is too close to some of the points in the grid and therefore it copies this grid point's values. SIDE MATCH only implies that the point lies too close to a side of the 4-angled figure and was interpolated using only 2 of the neighbours. FULL ESTIMATION suggests the standard process of estimating was followed - all 4 neighbours were repetitively interpolated. ZAMS INSIDER means additional point had to be estimated along the ZAMS track before continuing to the standard estimation method - simply because no lower right neighbour was found in the grid. ZAMS OUTSIDER means that the point lies outside of the graph, but the input values' uncertainties hit inside the graph.

Text mode

Text mode serves mainly as a debugging tool as it prints intermediate results of the computation. This includes the neighbours used for estimation, evolutionary line, mean value and uncertainties. You can use it from the command line with command

java -jar stift.jar text TEMP LUM [TEMPunc LUMunc] [GRID_FILE]

where TEMP and LUM are input values of effective temperature and luminosity and optional arguments TEMPunc, LUMunc their uncertainties. Missing uncertainties are treated as 0. Missing grid file argument instructs the application to use the default grid.

Fast mode

Fast mode can be used for limited, but fully run from command line, computation. This mode processes input file and directly exports result. The command to run fast mode is following:

java -jar stift.jar fast INPUT_FILE [GRID_FILE] EXPORT_FILE_NAME

where grid file is optional argument and if missing, default grid is used.