The goal is to use synthetic spectroscopic binary spectra to see how well we can recover radial velocities, rotation, temperature, etc.
- Given a flux ratio, a pair of PHOENIX spectra, a set of observation times, an a binary orbit (e=0 for now), we will use the broadening function (BF) technique to investigate how well we can recover individual radial velocity measurements, the semiamplitude K, and each star's rotational velocity vsini.
- To accomplish this, we use
create_fakedata.py
to create a simulated time series of double-lined stellar spectra. Comments within this program guide the user to set input spectra, light ratios, vsini, and simulated observation times. The user then chooses either OPTION 1 to read in a list of predetermined radial velocities or OPTION 2 to compute radial velocities based on orbital parameters. - The output of
create_fakedata.py
is twofold: (1) a series offakedata#.txt
two-column text files, one for each simulated SB2 observation (wavelength in Angstroms and normalized flux); and (2) a singlefd3_infile_fakebinary.obs
file formatted for use with the spectral disentangling program FDBinary/fd3 (wavelength in ln(Angstroms) followed by one column per simulated SB2 flux). - To run, edit the source code as desired, then simply type
python create_fakedata.py
. Dependencies: numpy, matplotlib, astropy, and PyAstronomy.
For this paper in progress: https://www.overleaf.com/1778823xdcyhk#/4451323/
Real observed spectra of the triple system TYC 3559 (KIC 8848288) are included in this repo. It is a nearly-stationary giant star and a subgiant star with an eclipsing brown dwarf companion. The spectra are a composite of the bright giant and the dimmer, fast-rotating, RV-variable subgiant.
- The program
BF_pythonTYC.py
is a customized copy of https://github.com/mrawls/BF-rvplotter/blob/master/BF_python.py - The output is
bfoutfile3.txt
(the broadening functions with a two-Gaussian fit) andrvs_revisited3_BF.txt
(the radial velocities), plus a few plots and some useful info written to stdout. - To run, edit
infiles.txt
,bjdfile.txt
, andgaussfit.txt
as necessary, then simply typepython BF_pythonTYC.py
. Dependencies: BF_functions (included), numpy, matplotlib, astropy, PyAstronomy, scipy, pandas, gaussfitter (https://github.com/keflavich/gaussfitter).
- Adjust flux ratios (and other parameters?) in
create_fakedata.py
- Run
BF_pythonTYC.py
for the series of simulated double-lined spectra and inspect the results - Repeat the above two steps as desired for different sets of simulated observations
- Attempt to run FDBinary/fd3 on one or more sets of simulated spectra and inspect the results (for more on this, see http://sail.zpf.fer.hr/fdbinary/ and https://github.com/mrawls/FDBinary-tools)