“Be happy for this moment. This moment is your life.” Omar Khayyám
EXOplanet MOdeling Package v7.0
Created by Jake Turner
Questions, comments, or concerns can be addressed to
jt6an(at)virginia(dot)edu
Download: On GitHub (https://github.com/astrojake/EXOMOP) or below. See below. Make sure you download the most updated version v7.0
Help: See the README.pdf file in the download for a description of the code and what it does.
WHAT IT DOES:
- Fits transit data using Levenberg-Marquardt (LM) least-squares techniques to a Mandel & Agol (2002) model
Finds robust errors using the Bootstrap Monte Carlo technique
- Fits transit data using a Differential Evolution Markov Chain Monte Carlo (MCMC) fit (ter Braak, 2006) and finds errors.
Program stops when chains are well-defined using the Gelman-Rubin Statistic (Ford 2006)
- Fits a linear or quadratic function to the OoT baseline simultaneously with the Mandel & Agol (2002) model for both the LM and MCMC methods
- Accesses the influence of red noise for both the LM and MCMC methods (uses the residuals from the respective method):
Prayer Bead Method (Residual-Permutation Method)
The method by Fernandez et al. (2009) but has updated to use the error bars from the residuals. Assumes a
Gaussian Distribution
The method in Todorov et al 2012 (APJ, 746, 111). Does not assume a Gaussian Distribution
Time-Averaging Method (Beta Method) (Pont et al 2006, 373, 231)
Wavelet Method (Carter & Winn 2009, APJ, 704, 51)
- Finds the asymmetry of the transit about the calculated mid-transit time
TO COMPILE:
Simply put these procedures in your IDL path
(eg. !PATH = Expand Path('+/home/jturner/data/EXOMOPv7.0:+/home/jturner/data/EXOMOPv7.0/sub') + ':' + !PATH)
INPUT REQUIREMENTS:
- Your transit file. This file needs to contain: Time (HJD), Normalized Flux, Error
- Input File: An example Input File called input_file.text can be found with the download. Copy this file
into your working directory and edit it. See README for full description.
- Limitations:
Time of transit needs to be input with only the ones place and the decimals (e.g. change 2454218.90003 to 8.90003)
TO RUN:
In an IDL command window, navigate to the directory containing
your transit file. Then, type:
.r Useful_Values.pro
.r Detrend_linfit.pro
.r Detrend_quadfit.pro
.r exomop_prayer.pro
.r exomop_mcmcv2.pro
.r exomop_wavelet.pro
.r EXOMOPv7.10.pro
EXOMOP70,'Input_file.text'
ENSURING YOU HAVE RELIABLE ERROR BARS:
- Pay attention to the Bayesian information criterion value (lower values are usually better).
- Check to make sure that the gauss.ps and gauss_prayer.ps plots are gaussian. If they are not, run your model with more/less fixed parameters
- The file FINAL_EVERYTHING.dat includes all parameter fits, respective errors, both red noise calculation results and residuals.
- It is recommend that you choose the method (LM or MCMC) that minimized the residuals
- Multiple your error bars from FINAL_EVERYTHING.dat for each parameter by the largest beta (either the global value or individual parameter betas)
- To get your final error bars multiple the error bars from step 3 by sqrt(Chi-Squared), where Chi-Squared is the Reduced Chi-Squared in
FINAL_EVERYTHING.dat file. Only do this if the Reduced Chi-Squared is greater than one.
LIMITATIONS:
- Does not fit for period
- Uses linear and quadratic limb darkening coefficients.
CITATIONS:
Main Papers (earlier versions): Pearson K. A., Turner J.D., Sagan T.G. 2013. Photometric observation of HAT-P-16b in the near-UV. New Astronomy. arXiv.1310.5397.
Main Paper (v7.0): Turner J.D. et al. 2016. Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transits. MNRAS, arXiv.1603.02587
Mandel K., Agol E., 2002, ApJ, 580, L171
Eastman, J., Gaudi, B.S., Agol, E., 2013. Pasp 125, 83, 1206.5798
* These programs ((EXOMOPv7.0.pro,model .t.pro,Useful Values.pro, Detrend lin.t.pro,Detrend quad.t.pro, bin.pro,beta model.pro,exomop chi2.pro,exomop mcmcv2.pro, exomop prayer.pro,exomop wavelet.pro) are free
*software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>