Fitting Light Curves
Read in an APT lightcurve and fit it with a planetary transit shape, given a pre-determined period, transit epoch, stellar mass, radius and temperature. Period & epoch in days, stellar mass and radius in solar units, temp in K.
pro fitlc, 'file.lc', t0, p, ms, rs, teff, trange=trange, binsize=binsize, lg=lg, rp0=rp0, i0=i0, sec=sec, si=si, wfit=1, adj=adj, noell=noell, nolin=nolin, not0=not0
Log-on to astro1.phys.unsw.edu.au, cd to /data/mgh/candid (these are the cands that passed stage 1 selection)
Optional parameters
* If si is given a value in [0,18], it is used as an index (column number counting from bottom) into the table at www.atlasoftheuniverse.com/startype.html (bottom of this page), to give ms, rs and teff (or whichever ones are not set already).
* trange specifies the time range (days) centered on t0 within which points will be used in the transit shape fit. Default is 0.2 days
* binsize is the binsize is in days, default is 0.01 days
* lg is log(g) for looking up limb-darkening parameters. Default 4.5
* rp0 is the starting planet-to-star radius ratio in the fit. Default is 0.1
* i0 is the starting inclination (deg) in the fit. Default is 87 deg
* sec: if this is set (sec=1 or /sec) the best-fit model for the transit is overplotted on the secondary window.
* wfit: if this is set, the best-fit model light curve is output to a file (named by replacing everything after the '.' in the input filename with 'fit.lc')
* adj: set this to a vector of catalogue magnitudes for stars within the photometry aperture, the first one being that of the assumed source of the signal (generally the brightest star in the aperture). The amplitude of the light curve will be scaled up to adjust for dilution from the additional light.
You specify a list of mags directly as a vector. This is done by directly including something like adj=[9.2, 10.4, 12.1] on the command line when running fitlc. In this case the target star's mag is 9.2, and the mags of the other stars in the aperture come after. You can have as many as you need in the list. Use the 2MASS J mags for this, as they are commonly available.
You can also first create a vector called adj by typing 'adj=[9.2, 10.4, 12.1]' by itself on the IDL command line, and then when you run fitlc, you can actually say 'adj=adj', which is a bit more compact.
* noell: if this is set, no ellipsoidal variations will be removed, even if there is a significant detection
* nolin: if this is set, no linear trend will be removed from the region around the transit (which is done by default)
* not0: if this is set, the t0 will be a fixed parameter in the fit. Otherwise it is allowed to vary.
Stellar Parameters by Spectral Type
| # | SpecType | Teff (K) | R_sun | M_sun | Absolute Mag | Bolometric Lum |
| 18 | O3 | 53000 | 15 | 120 | -6.0 | 1400000 |
| 17 | O5 | 45000K | 12 | 60 | -5.7 | 790000 |
| 16 | O8 | 35000K | 8.5 | 23 | -4.9 | 170000 |
| 15 | B0 | 30000 | 7.4 | 17 | -4.0 | 50000 |
| 14 | B3 | 19000 | 4.8 | 7.6 | -1.6 | 1900 |
| 13 | B5 | 15000 | 3.9 | 5.9 | -1.2 | 830 |
| 13 | B5 | 15000 | 3.9 | 5.9 | -1.2 | 830 |
| 12 | B8 | 12000 | 3.0 | 3.8 | -0.2 | 180 |
| 11 | A0 | 9500 | 2.4 | 2.9 | +0.6 | 54 |
| 10 | A5 | 8200 | 1.7 | 2.0 | +1.9 | 14 |
| 9 | F0 | 7200 | 1.5 | 1.6 | +2.7 | 6.5 |
| 8 | F5 | 6400 | 1.3 | 1.3 | +3.5 | 3.2 |
| 7 | G0 | 6000 | 1.1 | 1.05 | +4.4 | 1.5 |
| 6 | G2 | 5800 | 1.0 | 1.00 | +4.8 | 1.0 |
| 5 | G5 | 5700 | 0.92 | 0.92 | +5.1 | 0.79 |
| 4 | K0 | 5200 | 0.85 | 0.79 | +5.9 | 0.42 |
| 3 | K5 | 4300 | 0.72 | 0.67 | +7.4 | 0.15 |
| 2 | M0 | 3800 | 0.60 | 0.51 | +8.8 | 0.08 |
| 1 | M5 | 3200 | 0.27 | 0.21 | +12.3 | 0.011 |
| 0 | M8 | 2600 | 0.15 | 0.06 | +16.0 | 0.001 |