Measuring eclipsing binaries in the Kepler data set - Revision history

Rebull at 18:00, 13 December 2011

2011-12-13T18:00:48Z

Rebull: /* The Project -- What to Do */

2010-08-20T16:36:44Z

The Project -- What to Do

Rebull: /* The Project -- What to Do */

2010-08-20T16:36:09Z

The Project -- What to Do

Rebull: /* The Project -- What to Do */

2010-08-17T16:51:39Z

The Project -- What to Do

Rebull: /* 2) Obtain your folded light curves */

2010-08-17T16:49:01Z

2) Obtain your folded light curves

Rebull at 16:47, 17 August 2010

2010-08-17T16:47:33Z

Rebull at 05:40, 12 August 2010

2010-08-12T05:40:43Z

Rebull: /* References and additional files */

2010-08-12T04:43:31Z

References and additional files

Rebull at 03:57, 12 August 2010

2010-08-12T03:57:43Z

Rebull at 03:53, 12 August 2010

2010-08-12T03:53:22Z

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 ==Outline==
-Start with newly published Kepler binary list ([http://adsabs.harvard.edu/abs/2010arXiv1006.2815P Prsa et al. 2010]) and use the [[What is a periodogram? | NStED periodogram service]] to investigate the light curves and make folded light curves (e.g., plot the light curve against orbital phase rather than time).
+Start with newly published Kepler binary list ([http://adsabs.harvard.edu/abs/2010arXiv1006.2815P Prsa et al. 2010]) and use the [[What is a periodogram? | NASA Exoplanet Archive periodogram service]] to investigate the light curves and make folded light curves (e.g., plot the light curve against orbital phase rather than time).
 [[image:binary3.gif]]
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 Binary star systems are of tremendous value to astronomy because of the wealth of direct measurements of stellar properties they can provide. They are also ubiquitous: only around half of stellar systems are lone single stars. In a survey for extrasolar planets, one will inevitably encounter them, and they can be valuable discoveries in themselves. Furthermore, since there are so many, one should probably not overlook the fact that planets may be present in binary systems, so it is good to understand them!
-The Kepler data taken to date is estimated to have of order ~1% occurrence rate of eclipsing binaries. Here you will be working with the Kepler data for these binaries to understand how and what binary parameters can be measured using time-series photometric data. You will be using the [[Accessing Kepler and CoRoT data | NStED database]] and [[What is a periodogram? | periodogram tools]] to access the data and produce folded light curves, and then using the program ‘Binary Maker’ to model the systems.
+The Kepler data taken to date is estimated to have of order ~1% occurrence rate of eclipsing binaries. Here you will be working with the Kepler data for these binaries to understand how and what binary parameters can be measured using time-series photometric data. You will be using the [[Accessing Kepler and CoRoT data | NASA Exoplanet Archive database]] and [[What is a periodogram? | periodogram tools]] to access the data and produce folded light curves, and then using the program ‘Binary Maker’ to model the systems.
 =Background=
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 =Resources=
-*NStED database: http://nsted.ipac.caltech.edu
+*NASA Exoplanet Archive: http://exoplanetarchive.ipac.caltech.edu
 *Binary Maker 3: Software -- CD and bundled documentation; also see http://www.binarymaker.com/
 *Bradstreet 2005, ‘Fundamentals of Solving Eclipsing Binary Light Curves Using Binary Maker 3’ : http://adsabs.harvard.edu/abs/2005SASS...24...23B  (essentially the same as chapter 11 in the manual for Binary Maker)
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 ==2) Obtain your folded light curves==
-*Access the NStED Kepler database:
+*Access the NASA Exoplanet Archive Kepler database:
-**Point your web browser to http://nsted.ipac.caltech.edu/
+**Point your web browser to http://exoplanetarchive.ipac.caltech.edu/
 **Click ‘Kepler Public Data’. Here you can see all the various options for querying the Kepler public data catalogue in various ways. Since we already have our list of stars of interest, we only need to ‘Retrieve Star Light Curve by ID’.
 **Enter the Kepler star ID for one of your binary systems. For convenience, the list of Kepler IDs for binaries in Prša et al. 2010 is given below. Click ‘View’
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 ***'''Normalize the flux to the maximum flux value''' (or somewhere near the maximum). This is not strictly necessary, since there are options in Binary Maker to scale the model light curves to any normalization level rather than the default 1. However, if you go that route, you need to remember to change the y-axis tick-mark spacing by hand to something sensible first – otherwise it will try to draw ~1,000,000 tick marks, and this appears to hang the system. You have been warned...
 ***'''Shift the phases so that 0 phase occurs at the minimum of the deepest (primary) eclipse.''' This is the typical convention for plotting folded light curves, and Binary Maker defaults to this for its models. The phase zero-point can be changed, however, in Binary Maker if necessary.
-***'''Restrict the phase range from 0.0—1.0'''. The NStED periodogram tool defaults to returning two foldings of the data (phase 0.0—2.0), so you may want to chop off the second half of the table, so that BM doesn’t plot everything twice. This is possibly not necessary, but it is probably safer to keep things clean.
+***'''Restrict the phase range from 0.0—1.0'''. The NASA Exoplanet Archive periodogram tool defaults to returning two foldings of the data (phase 0.0—2.0), so you may want to chop off the second half of the table, so that BM doesn’t plot everything twice. This is possibly not necessary, but it is probably safer to keep things clean.
 Feel free to use whatever tools you have available to perform this change of format. Excel may be a good choice, and should be available to most people. ''However, don’t spend too much time on this'' – the idea is simply to give you a taste of handling the data itself, and shouldn’t distract from the main point of the project. If it looks too time consuming, there is a simple Python script linked below which you can use to translate the files automatically:

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 *Each person in your group look at, say, 3-4 systems, chosen at random from the catalogue (or more if you find you have time!). Between you hopefully you will have enough results for some interesting analyses. For convenience, the entire Prša et al. list of Kepler IDs is included below.
 *Look at at least one system that is the same for everyone. This way you will be able to compare results, and learn about any possible degeneracies in your solutions. ('degeneracy' in this case means more than one set of completely different parameter values that give the same light curve shape.)  If everyone works on the same light curve, then variations in the parameters you get for the solution will yield an empirical estimate of the uncertainty in the parameter estimation process.
-*If you dig hard enough, you can find in the literature a list of binary parameters. But (a) the point of this is not to find the answers by other means, but by the methods laid out here; and (b) are those parameters as distributed really right? Can you get better values?
+*If you dig hard enough, you can find in the literature a list of binary parameters. But (a) the point of this is not to find the answers by other means, but by the methods laid out here; and (b) besides, are those parameters as distributed really right? Can you get better values?
 The following sections should get you going with what you need to do.

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 *Each person in your group look at, say, 3-4 systems, chosen at random from the catalogue (or more if you find you have time!). Between you hopefully you will have enough results for some interesting analyses. For convenience, the entire Prša et al. list of Kepler IDs is included below.
 *Look at at least one system that is the same for everyone. This way you will be able to compare results, and learn about any possible degeneracies in your solutions. ('degeneracy' in this case means more than one set of completely different parameter values that give the same light curve shape.)  If everyone works on the same light curve, then variations in the parameters you get for the solution will yield an empirical estimate of the uncertainty in the parameter estimation process.
 The following sections should get you going with what you need to do.

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 I would suggest that:
 *Each person in your group look at, say, 3-4 systems, chosen at random from the catalogue (or more if you find you have time!). Between you hopefully you will have enough results for some interesting analyses. For convenience, the entire Prša et al. list of Kepler IDs is included below.
-*Look at at least one system that is the same for everyone. This way you will be able to compare results, and learn about any possible degeneracies in your solutions.
+*Look at at least one system that is the same for everyone. This way you will be able to compare results, and learn about any possible degeneracies in your solutions. ('degeneracy' in this case means more than one set of completely different parameter values that give the same light curve shape.)  If everyone works on the same light curve, then variations in the parameters you get for the solution will yield an empirical estimate of the uncertainty in the parameter estimation process.
 The following sections should get you going with what you need to do.

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 Feel free to use whatever tools you have available to perform this change of format. Excel may be a good choice, and should be available to most people. ''However, don’t spend too much time on this'' – the idea is simply to give you a taste of handling the data itself, and shouldn’t distract from the main point of the project. If it looks too time consuming, there is a simple Python script linked below which you can use to translate the files automatically:
 *Upload your light curves to a place running Python with NumPy; there is also an IDL version there if you prefer that).
-*You should be able to find the program in the project resources directory, named ‘ipaclc2bm.py’. The program is aliased, so to convert the files, you simply need to run the command (in any directory):
+*The program is linked below, named ‘ipaclc2bm.py’. To convert the files, you simply need to run the command (in any directory): ipaclc2bm inputfilename
 *Copy the converted light curve back to your own computer.
 ==3) Model your binaries==

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 [[image:binary1.gif]] Eclipsing binary in Kepler data.
-[[image:binary2.gif]] Planetary transit in Kepler data.
+[[image:binary2.gif]] Planetary transit in MOST data.
 ==Project Goals==
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 *What degeneracies do you find, or can you think of, between the various parameters?
 *What kind of follow-up observations might help?
 Once you have a good fit,

← Older revision		Revision as of 05:40, 12 August 2010
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−	''Based on materials originally developed by Julian van Eyken (~~NStED~~/IPAC) for the [http://nexsci.caltech.edu/workshop/2010/ 2010 Sagan Exoplanet Workshop]. This group project was entitled "Measuring Eclipsing Binary Star Parameters from Kepler Data."''	+	''Based on materials originally developed by Julian van Eyken (NExScI/IPAC/Caltech) for the [http://nexsci.caltech.edu/workshop/2010/ 2010 Sagan Exoplanet Workshop]. This group project was entitled "Measuring Eclipsing Binary Star Parameters from Kepler Data."''

	=Quick Introduction & Overview=		=Quick Introduction & Overview=

← Older revision		Revision as of 04:43, 12 August 2010
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	[[media:prsa_binaries_list.txt\|Prsa Binaries List]]		[[media:prsa_binaries_list.txt\|Prsa Binaries List]]

−	[[media:lc-format-conversion.tar\| Light Curve Conversion tarball of IDL and Python scripts]]	+	[[media:lc-format-conversion.tar\| Light Curve Conversion -- tarball of IDL and Python scripts]]

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 Depending on the time available (for bonus points!), see if you can plot up histograms of interesting parameters, or find any interesting correlations between the various parameters. Compare these to the results in the Prša et al. paper. Do your results look consistent? E.g., can you partially reproduce some of the plots? Do you get consistent occurrence fractions of the different binary types?
-) Presentation
+==5) Presentation==
 Put together a presentation on your findings!  Examples of things you might want to discuss or think about are:

← Older revision		Revision as of 03:53, 12 August 2010
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	[[media:prsa_binaries_list.txt\|Prsa Binaries List]]		[[media:prsa_binaries_list.txt\|Prsa Binaries List]]
		+
		+	[[media:lc-format-conversion.tar\| Light Curve Conversion tarball of IDL and Python scripts]]