Monitoring young stars

This page assumes you have read the Finding cluster members article.

The IC 2118 team has embarked on a campaign to monitor some of the candidate TTauri stars that we found using Spitzer data. They are using ground-based telescopes to see if the stars vary.

This page will be filled out more with general information about the project, but you can watch them work here.

Time series analysis

What is time series analysis?

The term "time series analysis" refers to the analysis of any data set where you have many measurements over some amount of time, for example, watching the same star many times per night over many nights.

Time series analysis can be very powerful, and is used in many different fields of science, from tree rings to weather to sunspots to variations of young stars. There is a LOT of information out there on the web with information on analysis of time series data, but everything I found jumped into heavy-duty programming, math, and statistics without much explanation - e.g., the information is aimed at professional scientists.

Data to play with

raw data to practice with (data taken by Mr. Spuck and students) - images on which you can measure photometry.

luisa's light curves (data taken by R. Makidon and used by L. Rebull for part of her thesis - just the reduced photometry time series from many 100s of images, for ~5000 stars. Read the "readme.txt" file in order to understand what you are looking at.

Where are we looking?

Spot has a feature (as does Leopard for that matter) where you can overlay outlines of the Spitzer instrument fields of view on a larger image, and that way you can see where in the sky you are pointing. If you would like to see where in the sky you are looking with your ground-based telescope for your monitoring project, you can also do this in Spot!

1. Download, install, and start Spot.
2. Create a target. Click on the bullseye icon, or pick "new target" from the "targets" menu. Enter in a name, and RA/Dec for a part of sky near your target. Tip: if you are using a well-known name, just enter the name, and ask Spot to use Simbad or NED to obtain the RA/Dec for you.
3. Download a background image. Go to the "images" menu and pick an archive to use. Tips: ISSA is the IRAS all-sky survey, and will let you download an image up to 5 degrees on a side. 2MASS is the 2-micron all-sky survey, and will only let you download relatively tiny pieces of sky at one time. You can also load a fits image from your computer.
4. Ask Spot to overlay the field of view. After you have an image in place, go to the "overlays" menu and pick "generic focal plane". You will get a dialog box asking you the focal plane type (e.g., do you want it to draw a circle or a square?) and the size ("side/diameter") in arcseconds for the circle or square. You can also change the color it uses.

Voila! You can do this again and again on the same image - just keep creating new targets and asking it to overlay the focal plane at the location of each of your targets.