Study of exoplanets

(developed by C. Bot and T. Boch)

Uses the VizieR and Simbad services and TOPCAT .

This tutorial highlights the following functionalities: VizieR queries by UCDs, object selection in TOPCAT, SIMBAD query by scripts.

Find the data

• launch TOPCAT
• go to the VizieR webpage
  • We want to look for exoplanets catalogs containing informations on the period. To do so:
    • Query VizieR both by "Word matching" with the word "exoplanets" and by UCDs using the UCD TIME_PERIOD
  • perform a joined query of table 2 and 3 from the catalog of nearby exoplanets (Butler+ 2006)
  • select objects for which the minimum mass is greater than 7 Jupiter masses
  • save the result as a VOTable file

Explore the data and define a subset:

• load the VOTable in TOPCAT
  • display the data on the 3D sky grid; add a color scale (auxilliary axis) to the data points that is proportional to the period
  • display the data in a 2D plot of the periods versus the radii
  • In this plot, draw a region to define a subset of the exoplanets with the longest periods (click on the "draw a region" button, select the region on the plot and click again on the button to save the subset)
  • Back to the main TOPCAT window, select the new row subset and display the column metadata.
  • Redefine the columns in the subset table so that it contains only the names of the stars
  • save this subset to a file in CSV format

Query SIMBAD by list:

• go to the Simbad webpage
• go to the "identifier query" interface
• query a list of identifiers, using the CSV file saved before
• click on the object having the greatest number of bibliographic references
• look at the basic data available, the references, but also the different types of measurements...

Query SIMBAD by script:

• Go to the Simbad webpage and to the query by scripts interface

• copy/paste the following script:

format object form1 "%IDLIST(1) : %COO(A D) %OTYPE \n%bibcodelist(2000-2010)[%*\n]\n"
set radius 0.2s
query around 55 Cnc

• Here is some explanations about this script:
  • format object lets you define your own output format
  • %IDLIST enables you to get all the existing identifiers for an object. In this example, one will only get the main identifier thanks to the "1" in the options ()
  • the scripts is then asking to display the coordinates (%COO(A D)) and the main object type (%OTYPE) as defined in Simbad
  • this scrip will also give all the bibliographical references on each object, published between 2000 and 2010. This is performed using the option %bibcodelist(2000-2010). The formating options [%*\n] will give a display of only one bibcode per line
  • the line starting with set radius defines a research radius in a global manner (i.e. it will apply to all queries)
  • Finally, once the format and the query radius are defined, you can specify all the identifiers that you wish to query. A line like "query around 55 Cnc" has to be written for each object to query. To query by coordinates, one could instead write query coo 12 30 +40 50]
  • Hint: you can get help on the script syntax and the existing options at http://simbad.u-strasbg.fr/simbad/sim-help?Page=sim-fscript
• complement this script by querying 2 or 3 objects of your choice, taken in the CSV file
• if you wish to mask the script display in the output, as well as the execution details, add the following two lines at the beginning of the script:

output script=off
output console=off

• execute the script with the "submit" button
• once the result has been displayed, copy the list of bibcodes obtained for an object and query the ADS service by pasting it in the Bibliographic Code Query form at http://cdsads.u-strasbg.fr/bib_abs.html and submit

-- MarkAllen - 18 Dec 2009

-- CarolineBot - 20 Jan 2010