Black Holes in my Classroom How do We Detect Stellar Mass Black Hole Candidates?

Link to the demonstrator: in English


Age: 14-18

Duration: 3 hours

Equipment: PC with internet connection


Contact details

Author: Dr. Rosa Doran (NUCLIO)
Contact: info[at]frontiers-project[dot]eu



This demonstrator introduces the concept of black holes and how difficult it is to find them. Students are introduced to a method of detecting black holes in eclipsing binary systems – systems formed by a visible star and an eclipsing companion. Real images will be used to look for changes in the starlight that might result due to the presence of a companion. Students will learn how to use a specific image software to perform photometry on the images and will create a graph of brightness variation. The analysis of the light curve will allow students to estimate the orbital period of the companion and, given a relation between several parameters of the known star and the companion’s mass, they will estimate the minimum mass of the unknown companion and decide if it is a strong candidate to be a black hole. Students can present their work to the class and discuss how they compare with the most accurate results that astronomers have.


Learning outcomes:

  1. Teach students about black holes and how to detect them.
  2. Allow students to understand the science and methodology behind the detection of black holes.
  3. Introduce basic concepts of Astronomy and Image Processing


Prior knowledge:

  • Basic Astronomy knowledge of stars and their lives
  • Excel (charts)
  • Kinematic’s concepts such as: radial velocity, orbital period, Keppler’s Law


Concepts introduced:


  • Black holes
  • Luminosity
  • Photometry
  • Graph analysis



Learning intentions:

By the end of this descriptor, students should be able to:

  • Define a black hole
  • Explain an eclipsing binary system
  • Describe a method to collect luminosity data
  • Examine images using the salsa J software
  • Form conclusions about a binary system from a light graph


Key activities:

  1. Videos to engage – possible edpuzzle 
  2. Explaining the light curve
  3. Practical formation of a light curve
  4. Salsa J – examination of 3 stars
  5. Analysis and explanation – activity handout possibly
  6. Final report



By the end of this descriptor, students should be able to answer the following: 

  1. Write a couple of sentences describing what you learned about black holes (why they are black, the different types of black holes, how black holes are formed).
  2. It is difficult to observe black holes. Why? Can you look for any kind of black hole candidate using the light curve?
  3. Why do you need to measure the period of the light curve when you are studying binary eclipsing systems?
  4. How do you determine if the compact object is a stellar black hole candidate or not?

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