Habitable Zones Near and Far


In this assignment students will be required to investigate properties of habitable zones throughout a galaxy. Using their knowledge, they will uncover how planets relate to their central star.

Goal/s: Calculate how the temperature of a planet depends on the properties of the central star and the orbital properties of the planet.

Class: Astro 16

Introduction/Background: This exercise is preceded by a 20 minute mini-lecture addressing concepts pertaining to habitable zones, and how the distance of a central start can dictate the necessary conditions to sustain life on a given planet. Following the lecture, students are encouraged to split into diverse, self-selected small groups of about 6-8 people. This problem is to be completed on a blackboard.


1) Students select their groups.

2) The instructor administers the worksheets.

a.) Students are asked to recall the process of stellar scaling relations.

b.) Students make various calculations regarding radius, temperature, and luminosity of a planet and a star.

c.) Calculate the energy per time the planet receives from the star.

d.) Calculate the energy per time the Earth radiates as a blackbody.

e.) Determine how the temperature of the planet will change if it were smaller/larger.

f.) Determine the how the habitable zone distance is influenced by stellar mass.

3) As students work in groups, circulate around the room, noting the progress of each group, ensuring that each student is engaged. Students can refer to notes from the lecture in order to complete the activity.

Follow-up: Groups that don’t complete the assignment in class can turn it in during the next class meeting.

Comments: Teaching Fellows/Assistants will float to each group, answering questions and posing new ideas, guiding students inquiry, without creating a culture of dependency. This inverted lecture style creates a space for students to assume the role of instructor, and demonstrate their knowledge in a visually interactive way.

Materials/Resources: Blackboard/chalk or whiteboard/dry erase markers.

worksheet.pdf833 KB