10: Exoplanet Detection - Transit Method

Astronomy Lab Manual · LibreTexts

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    Lab Overview

    Lab Goals

    The goal of this lab is to develop the scientific practices of collecting and interpreting data:

    • Make connections between measured data and planetary orbit positions/velocities
    • Identify patterns relating mass (planet and star), orbital distance, orbital speed, and measured light properties for transit measurements

    Equipment and Setup

    This lab requires the following equipment on each table.

    • Computers with internet for simulation

    Submission Instructions

    Submit a brief lab report that includes the following sections:

    Results

    • Light Curve Drawings
    • Data

    Discussion

    Write your answers to the Discussion Questions using the Claim-Evidence-Reasoning format.

    Background Information

    Light Intensity

    clipboard_ed7dff9661f39323edab35d534b81162d.png

    We can see and measure the light from other stars in our galaxy. Planets are smaller and darker, so we cannot see them directly. However, we can detect them when they pass in front of a star and cast a small shadow that reduces the total amount of light our telescopes receive. The transit method detects planets and uses the characteristics of the light curve to infer properties about the planet and its orbit. A Normalized Flux of 1.000 is the full start light. The other values on the graph can identify the percent of starlight that reaches us (0.990 = 99% of the light or 1% of light is blocked).

    Lab Instructions

    Simulation Setup

    Open the Transit simulation from the University of Nebraska Astronomy Education website:

    Part 1 - Transit Measurements

    Procedure

    1. Animate the orbit by moving the phase slider from one end to the other.

    Make sense of the model

    1. Where is the planet when the normalized flux is 1.000?
    2. Where is the planet when the normalized flux is below 1.000 and a flat line?
    3. Where is the planet when the graph slants down or up?

    Part 2 - Planet Properties

    Procedure

    1. Set inclination to 90o
    2. Choose one slider in the Planet Properties controls at a time and make changes. Examine effects on the orbit, the light curve, and the period of the eclipse
    3. Repeat for the other slides

    Discussion Questions

    1. Make a claim about the effect of each planet property on each of the following:
      1. Light Curve depth
      2. Light Curve eclipse time
      3. Total Orbital Period

    Part 3 - Star Properties

    Procedure

    1. There is only one star property (mass). Change it without changing anything else and examine effects on the orbit, the light curve, and the period of the eclipse

    Discussion Questions

    1. Make a claim about how the mass of the star does/does not affect:
      1. Light Curve depth
      2. Light Curve eclipse time
      3. Total Orbital Period





    This page titled 10: Exoplanet Detection - Transit Method was last modified on Tue, 06 Oct 2026 03:17:33 GMT and is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Andrew Totah-McCarty.