P09: Asteroid Light Curve

Observing Goals:

You will observe the light curve of a asteroid Useful Background and References:

• A list of currently “in the sky” asteroids is available at: https://in-the-sky.org/data/asteroids.php

• Here are a Jupyter Notebook and a csv data file which let you find properties of asteroid light curves (from the PSI Asteroid Light Curve Database)

• Make finder charts: https://theskylive.com/ (The search here is quite bad – but if you use google for the name of the asteroid, you can find the skylive link that way)

Observation Planning:

• Observation Time

  • You will be observing a HALF night. You will share your data with another group observing the other half of the night. * One group (Asteroid Light Curve 1) will use the B and V filter images * One group (Asteroid Light Curve 2) will use the V and R filter images

• Target Selection

  • Together with the other group, select a target that will reach its highest point in the sky at around 1:30am (half way between sunset and sunrise). Possible targets can be found using in the sky, and looking for relativelyy bright, short term variable, asteroids

• Observations

  • You will observe the asteroid in the B,V and R filters over the duration of the night

  • If possible, take standard star fields at the start, middle, and end of your observations to allow for calibration to the magnitude scale.

Data Analysis:

• Data Reduction Basic Steps

  • Visit the page Data Reduction Cheat Sheet

• Further for this project

  • Next you need to align all of your images – but do not combine them

  • For each filter you have been assigned, you will do relative photometry (measuring brightness) over time to create a light curve

  • Identify other, non-variable, stars in the field to use as reference

• Further Analysis for this project

  • Plot the corrected magnitude of the star as a function of time for each filter – note that you should get the observation time from the header of the image, and account for the length of the exposure!

  • (You can also investigate if the colour between bands changes over time)

Results:

Can you answer these questions with your work?

• What is the shape of the variability? Is it sinusoidal or some other shape?

• What is the period of the variability (the time between successive peaks or dips)?

• What is the total amplitude of the variability? Does it change with band?

• Does the asteroid’s colour change with time?

• What kind of asteroid is this? Why do these asteroids vary in this way?

Presenting your results:

• A1. Preparing a Scientific Poster

• A2. Preparing a Scientific Talk