Excerise
Study the GIFs below of different comets to answer the questions in the lab manual.
- Describe the orientation of the comets’ tails with respect to the comets’ motion.
- Do you observe something strange in these GIFs? What is it? Suggest a hypothesis to explain what you observe.
Comet ISON
In November 2013, Comet ISON approached the Earth on its way to the Sun. On the background section of this lab, you will find an image from SOHO of its approach to the Sun. Using the telescope Iowa Robotic Observatory’s telescope Rigel, students at the University of Iowa took images of ISON. Download the images and open them in Maxim DL to answer the following questions.
ISON1.fts
ISON2.fts
ISON3.fts
- Using Maxim, animate the three images of Comet ISON. You can find a tutorial on how to animate images here.
(a) Using the coorinate grid provided in the lab manual, plot the position of the comet and its tail orientations for one of the images provided. The FITS header window (crt+f) will have the RA and dec of the comet.
(b) Using your hypothesis from question 2, plot another relevant celestial object on the coordinate gride at the date of observation for one of the images provided. What is the orientatio of the comet’s motion and tail direction with respect to this object?
Background
Comets are essentially “dirty snowballs”, meaning they are made of ice and dirt. Many of the discovered comets originated in the Oort cloud. In the outer Solar System, comets do not have tails or comas but are compact objects that are difficult to observe.
As a comet travels through the Solar System and becomes closer to the Sun, sunlight will start to heat the surface of the comet, leading to the formation of both the tail and the coma. During this time, it is easier to observe comets, as they will become bright due to the dirt being released from the surface and the ice reflecting sunlight.