Nancy Thomas, Austin Gundy, & Moya Mapps

Research Goals

• The purpose of this research project was to compare the light curves of three variable stars from two different types, and overall, create a general understanding of them.

• Graph our light curves to show the change in brightness within a star over time.

• To complete these goals we will be using the 20 inch telescope along with the photometer. The numbers we record will allow us to make light curves and compare the stars.

Variable Stars Background• The two main divisions within

variable stars are:

– Extrinsic: The luminosity of the star changes because of external properties such as rotations or eclipses

– Intrinsic: The luminosity of the star changes because of physical changes in the star itself

Subdivisions

• Within these two divisions there are many subdivisions. We will be studying two pulsating intrinsic variables and one rotating extrinsic variable.

• The two intrinsic variables differ by another subdivision. One is an RR Lyrae type, and the other is a Cepheid. The two are similar, but the Cepheids are more luminous.

• In the rotating extrinsic variable, BY Draconis, sizable sunspots create differences in brightness as they rotate in and out of sight.

Our Proposed Stars

• Delta Cephei (SAO 34508)– Type: Intrinsic Cepheid Pulsating Variable– Magnitude: 3.5-4.4– Period: 5.36 days– Comparison Star: SAO 34227

• RR Lyrae (SAO 48421)– Type: Intrinsic RR Lyrae Pulsating Variable– Magnitude: 7.1-8.1– Period: 0.56 days– Comparison: SAO 48433

• BY Draconis (SAO 31048)– Type: Extrinsic Rotating Variable– Magnitude: 8.0-8.5– Period: 3.81– Comparison: SAO 31044

Our Actual Star

Selected Data Graph

Comparison Star Graph

Full Data Graph

Collecting and Reducing Data To gather actual data our group collected ten

photometer readings from the actual star, a piece of dark sky, and a comparison star. Thirty photometer readings gave us just one data point that you see in our graph.

To confirm that the star that we were studying was actually our star, we used a finder chart and a triangle of stars known as the “happy triangle.”

Factoring in Air Mass In addition, we also

had to account for air mass. To do this we measured the angle to the zenith (straight up) by subtracting the altitude from the zenith (90°)

To factor in air mass we multiplied our readings by the secant of the zenith angle (z).

Any Questions?

Uh-huh, those white puffy things in the sky.

On the night of June 24th, 2008, a group of very important people occupied the Jaimeson telescope on Mt. Lemmon. Little did these people know that the data they gathered would shake the foundations of science and research forever. Unaware of the weather conditions that preceded them, they attempted to gather photometry numbers on the specific star known as RR Lyrae. Unfortunately, yet, oh so fortunate, a layer of clouds began to roll over the mountain.

Naturally taken as an insult from nature, bad luck, bad karma, or just some scenario of the universe hating them, the astronomers cursed the clouds. However by some act of fate the photometer was still running. Disoriented by the presence of the clouds (as any normal astronomers would be) they began to take photometry numbers on the cloud surfaces.

The results were astounding, revealing some of the most concealed information in the universe. Several theories were instantly contradicted and the laws of physics were seriously doubted. The astronomers discovered the center of the universe, clarified the meaning of life, and finally established a unified Theory of Everything. As the data streamed into the computer, the several astronomers witnessing it rushed into action.

They rushed the data to the nearest TV broadcasting station and, by force, overtook the facility. They then entered the data in the form of this very Powerpoint and put it over world wide television on every channel, but unfortunately, absolutely nobody was watching. The astronomers then decided that these new discoveries were simply too astounding for the new found universe to allow to be distributed freely.

A couple of nights later, the same group of astronomers went back to the same telescope to see if they could observe the same information, and perhaps, gather even more data than possibly imaginable. However, they were astounded to find that when they gathered data on the clouds in the new night sky, they found…

Clouds. There was nothing special about these clouds, they were just clouds. No useful information could be gathered. A closer look at the database, and the astronomers found that all of the incredible data they had gathered in the nights before, was gone, and had no evidence of the findings they have concluded. It seems that the universe had erased the data and provided no evidence of the phenomenon.

Alas, the data we came out with once represented the greatest discovery in the history of the universe. But now, it strictly represents clouds.

So you guys can see it.

Data Gathered June 24th

…More Cloud Data June 30th

The Results…

Conclusion Clouds block stars. Clouds rain. Clouds hate astronomers. Astronomers hate clouds. Clouds are in the sky. It was getting cloudier.

Thank you all

Bye-bye.