back in my day

On Friday night, Columbia Astronomy Outreach held their bi-monthly public lecture and stargazing series. Bwogger Mary Clare Greenlees went to find the answer to the old question, does size really matter? Moiya McTrier, a third year Ph.D. student, presented on whether or not size matters when using telescopes, and how it helps with her research on exoplanets.

To start off the talk Moiya McTrier made sure to tell the audience that she is an astronomer, not a telescope expert. There are many important people that are involved in maintaining and using telescopes, most of them aren’t astronomers! There are telescope operators, telescope engineers, and more! Most of them have backgrounds in engineering or computer science. What do the astronomers do then? If they aren’t the ones actually working on and maintaining telescopes? McTrier explains that most of her work involves coding. She sends the code to the telescope operator, who is then in charge of making sure that everything goes okay.

But how do astronomers choose their telescopes? McTrier made clear that size is not everything when deciding what telescopes to write proposals for. Angular resolution, the location, what you want to use the telescope for are all important factors in deciding what telescope astronomers want to use. However, McTrier said that there were two very important factors to consider, application cycle and instruments. Some of the bigger telescopes, such as Hubble are quite popular, and there is a rigorous application process to get time on the telescope. McTrier points out that some of the smaller telescopes can do as good of a job as the bigger ones.

McTrier centered most of her talk around the different types of instruments that are vital to astronomer’s research, with a special highlight on exoplanet research. Exoplanets are the name given to planets outside our solar system. Since the 1990s, we have discovered thousands of exoplanets! Currently, McTrier’s research studies whether or not the motion and structure of the Milky Way can affect exoplanet population.

Most exoplanets found were discovered using the transit method. The transit method measures the number of photons, using a photometer, emitted from a star. If nothing passes in front of the star, then the Luminosity will be constant. But, if a dip in light is seen, it’s probably going to be an exoplanet passing in front of its star. The best-known photometer is on Keplar, a retired satellite. However, this method only works in certain subsets, working best if there are large planets and if the small is smaller in comparison. (Fun fact: The Sun is not the most common type of star! Smaller stars are the norm in our Universe!)

However, an issue with the transit method is that we cannot find planets around stars who are close to us. But, we were able to find exoplanets around the closest star to us using radial velocity spectrometers. Throughout the lecture, McTrier made sure to engage the audience by having us raise our hands if we had heard something, and asked questions about what she was showing us. She asked the audience which star was closest to us. The little boy she called on was only happy to tell us that the Sun was the closest star to us. McTrier laughed and said he was correct! Though she did qualify that by saying that she would need to clarify the question, which got the answer she was looking for, Proxima Centauri. McTrier introduced herself to us not only as an astronomer, but as a science communicator that wanted to make science accessible to everyone. Science communication is a vital field and something that many scientists struggle in. McTrier made sure during her entire lecture that she was being understood, and that the material she was presenting was accessible for all backgrounds.

The final instrument McTrier explained was astrometric instruments, which measures the position and motion of stars. It’s able to track “wobble” of stars caused by planetary motion. The star rotates around the center of mass of its system, which can be affected by larger planets. This method is best for finding Jupiter size planets far from the star they orbit.

we lov recap slides !

All good things must come to an end, for now. Friday’s Astronomy Outreach event marked the last one of the Fall term, just as finals are right around the corner. The Columbia Astronomy Outreach lecture series has been a very successful way to communicate science to young kids, students, adults, and retired folk! The lecture and stargazing series is scheduled to start back up February 1st.



photos via Mary Clare Greenlees