Two Approaches to the Search for Life: Comparison Study of Titan Haze Analogs and Coronagraph Mask Designs for Exoplanet Imager
Physical and Biological Sciences
Phys 195A/B and Phys 199 (Independent Studies)
With the data collected and analyzed from missions like Kepler, we now know that on average, there's at least one planet orbiting each star in the universe. From past and current surveys, "Super-Earths" (planets between 0.5 and 2.5 earth radii) occur the most. Although the frequency of such planets inside the habitable zone of the star(s) they orbit remains unknown, we can proceed to answer the next big question of "Are we alone in the universe?". In this work, I have detailed two separate approaches to the question.
My first approach involves laboratory experiments that will help us better understand the current bodies in our solar system, more specifically the properties of atmospheric molecules. The atmosphere of Titan, a moon of Saturn, is composed of mainly nitrogen and methane and is full of organic haze particles. Such haze particles have been found to be similar to haze in early Earth's air -- haze that may have helped nourish life. As we currently do not have a sample of Titan’s haze, the analogs of hazes, called Tholins, are produced in various laboratories on Earth. My co-authors and I have performed a surface energy comparison study on analogs of hazes on Titan. We identified a commonality between different tholin samples from different laboratories, which can be an indication that actual Titan hazes might possess the same characteristic. Thus, it can have implications and insights into the current processes of Titan and allow us to better understand the chemical interactions that occurred before life developed on Earth.
My second approach advances the technology of instrumentation for direct imaging of exoplanets, or planets orbiting other stars, by blocking the lights from the star to directly see the light from the planet(Here you may want to say exactly what is direct imaging before going to the analogy), Directly imaging distant exoplanets is a strenuous task that has been described as analogous to “finding the firefly flitting next to the lighthouse.” The light from these exoplanets is obscured by the overwhelming light from the star they orbit, making them difficult to image. However, directly imaged exoplanets are typically more robust detections and can provide vital information to their atmospheric composition, which is essential to determine habitability. To eliminate the blinding starlight, astronomers use coronagraphs, a common technique that involves placing masks within or in front of the telescope to cover the star. My work focuses on the designs of a compartment for a future direct imaging instrument for the Keck II Telescope, Santa Cruz Array of Lenslets for Exoplanet Spectroscopy (SCALES). I have optimized the mask by simulating the throughput with various instabilities under different realistic scenarios to maximize their performance inside SCALES. By further reducing the noise in future projects, we can increase the possibility of finding direct-imaged exoplanets with the next-generation instrumentation.
