By: Zoe T.
School: Laguna Beach High
Science Teacher: Jennifer Park
In the world of astronomy, the discovery of exoplanets has opened up new frontiers in our understanding of the universe. However, the accuracy of identifying exoplanets using transit photometry has been hindered by false positives, leading to the need for more effective analysis methods. Zoe, a talented 9th grader, has taken up this challenge and developed an innovative approach to address the limitations of current techniques. Her project, showcased at the OCSEF, introduces a novel criterion called the light curve delta ratio (LDR) and the Z-factor, which significantly enhance the accuracy and specificity of exoplanet identification.
Zoe recognized that commonly employed methods, such as light curve analysis, determination of an object’s radius, and its Renormalized Unit Weight Error (RUWE), have subjective elements and limited effectiveness. To overcome these challenges, she formulated a method to quantify the data from light curves by analyzing the changing slope of the curve, leading to the development of the LDR. By combining the LDR with RUWE and the radius of the exoplanet candidate, Zoe derived a mathematical equation that yielded a new value: the Z-factor. This equation and the subsequent Z-factor provide a more accurate means of identifying exoplanets within large transit datasets.
To validate her approach, Zoe employed a dataset comprising confirmed exoplanets and non-exoplanets. Through meticulous analysis, she determined that an LDR threshold limit greater than 2.00 and a Z-factor threshold greater than 1.00 were indicative of exoplanets. Remarkably, the LDR alone exhibited a sensitivity and specificity of 92.31% and 84.62%, respectively. However, the Z-factor outperformed all other factors, showcasing a sensitivity, specificity, and accuracy of 100%. Additionally, the Z-factor successfully reduced the number of TESS (Transiting Exoplanet Survey Satellite) objects of interest from 50 to 36, resulting in a 28% reduction. This compelling outcome demonstrates the usefulness of the Z-factor as a valuable screening tool for large transit datasets.
Based on her research findings, Zoe draws several noteworthy conclusions. Firstly, she emphasizes that the LDR, as an objective and quantitative method, significantly enhances the analysis of light curve data with high sensitivity and specificity. Furthermore, the Z-factor, with its exceptional accuracy of 100%, proves to be an effective means of narrowing down exoplanet candidates from vast datasets. Zoe’s results firmly support her initial hypothesis that combining the LDR with other factors, such as RUWE and the exoplanet candidate’s radius, would increase the accuracy of exoplanet determination.
Looking to the future, Zoe intends to refine her formulas by expanding the number of test cases for the LDR and Z-factor. She also contemplates assigning different weights to the variables in the equation to further optimize its performance. Moreover, Zoe aims to apply her method to larger subsets of exoplanet candidates, seeking additional validation of its accuracy.