Over 5000 candidate exoplanet candidates and over 200 confirmed exoplanets have been found by NASA's transiting exoplanet survey satellite. TESS is good at finding exoplanets, but it is also good at making other discoveries. Scientists working with TESS recently announced 97 quadruple star candidates, nearly doubling the number of known quadruple systems.
TESS wants to find exoplanets. It's mission is to find exoplanets around bright stars. The transiting exoplanet survey satellite can study the planets.
The field of view of TESS is much larger than that of the Kepler Space Telescope. Its wide-field cameras have surveyed 85% of the sky and gathered an enormous amount of data. Scientists use machine learning to comb through the data.
According to a new paper, the latest results from TESS data are a catalogue of 97 candidates for quadruple star systems. The paper is titled "97 Eclipsing Quadruple Star Candidates Discovered in TESS Full Frame Images" and will be published in The Astrophysical Journal Supplement. The paper's lead author is a NASA scientist.
The candidates were identified in TESS Full Frame Image data from Sectors 1 through 42 through a combination of machine learning techniques and visual examination, with major contributions from a dedicated group of citizen scientists.
It took a collaboration between some of the usual suspects to find these systems. The professionals at those institutions needed some help. The help came from seven citizen scientists who helped with the analysis of light curves.
The results go beyond the multiple star systems that the researchers focused on. The first sextuply-eclipsing sextuple stellar system and the first transiting circumbinary planet were detected from one sector of TESS data.
There are two pairs of stars in a quadruple star system. If they eclipse one another from our point of view, they are only EBs. The helping hand from citizen scientists is due to the difficulty in entangleing transits and eclipses.
The targets listed in this catalogue are quadruple candidates that each originate from a single TESS source. The quad systems are in the catalog because they exhibit changes observable in human timescales.
It's a bit wordy, but the main point is that TESS can be vast. If TESS locates a pair of EBs separated by two TESS pixels, and if the EBs are 500 parsecs away from us, that means the EBs are separated from each other by up to 20,000AU. It could take generations of human observations to notice any interactions between the stars. The systems have to be close to each other to have interesting interactions observable in months or years. This is the reason for the analysis.
The systems were subjected to a vetting process. Many false positives were encountered by the team. A field star near the target was often thought to be another one. Sometimes they found two pairs, but they were too far away from each other to be considered a quadruple star system. There were triple star systems that had the same eclipse pattern as a quadruple star system. There were five false-positive scenarios.
The target stars have been identified through visual inspection and exhibit two sets of eclipses with two distinct periods, each with a primary and a secondary eclipse. All targets have been uniformly-vetted and passed a series of tests.
The photocenter has motion analysis.
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