Unistellar Exoplanet Campaign – A New Citizen Science Program

By Michael Horton •  Updated: 09/19/22 •  4 min read

Amateur astronomers are invited to confirm exoplanet candidates using either Unistellar’s eVscope or another telescope, the SETI Institute and its partner Unistellar have announced. While looking for potential exoplanet transits from Earth, NASA’s Transiting Exoplanet Survey Satellite (TESS) previously detected the planets.

The transit method has been used to find the majority of known exoplanets, most notably by the Kepler Mission and currently by TESS. A transit occurs when a planet passes in front of its star, causing the star to fade as the viewer watches.

More than ever, there is a need for additional observations of transiting exoplanets. With thousands more detections to be confirmed, there are presently over 5,100 confirmed exoplanets. Exo-Jupiters found by those NASA missions will be the program’s primary focus.

10,000 Exoplanet Candidates?

multiple planet system

Artist’s conception of a multiple planet system. Credit: Gemini Observatory. Artwork by Lynette Cook

According to some projections, TESS will find more than 10,000 candidates for exoplanets. Unconfirmed exoplanets require additional observations to verify whether they are false positives brought on by eclipsing binaries or low-mass star transits, for example.

For confirmed planets, periodic re-observations by ground-based systems are required to maintain the accuracy of their orbital ephemerides. The potential for citizen scientists to further our understanding of exoplanets is great, and this has fascinating ramifications for STEM education.

Non-professional astronomers have mostly been excluded from opportunities to observe and contribute their obtained data to exoplanet research or education. Obstacles include the expensive expense of running, creating, or using observing equipment, as well as the high degree of technical skill necessary.

Exoplanet Candidate TOI 1812.01

Professional mentoring and carefully selected targets are offered by the Unistellar Exoplanet Campaign. It can involve non-professionals and students in this exciting endeavour while making significant contributions to exoplanet research (for example, photometric data for tracking transit times and confirming traditional and long-period exoplanets).

The discovery of the TESS planet candidate TOI 1812.01 is one of the newest accomplishments of the new network. TESS made the initial discovery of the strange multi-planet system known as TOI 1812.

A 3-Earth-radius sub-Neptune planet on an 11-day orbit, a 5-Earth-radius sub-Saturn planet on a 43-day orbit, and an outer 9-Earth-radius Saturn-sized planet (TOI 1812.01) on what was once an unconstrained orbit, make up this star system, which is 563 light-years from Earth.

TOI 1812 is the perfect system to study the formation and migration of big planets because it has three gaseous planets with a wide range of radii. Furthermore, TOI 1812.01 receives insolation less than twice that of the Earth and may potentially be a fascinating target for future exomoon searches because of the cold temperature of the K2V host star.

Unknown Orbital Period

The orbital period of TOI 1812.01, which is unknown, is the puzzle piece that prevents further definition. A collection of aliases was left as the potential orbital period after TESS recorded two transits of this planet lasting eight hours that were separated by a sizable data gap.

The three most likely orbital periods were identified by statistical analysis of sparse radial velocity data as being 71 days, 87 days, or 112 days.

These three scenarios matched up with three potential travel windows in July and August 2022. The network kept track of each window, which in each case needed cross-country operations. It received 27 data sets over the three periods from 20 astronomers in 7 different nations.

For the first two periods, the network effectively ruled out transits. It confirmed the orbital duration of 112 days when it found the transit egress (ending) during the third window on August 27, 2022.

The Effectiveness Of Citizen Science

This project demonstrates how the citizen science network may specifically help with the recovery of orbital ephemerides of exceptionally valuable long-period and long-transit-duration exoplanets, such TOI 1812.01. This research, which includes the Unistellar observations, is being prepared for a report that will be presented at the International Astronautical Congress in Paris on Tuesday, September 20, in order to formally establish the planetary system’s identity.

“Observing exoplanets like TOI 1812.01 as they cross in front of, or transit, their host stars is a crucial component of confirming their nature as genuine planets and ensuring our ability to study those planetary systems in the future. The specific properties of this planet, namely its long orbit and long transit duration, put it in a category where citizen science coordinated on a global level like the Unistellar Network can be extremely effective,”

said Paul Dalba, SETI Institute research scientist.

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