Imma Perfetto
Cosmos science journalist
The SETI Institute and its partner Unistellar have launched a new exoplanet detection program for citizen scientists worldwide.
Known as the “Unistellar Exoplanet Campaign” amateur astronomers will be able to help confirm exoplanets – a planet that orbits a star outside the solar system – identified by NASA’s Transiting Exoplanet Survey Satellite (TESS).
They’ll do this by observing possible exoplanet transits which occur when a planet passes between its star and the observer, resulting in a temporary dimming of the star which can be recorded by ground based telescopes. Most known exoplanets have been detected using the transit method.
There are more than 5,100 confirmed exoplanets. With thousands more detections that still need to be confirmed, and some estimates suggesting that TESS will identify more than 10,000 exoplanet candidates, the demand for follow-up observations is greater than ever.
These are essential to determine whether unconfirmed exoplanet candidates are potentially “false positives” because a drop in brightness of a star over a period of time may also be caused by another object passing in front of it.
For instance, in an eclipsing binary system where two stars orbit each other, the light of the one can sometimes be hidden behind the other.
It’s also necessary to re-observe confirmed exoplanets using ground-based systems so their “orbital ephemerides” – their trajectory in the sky over time – can remain updated.
This is where citizen scientists come into the picture.
Observing three gaseous exoplanets
The campaign will provide professional mentoring and curated targets focusing on exo-Jupiters specifically – gas giant planets that are physically similar to Jupiter.
One of the network’s most recent achievements is the detection of the exoplanet candidate TOI 1812.01. It comes from a multi-planet system 563 lightyears from Earth that consists of three gaseous planets: a 3-Earth radii planet on an 11-day orbit; a 5-Earth radii on a 43-day orbit; and an outer 9-Earth radii planet (TOI 1812.01) on what was previously an unknown orbit.
Over three possible transit windows in July and August 2022, 27 data sets were contributed to the project by 20 amateur astronomers across seven countries. With this they were able to confirm TOI 1812.01 has an orbital period of 112 days.
This work, including the Unistellar observations, is being prepared for a manuscript to officially confirm the nature of the planetary system and will be presented at the International Astronautical Congress (IAC) in Paris, France.
“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,” says Dr Paul Dalba, SETI Institute research scientist. “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.”
“This early success shows the power of putting science directly into people’s hands; a core principle of this SETI Institute, Unistellar, and NASA partnership,” adds Dr Tom Esposito, SETI Institute research assistant and Space Science Principal at Unistellar. “Citizen astronomers worldwide, uniting to teach humanity about new planets discovered so many trillions of miles away, is, simply put, amazing.”
Observation targets will be regularly announced here.
Other citizen science programs are available through the Unistellar Network if you’re more interested in detecting near-Earth objects for planetary defence or detecting asteroids flying in front of distant stars.