Discovering the Extremes: CHEOPS and the Exoplanet WASP-189b
Written on
Chapter 1: CHEOPS and Its Extraordinary Find
The European Space Agency's (ESA) satellite CHEOPS is proving its capabilities by revealing one of the most astonishing exoplanets ever identified: WASP-189b. This gas giant, located over 322 light-years from Earth, orbits extremely close to its host star. It completes a full orbit in just three days and is 1.6 times the size of Jupiter, making it a prime example of an 'extreme' exoplanet.
"Artist's representation of CHEOPS observing WASP-189b, positioned between the planet's day side and its blue star. In reality, CHEOPS conducts its observations from Earth's orbit." © Frederik Peeters / David Ehrenreich
Section 1.1: The Significance of WASP-189b
The study concerning WASP-189b, which has been accepted for publication in Astronomy & Astrophysics, is significant as it underscores the potential of CHEOPS as the first mission specifically designed to study exoplanets in detail. Willy Benz, professor of astrophysics at the University of Bern and head of the CHEOPS consortium, expressed his enthusiasm for the mission’s initial findings.
Subsection 1.1.1: Characteristics of an Ultra-Hot Jupiter
WASP-189b is classified as a 'Hot Jupiter,' a type of gas giant that orbits very close to its star. These planets typically have short orbital periods of less than 10 days. Monika Lendl, the lead author of the study from the University of Geneva, notes that WASP-189b is particularly intriguing as it orbits 20 times closer to its star than Earth does to the Sun.
"Infographic detailing the WASP-189b system (ESA)."
Section 1.2: The Extreme Conditions of WASP-189b
The conditions on WASP-189b are severe, with one side of the planet always facing its star. Lendl states, “This planet has a permanent dayside, constantly exposed to stellar light, resulting in estimated temperatures around 3,200 degrees Celsius.” The planet orbits the extremely hot HD 133112 star, making it one of the hottest known exoplanets, where even iron would vaporize due to the high temperatures.
Chapter 2: Innovative Observational Techniques with CHEOPS
To study WASP-189b, astronomers utilizing CHEOPS employed innovative techniques due to the great distance of the HD 133112 system. CHEOPS measures a star's brightness to detect when an exoplanet transits in front of it, a method known as photometry.
"Highly precise brightness measurements of WASP-189b captured by CHEOPS: As the planet transits, the star appears dimmer for a brief period." (ESA)
During these observations, it was discovered that WASP-189b absorbs more starlight than it reflects, further raising its temperature. The absence of clouds on the planet's dayside is believed to contribute to this absorption.
The researchers also noted that the host star, HD 133112, differs significantly from our Sun. Benz explains that the transit of WASP-189b reveals asymmetrical brightness patterns on the star's surface, indicating rapid rotation and an ellipsoidal shape.
"An artist's impression of the CHEOPS telescope, part of ESA's first S-Class project aimed at identifying promising exoplanets for future study."
The extraordinary features of WASP-189b and its host star position this system as a target for future research. CHEOPS, developed through a collaboration involving over 100 engineers and scientists from eleven European nations, is fulfilling its mission to identify exoplanets and their systems for further exploration.