An artist’s portrayal of a distant exoplanet resembling Jupiter. AF Lep b, which is approximately three times the mass of Jupiter, orbits AF Leporis, a youthful star similar to our Sun, situated about 87.5 light-years away.
In the realm of exoplanets, the discovery of over 5,000 of them has mostly been inferred. Astronomers primarily observe a slight dimming of a star’s light as a planet passes in front of it.
However, only a mere 15 planets orbiting other stars have been directly imaged.
Therefore, the recent imaging of a Jupiter-like planet circling a sun-like star in the constellation Lepus, approximately 87 light-years away, is a momentous event.
A Revolutionary Technique
Astronomers accomplished this feat by utilizing the Keck II telescope on Maunakea, Hawaiʻi Island. They captured an image of AF Lep b, one of the smallest planets ever detected through direct imaging, and discovered that its orbit closely resembles that of our own Jupiter in the solar system. AF Lep b boasts a mass about three times greater than Jupiter and revolves around a star named AF Leporis, which is a youthful star akin to our Sun.
This groundbreaking study was recently published in the Astrophysical Journal Letters. The researchers employed a fresh technique called astrometry, which involves meticulously measuring a host star’s subtle movements over several years to detect the gravitational pull exerted by orbiting planets.
This animation showcases the orbit of the extrasolar planet AF Lep b around its centered host star. The data was collected from December 2021 to February 2023 using the W. M. Keck Observatory in Hawaiʻi.
A Moving Target
The star AF Leporis was targeted due to its apparent movement during 25 years of observations from the Hipparcos and Gaia satellites. Remarkably, AF Lep b was detected despite being around 10,000 times fainter than its host star and positioned about eight times the Earth-Sun distance away.
“This marks the first instance of utilizing this method to identify a massive planet orbiting a young star analogous to our Sun,” stated Brendan Bowler, senior author of the study and assistant professor of astronomy at UT Austin. “The door is now open for utilizing this approach as a novel tool for discovering exoplanets.”
The Keck observatory and the Subaru telescope atop Mauna Kea in Hawaii, USA, captured during sunset.
Webb Telescope
This innovative technique holds the potential to aid astronomers in identifying and imaging low-mass exoplanets, exoplanets located at great distances from their stars, and exoplanets for which telescopes lack a direct edge-on view.
“The James Webb Space Telescope, along with the next generation of large ground-based telescopes like the Giant Magellan Telescope and the Thirty Meter Telescope,” Bowler mentioned, “will provide exceptional opportunities for further characterization of this planet. We already have plans for more sensitive follow-up investigations at longer wavelengths to study its physical properties and atmospheric chemistry.”
May your skies be clear and your observations astute.
