Thursday, April 20, 2023

Astronomers directly image massive exoplanet in radically new way only 132 light-years away in our Milky Way galaxy

Amazing stuff! We are not alone!

"For ages, astronomers have been intrigued by the notion of uncovering exoplanets – planets outside our Solar System. Thus far, astronomers have found over 5,300 of them with new discoveries coming in at an astounding rate. ...
The outcome was the discovery of HIP 99770 b, located some 132 light-years away. This planet is more than 15 times the mass of Jupiter and orbits a star almost twice as massive as the Sun. ..."

"In a breakthrough discovery, the Subaru Telescope’s powerful extreme adaptive optics system has imaged a massive benchmark gas giant planet around the nearby, bright star HIP 99770. The object, HIP 99770 b, is the first extrasolar planet jointly discovered by direct imaging and the new method of indirect detection, precision astrometry. This new approach for finding imageable planets simultaneously measures their mass, orbits, and even their atmosphere. It prefigures the way that we will someday identify and characterize an Earth twin around a nearby star. ..."

"Astrometry guides imaging detection
Direct imaging of exoplanets is challenging because of the glare of the much brighter host star. The technique has detected only small numbers of gas giant exoplanets on wide orbits. Astrometry, the precise measurements of stellar positions, could potentially identify stars being pulled by the gravity of a nearby planet. Currie et al. used astrometry to identify a candidate host star, which they then studied with direct imaging. They found an object with the right properties to explain the astrometry signal and interpreted it as an exoplanet of about 14 Jupiter masses. The detection shows how astrometry can help to detect and characterize directly imaged exoplanets."

From the abstract:
"Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures of planetary systems. However, few planets have been detected in blind surveys with direct imaging. Using astrometry from the Gaia and Hipparcos spacecraft, we identified dynamical evidence for a gas giant planet around the nearby star HIP 99770. We confirmed the detection of this planet with direct imaging using the Subaru Coronagraphic Extreme Adaptive Optics instrument. The planet, HIP 99770 b, orbits 17 astronomical units from its host star, receiving an amount of light similar to that reaching Jupiter. Its dynamical mass is 13.9 to 16.1 Jupiter masses. The planet-to-star mass ratio [(7 to 8) × 10−3] is similar to that of other directly imaged planets. The planet’s atmospheric spectrum indicates an older, less cloudy analog of the previously imaged exoplanets around HR 8799."

Astronomers directly image massive exoplanet in radically new way Star-mapping data and direct imaging could lead to even more exoplanet discoveries.

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