Elias 2-24 b: Youngest Known Planet

Why in News?

Astronomers have confirmed Elias 2-24 b as the youngest known planet.

Key Findings

• Location – The star lies in the ρ Ophiuchi star-forming region, a nearby stellar nursery.
• Size - The planet is roughly Jupiter-sized.
• It sits about 450 light-years from Earth and is still embedded in the gas and dust where it formed.  
• Age – Elias 2-24 b beats the earlier record holders, a four-way tie of worlds that are all more than 5 million years old.
• Those four are two planets around PDS 70 and two in the WISPIT 2 system.
• Host star – Earlier studies put the star at about 400,000 years old, and one suggested about 200,000 years.
• The authors therefore infer the planet is under a million years old, but assumed one million years to model its size.
• Distance from its star – The planet orbits roughly 55 times farther out than Earth does from the Sun.
• Mass – Most reports say it is about Jupiter's mass.
• The authors' modelling puts it at two to 14 times Jupiter, and the exact figure is uncertain because the planet is still growing inside a thick cloud of gas and dust.

Founding details

• Decade-old debate – Atacama Large Millimeter/submillimeter Array (ALMA) in Chile first revealed a gap in the disk around Elias 2-24.
• The European Southern Observatory's Very Large Telescope later spotted a light source within it.
• Astronomers argued for about 10 years over whether it was a planet.
• Archival Keck data – Bernardi's team re-examined Keck Observatory observations from 2018 and 2020 and found the object's motion matched a planet rather than a background star or imaging artifact.
• Coronagraph technique – A coronagraph blocks a star's glare so light from orbiting planets can be seen directly.
• The team searched coronagraph data for seven stars with debris disks, expecting a planet in a gap, and found one.
• Multi-telescope effort – Bernardi said the confirmation was possible only by using several telescopes together (ALMA, VLT and Keck).

Reference

Space | Youngest exoplanet on record — a 'newborn' named Elias