Elias 2-24 b: Youngest Known Planet Confirmed
Why in News?
Astronomers have confirmed Elias 2-24 b, a Jupiter-mass exoplanet estimated to be less than 1 million years old. It is currently the youngest known planet, offering scientists a rare opportunity to observe a giant planet while it is still forming. The planet orbits the young star Elias 2-24, located about 450 light-years from Earth. Unlike most known exoplanets, it remains embedded in the protoplanetary disk of gas and dust from which it formed.
Discovery of Elias 2-24 b
The presence of a possible planet was first suggested by a prominent gap in the protoplanetary disk observed around Elias 2-24. Earlier observations by ALMA revealed the disk structure, while the European Southern Observatory’s Very Large Telescope (VLT) detected a faint source within the gap. However, scientists needed additional evidence to confirm that the source was actually a planet.
A team led by Andrea Bernardi, a doctoral candidate at Universidad Diego Portales in Chile, examined archival observations from the W. M. Keck Observatory. Data from 2018 and 2020, combined with newer observations, showed that the object moved consistently with a planet orbiting Elias 2-24 rather than being a background star or an imaging artifact.
Planet Formation and Accretion
Elias 2-24 b has a mass approximately comparable to Jupiter. It is located about 55 times farther from its host star than Earth is from the Sun. The planet is still actively accreting material from the surrounding disk. This provides direct observational evidence of an important stage in giant-planet formation. The discovery supports the core-accretion model, in which a planetary core grows by accumulating solid material and subsequently gathers large quantities of gas from the surrounding disk.
Protoplanetary Disks and Planet Formation
A protoplanetary disk is a rotating disk of gas, dust, ice and rocky material surrounding a young star. Planets form from this material through processes of accumulation and gravitational growth. Gaps in these disks can be created or shaped by growing planets. Elias 2-24 b is particularly important because it has been detected inside such a gap while the planet itself is still forming.
The discovery may therefore help scientists improve models of giant-planet formation. Existing models had difficulty explaining how Jupiter-sized planets could form so quickly, particularly at large distances from their host stars.
Telescopes Used in the Discovery
The confirmation involved observations from several major astronomical facilities:
- W. M. Keck Observatory, Hawaii — archival high-contrast imaging and coronagraph observations.
- Atacama Large Millimeter/submillimeter Array (ALMA), Chile — observations of the protoplanetary disk.
- European Southern Observatory’s Very Large Telescope (VLT), Chile — detection of the faint source within the disk gap.
A coronagraph is particularly useful for such observations because it blocks the intense light of a star, allowing much fainter objects near it to be detected.
Elias 2-24 b: Important Facts for Exams
| Feature | Details |
|---|---|
| Planet | Elias 2-24 b |
| Type | Young giant exoplanet |
| Estimated age | Less than 1 million years |
| Mass | Approximately Jupiter-mass |
| Host star | Elias 2-24 |
| Distance from Earth | About 450 light-years |
| Location | Within a gap in the protoplanetary disk |
| Formation stage | Still actively accreting material |
| Lead researcher | Andrea Bernardi |
| Institution | Universidad Diego Portales, Chile |
| Major facilities | Keck, ALMA and ESO VLT |
| Study | Published in The Astrophysical Journal Letters |
| Significance | Youngest known planet and a rare view of active planet formation |
