Astronomers confirm youngest known planet, a baby Jupiter still forming

Overview

Updated Sep 17

Astronomers have confirmed a planet less than a million years old, the youngest ever found. Elias 2-24 b is a Jupiter-size world still gathering gas from the disk of dust around its host star, 450 light-years from Earth.

The discovery challenges planet formation models, which predict building a Jupiter-size planet takes about 5 million years even at Jupiter's distance, and longer farther out. Elias 2-24 b sits 55 times farther from its star than Earth is from the Sun.

Why it matters

If giant planets can form in under a million years, the timeline for how planetary systems—including our own—take shape needs rewriting.

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Key Indicators

<1 million years

Age of Elias 2-24 b

Youngest known planet, still actively forming.

1.9–4.0 M_Jup

Estimated mass

Comparable to Jupiter, inferred from photometry and 1-million-year isochrones.

55 AU

Distance from host star

55 times the Earth-Sun distance, far beyond where models predict rapid formation.

450 light-years

Distance from Earth

Location of the Elias 2-24 system in the constellation Taurus.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Andrea Bernardi

Doctoral student at Diego Portales University, lead author of the confirmation study

Lead author of the study confirming Elias 2-24 b

Lucas Cieza

Astronomer at Diego Portales University, co-author of the study

Co-author of the study confirming Elias 2-24 b

Organizations Involved

Diego Portales University

University

Lead research institution for the Elias 2-24 b confirmation

Private university in Santiago, Chile, where the study's lead author works.

W. M. Keck Observatory

Observatory

Provided archival data used to confirm Elias 2-24 b

Twin 10-meter telescopes on Maunakea, Hawai'i, among the largest optical telescopes in the world.

National Aeronautics and Space Administration (NASA)

Federal space agency

Funded the Keck Observatory Archive; operates the Nancy Grace Roman Space Telescope

United States space agency that funded the archive used to confirm Elias 2-24 b.

ALMA – Citizens for Cyprus

Observatory

First observed the gap in Elias 2-24's disk

Radio telescope array in Chile that first revealed the gap in Elias 2-24's dusty disk.

European Southern Observatory

Intergovernmental research organization

Operated the Very Large Telescope that detected the candidate planet

European intergovernmental astronomy organization operating the Very Large Telescope in Chile.

Timeline

2016 September 2026

6 events Latest: September 17th, 2026 · 2 months ago

Tap a bar to jump to that date

September 2026
Elias 2-24 b confirmed as youngest known planet
Latest Publication

Study confirms Elias 2-24 b as the youngest known planet, less than a million years old.
September 17th, 2026
August 2026
Roman Space Telescope launches
Launch

NASA's Nancy Grace Roman Space Telescope launches with a more powerful coronagraph for detecting young planets.
August 30th, 2026
2020
Additional Keck observations recorded
Observation

More Keck archival observations of Elias 2-24 are recorded, later used to confirm the planet's motion.
2020
May 2018
Keck coronagraph observes Elias 2-24
Observation

Keck/NIRC2 vortex coronagraph observations capture the candidate planet in the L' and Ms bands.
May 2018
2017
VLT spots faint point of light in gap
Observation

VLT detects a faint point of light in the gap, later identified as a candidate planet.
2017
2016
ALMA reveals gap in Elias 2-24's disk
Observation

ALMA observations reveal a gap in the young star's dusty disk, a possible sign of planet formation.
2016

Scenarios

Roman telescope confirms more baby planets

Likely Resolves by End of 2028

Discussed by: NASA, study authors including Andrea Bernardi and Lucas Cieza

The Nancy Grace Roman Space Telescope, launched Aug 30, 2026, carries a more powerful coronagraph than current instruments. If it detects more young planets in protoplanetary disks, the rapid formation scenario gets validated and Eliass 2-24 b becomes the first of a new class of observed objects.

Planet formation models revised

Possible Resolves by Q2 2028

Discussed by: Planet formation theorists, study authors

If Elias 2-24 b's rapid formation is confirmed as typical, the core accretion model may need to account for faster gas accumulation at wide separations. A revised model would update the predicted timescales for giant planet formation.

Alternative formation mechanism proposed

Possible Resolves by End of 2027

Discussed by: Planet formation theorists

Some astronomers may argue the planet formed via disk instability rather than core accretion, since core accretion struggles to explain such rapid formation at wide separations. A competing paper would lay out the alternative mechanism.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

2018

PDS 70 b (2018)

Astronomers using the Very Large Telescope confirmed PDS 70 b, a gas giant still forming within the disk of its young star, 370 light-years away. It was the first unambiguous detection of a planet still accreting material from its natal disk.

Then

Confirmed that planets can be directly imaged while still forming.

Now

Opened the door for studying planet formation in real time.

Why this matters now

Like Elias 2-24 b, PDS 70 b was caught in the act of formation, but PDS 70 b is older and closer to its star.

1995

51 Pegasi b (1995)

Michel Mayor and Didier Queloz discovered a Jupiter-size planet orbiting 51 Pegasi in just 4.2 days. The existence of a hot Jupiter so close to its star contradicted planet formation models of the time.

Then

Sparked a revolution in exoplanet science.

Now

Led to the discovery of thousands of exoplanets and the realization that planetary systems are far more diverse than predicted.

Why this matters now

Like Elias 2-24 b, 51 Pegasi b challenged the prevailing models of how planets form.

2008

HR 8799 (2008)

Christian Marois and colleagues directly imaged three planets orbiting HR 8799 using the Keck and Gemini telescopes. The planets were massive and far from their star, challenging formation models.

Then

Demonstrated that direct imaging could find planets.

Now

Showed that massive planets can exist at wide separations, raising questions about formation mechanisms.

Why this matters now

Elias 2-24 b is also a massive planet at a wide separation, and its confirmation relied on Keck data, just like HR 8799.