Planet That Turns the Rules Inside Out

A team of scientists used the CHEOPS telescope to observe a distant star, LHS 1903, located roughly 117 light‑years away. This faint red dwarf, half the mass of our Sun, hosts four planets that challenge conventional planetary formation models.

The Unusual Order of Worlds

• Inner rocky planet – a super‑Earth.
• Two mini‑Neptunes – gaseous worlds smaller than Neptune but larger than Earth.
• Outer rocky planet – another super‑Earth, surprisingly far from the star.

This arrangement contradicts the typical expectation that outer planets are gas‑rich, forming in colder regions with more available gas.

Why the Anomaly?

Scientists propose two scenarios:

1. Sequential Formation – Planets formed one after another; the last planet accreted little gas.
2. Atmospheric Loss – The outer rocky planet may have once possessed a thick atmosphere but shed it—possibly due to a massive collision.

The Outer Rocky World

• Mass: ~5.8 × Earth
• Surface Temperature: ≈ 60 °C (≈ 140 °F), comparable to Earth’s hottest location.
• Potential: A prime target for studying habitability and the limits of life beyond our planet.

Looking Ahead

Future observations with the James Webb Space Telescope could reveal atmospheric details and assess whether this world can support life.