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Exoplanet · Neptune-like planet

TOI-3984 A b

TOI-3984 A b is a Neptune-like planet orbiting the star TOI-3984 A. Its year lasts 4.35 Earth days. It was discovered in 2023 by the Transit method.

Host starTOI-3984 A
Distance355.1 light-years (108.9 pc)
Orbital period4.35 days
Orbital radius0.041 AU
Eccentricity0.230
Radius7.9 R⊕ · 0.705 R♃
Mass44 M⊕ · 0.138 M♃
Density0.49 g/cm³
Surface gravity0.705 × Earth
Equilibrium temperature563 K (290 °C)
Stellar flux received16.7 × Earth
Discovery methodTransit
Discovery year2023
Discovered byTransiting Exoplanet Survey Satellite (TESS)

Habitable zone

Inside the inner edge of the habitable zone: it receives 16.7 times the light the Earth does, too hot to keep liquid water on its surface.

Its star in the sky

In the planet's sky its star is a disc 6.1° across: 11 times the Sun as we see it from Earth.

In the sky

A telescope is needed to see it: its apparent magnitude is 15.69. Visible from the whole Northern Hemisphere and south to latitude 53° S. North of latitude 53° N it never sets. It stands highest at midnight in May, the best time to observe it.

Light's journey

The light you see tonight set out around the year 1671. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 6.3 million years.

Open in the simulation

Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.