HD 63433 b
HD 63433 b
confirmed planet • updated: 2024-07-23
HD 63433 b circles the star HD 63433, which is slightly smaller and cooler than our Sun. Scientists found it when the planet passed in front of its star, causing a tiny dip in starlight — a method called transit.
This page summarizes what’s been measured and published. If a value is missing, it’s not shown or guessed. Some numbers vary slightly between studies; when that happens, we describe the range rather than pick one without evidence.
Scientific context
Scientific context: This profile layers interpretation on top of archival measurements. Modeled bands appear where direct detections (like spectra or transits) are not listed.
What we can’t claim: surface conditions, biology, or breathable atmosphere without direct spectra.
HD 63433 b is a planet about 2.16 times Earth’s size and 37 times Earth’s mass — making it a ‘sub-Neptune’ or ‘mini-Neptune’ type world. It orbits very close to its star, completing a full trip in just over 7 days. Its surface temperature is estimated at around 886 Kelvin (about 613°C or 1135°F). The planet’s orbit may be nearly circular, but some studies suggest it could be slightly oval-shaped — we don’t yet have a precise measurement for that.
Glossary (plain English)
- AU: the average Earth–Sun distance.
- Semi-major axis: the planet’s average distance from its star.
- Eccentricity: how oval the orbit is (0 = circle).
- Radial velocity: finding a planet by measuring a star’s tiny “wobble.”
- m·sin i: a minimum mass estimate; the true mass can be higher if the orbit is tilted.
- Equilibrium temperature: a rough estimate from starlight alone, not a surface reading.
HD 63433 b was first reported in 2020 using the Transit method. The discovery is linked to observations from Transiting Exoplanet Survey Satellite (TESS).
In transit work, astronomers watch for tiny, repeating dips in a star’s light as the planet passes in front of it. Follow-up observations help rule out false positives and refine the orbit.
The catalog lists an orbital period of about 7.11 days, a semi-major axis near 0.072 AU.
The orbit’s eccentricity is 0.00, which describes how stretched the orbit is. Because this is a multi‑planet system, stability is ultimately tested with dynamical (N‑body) fits; catalogs can update as models improve.
The archive reports a mass scale of 0.1 MJ.
A catalog radius is also listed, which (together with mass) helps constrain density and interior structure.
Why “m·sin i” shows up on RV planets
HD 63433 b orbits HD 63433.
A temperature near 5634 K places it on the sun-like side of the main sequence. The system is about 73.1 light‑years away.
Several key parameters are not present in this single catalog row.
Missing fields don’t mean the science is unknown—only that this particular snapshot doesn’t carry the values. As new observations arrive, archives often refresh these entries (and sometimes revise earlier numbers).
Scientists keep revisiting systems like this because each new instrument pass can tighten uncertainties: better timing improves the orbit, better spectra improves the star, and better follow‑up can confirm or refute competing solutions. Even when a planet is well‑established, refined stellar properties can shift the inferred planet size, temperature, and habitability context. Transit systems are especially valuable because they can be re‑observed for decades to detect subtle changes in timing or additional planets.