HD 66428 c
HD 66428 c
confirmed planet • updated: 2023-06-12
HD 66428 c orbits the star HD 66428. Scientists found it using the radial velocity method, which tracks how the star moves slightly due to the planet’s gravity.
This page summarizes a catalog entry. If a measurement is missing, it is not shown or guessed. Some values can differ between studies; when that happens, we describe the range rather than picking a favorite 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.
The planet has a very long orbit — about 10,500 days (roughly 29 years) — and a very high mass, at least 560 times Earth’s mass (or about 1.8 times Jupiter’s mass). Because radial velocity gives a minimum mass, the true mass could be higher if the orbit is tilted. The orbit is slightly oval-shaped, not perfectly circular.
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 66428 c was first reported in 2021 using the Radial Velocity method. The discovery is linked to observations from Multiple Observatories.
Radial-velocity detections come from subtle shifts in the star’s spectrum as it wobbles under the planet’s gravity. The first mass value is often a minimum (m·sin i) unless the orbit’s tilt is known.
The catalog lists an orbital period of about 10478.84 days, a semi-major axis near 9.408 AU.
The orbit’s eccentricity is 0.21, 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 1.8 MJ.
For radial‑velocity work this is commonly m·sin i (a minimum mass) because the orbital tilt is unknown. A rough radius estimate is shown for UI completeness, but it should not be treated as a measurement.
Why “m·sin i” shows up on RV planets
HD 66428 c orbits HD 66428.
The system is about 173.8 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.
In this case the most noticeable gaps are: radius, catalog equilibrium temperature. 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.