HD 80606 b
HD 80606 b
confirmed planet • updated: 2018-04-25
HD 80606 b orbits the star HD 80606, located about 66 light-years away. Scientists first spotted it in 2001 using the radial velocity method, which tracks tiny wobbles in the star’s motion caused by 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 slightly 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.
This planet is about 4.4 times the mass of Jupiter and 1.07 times its size. It orbits its star in about 111 days, but its path is extremely oval-shaped — one of the most eccentric orbits known for any planet. Because of this, it swings very close to its star at one end of its orbit and far away at the other. We don’t know its exact distance from the star or how much starlight it receives.
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 80606 b was first reported in 2001 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 111.44 days.
The orbit’s eccentricity is 0.93, which describes how stretched the orbit is. A higher eccentricity can imply stronger past interactions or migration, and it can matter for long‑term stability in multi‑planet systems.
The archive reports a mass scale of 4.4 MJ.
For radial‑velocity work this is commonly m·sin i (a minimum mass) because the orbital tilt is unknown. 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 80606 b orbits HD 80606.
A temperature near 5561 K places it on the sun-like side of the main sequence. The system is about 216.8 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: catalog equilibrium temperature, semi‑major axis. 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.