HIP 81208 C b
HIP 81208 C b
confirmed planet • updated: 2023-07-25
HIP 81208 C b orbits the star HIP 81208 C, a small, cool red star. Scientists found it using direct imaging — taking a picture of the planet itself — from the Paranal Observatory in 2023.
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 object has a mass about 14.8 times that of Jupiter, placing it near the boundary between giant planets and brown dwarfs. It orbits its star at about 23 times Earth’s distance from the Sun, taking over 280 years to complete one orbit. Its estimated temperature is around 2050 Kelvin — very hot, likely due to internal heat rather than starlight.
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.
HIP 81208 C b was first reported in 2023 using the Imaging method. The discovery is linked to observations from Paranal Observatory.
Direct imaging tries to separate faint planetary light from the glare of the host star. It works best for young, warm planets far from their stars.
The catalog lists an orbital period of about 104100.00 days, a semi-major axis near 23.040 AU.
Eccentricity is not provided here; many catalogs omit it when the solution is underconstrained.
The archive reports a mass scale of 14.8 MJ.
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
HIP 81208 C b orbits HIP 81208 C.
The star is classified as M, which is a shorthand for temperature and color. The system is about 481.2 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, eccentricity. 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.