HIP 99770 b
HIP 99770 b
confirmed planet • updated: 2023-04-17
HIP 99770 b was spotted using direct imaging — meaning astronomers took a picture of it next to its star. It orbits far out, taking about 51 years to complete one trip around its host.
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 16 times that of Jupiter, placing it near the boundary between planets and brown dwarfs. It orbits its star at about 17 times Earth’s distance from the Sun, on a slightly oval path. Because it was imaged directly, we know its position and brightness, but not its size or surface temperature.
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 99770 b was first reported in 2023 using the Imaging method. The discovery is linked to observations from Multiple Observatories.
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 18600.00 days, a semi-major axis near 16.900 AU.
The orbit’s eccentricity is 0.25, which describes how stretched the orbit is.
The archive reports a mass scale of 16.1 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 99770 b orbits HIP 99770. The star is classified as A5-A6, which is a shorthand for temperature and color.
A temperature near 8000 K places it on the hotter side of the main sequence. The system is about 130.7 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.