HU Aqr AB b
HU Aqr AB b
derived planet • updated: 2019-10-18
HU Aqr AB b orbits the binary star system HU Aqr. Scientists found it by watching how the timing of eclipses between the two stars changed — a method called eclipse timing variations.
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 an estimated mass of about 5.9 times that of Jupiter and orbits at a distance of roughly 3.6 times Earth’s distance from the Sun. Its orbit is thought to be circular. Because it was found using eclipse timing, the mass estimate depends on assumptions about the system’s geometry, and the catalog flags this discovery as controversial.
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.
HU Aqr AB b was first reported in 2011 using the Eclipse Timing Variations method.
The discovery is linked to observations from Yunnan Astronomical Observatory. Different methods emphasize different strengths: some constrain size, some constrain mass, and some constrain both.
The catalog lists an orbital period of about 2390.00 days, a semi-major axis near 3.600 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 5.9 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
HU Aqr AB b orbits HU Aqr.
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.