HIP 97166 b

HIP 97166 b — Exoplanet profile
Exoplanet profile

HIP 97166 b

Host star: HIP 97166 • Discovery: 2021 • Method: Transit
confirmed planet • updated: 2024-07-23
confirmed planet transit modeled atmosphere derived

HIP 97166 b orbits the star HIP 97166, located about 66 light-years away. Scientists found it using the transit method — watching for tiny dips in starlight as the planet crosses in front of its star.

What this page represents

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.

Signal quality
strong
Distance
215.1 ly
Star temp
5216 K
Mass
0.1 MJ (m·sin i)
What we can infer: broad planet class (rocky vs gas), rough irradiation band via star temperature + distance, and signal robustness.
What we can’t claim: surface conditions, biology, or breathable atmosphere without direct spectra.
overview
plain-language interpretation + what’s missing made explicit

This planet is about 2.5 times wider than Earth and 19 times more massive — making it a ‘sub-Neptune’ or ‘mini-Neptune’ type world. It orbits very close to its star, completing a full trip every 10.3 days. Its orbit is slightly oval-shaped, not perfectly circular. The planet’s estimated temperature is around 700 Kelvin (about 425°C or 800°F), which is very hot.

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.
Semi-major axis
0.09 AU
Meaning: average distance from the star (Earth = 1 AU).
Eccentricity
0.29
Meaning: how oval the orbit is (0 is a circle).
Host star type
—
A spectral label that summarizes temperature and color.
Host star radius
0.84 R⊙
Bigger stars can change how “hot” a planet’s orbit feels.
Metallicity
0.248
Meaning: how “heavy-element rich” the star is vs the Sun.
Distance
215.1 ly
How far the system is from Earth (in light-years).
About the numbers on this page: this profile combines measurements reported across multiple published studies. It uses the most consistent values and explains where estimates vary.
discovery and follow-up
why the same planet can appear in multiple catalog rows

HIP 97166 b was first reported in 2021 using the Transit method. The discovery is linked to observations from Transiting Exoplanet Survey Satellite (TESS).

In transit work, astronomers watch for tiny, repeating dips in a star’s light as the planet passes in front of it. Follow-up observations help rule out false positives and refine the orbit.

orbit and long-term stability
a plain-English read of the orbit, plus what “uncertainty” means here

The catalog lists an orbital period of about 10.29 days, a semi-major axis near 0.091 AU.

The orbit’s eccentricity is 0.29, 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.

Reader tip: small differences across studies usually reflect better data and improved fitting — not that the planet “changed.”
mass, “minimum mass,” and why estimates differ
radial velocity usually measures a minimum mass unless the orbit tilt is known

The archive reports a mass scale of 0.1 MJ.

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
Radial velocity detects a star’s wobble. If we don’t know the orbit’s tilt (inclination), the wobble gives a minimum mass. The true mass can be higher.
the host star in plain terms
star properties affect temperature estimates and “how intense” the orbit feels

HIP 97166 b orbits HIP 97166.

A temperature near 5216 K places it on the sun-like side of the main sequence. The system is about 215.1 light‑years away.

what we still don’t know
missing measurements that limit what anyone can responsibly claim

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. As new observations arrive, archives often refresh these entries (and sometimes revise earlier numbers).

Why this matters: without a measured radius or direct spectra, we can’t reliably infer density, surface conditions, or detailed chemistry.
observation charts
visual summaries from method + uncertainty bands (no spectra required)
radial velocity curve
Dashed segment indicates modeled RV window. Period: 10 d • e: 0.29 • a: 0.09 AU
orbit stability
signal-to-noise proxy
66% stability
Transit fit
Noise floor
Data density
This is a UI metric for confidence presentation — not a formal astrophysics rating.
what it might be made of (model-based)
If spectra is missing, these bars are browsing aids — not confirmed chemistry.
Mostly hydrogen & helium (gas giant envelope)

52% modeled
High clouds / haze (possible)

36% modeled
Carbon-bearing bands (possible)

32% modeled
These are presentation layers derived from planet class + irradiation band — not direct detections. Confirmed atmosphere claims require direct measurements (spectra).
Why scientists keep revisiting systems like this:

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. Transit systems are especially valuable because they can be re‑observed for decades to detect subtle changes in timing or additional planets.

discovery timeline
a readable story of how this planet entered the catalog
2021
First reported as a candidate planet by the TESS mission and follow-up studies.
2024
Confirmed and detailed in a published study by Polanski et al.
2024-07-23
Catalog row updated (parameters may change as analyses improve).
2026-02-01
Profile rendered from the current catalog snapshot.
sources
NASA Exoplanet Archive (row-level fields)
Method metadata and derived UI bands (model-only)
No spectral claims are made without spectra.
Transparency: This page is a plain-language summary built from published catalog values. If newer studies revise any numbers, this profile will evolve with them.
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