Key parameters at a glance
- A radius of 2.75 Earth radii
- A mass of 8.00 Earth masses
- Surface gravity around 1.06 g
- An orbital period of 16.432 days
- Semi-major axis 0.1240 AU
- Equilibrium temperature 642 K (369 °C)
- Distance from Earth 215.10 light-years
- Earth Similarity Index 0.380
- Travel time at Voyager 1 speed 3,793,292 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around HIP 97166
HIP 97166 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| HIP 97166 b | Sub-Neptune | 2.48 | 19.10 | 10.289 | 702 | 2021 |
| HIP 97166 c this | Sub-Neptune | 2.75 | 8.00 | 16.432 | 642 | 2021 |
HIP 97166 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#804of 1978
top 40.6%
This planet
2.75R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | HIP 97166 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.75 | 11.21 |
| Mass (M⊕) | 1.00 | 8.00 | 317.83 |
| Density (g/cm³) | 5.51 | 2.11 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.06 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 8.000 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HIP
HIP 97166
TIC
TIC 237222864
Gaia DR2
Gaia DR2 2288221003213039488
Gaia DR3
Gaia DR3 2288221003213039488
System
HIP 97166
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 16.43 Earth days (4.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1240 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
2.120 m/s
Transit mid-time (BJD)
2,458,694.0000
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
1.88000
Eq. Temperature
642K
(369 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.380
0 = alien, 1 = Earth-identical
Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Macdougall et al. 2021Instrument
Multiple Instruments
Publication
2021-12
Observation locale
Ground
Discovery cohort
Planets confirmed in 2021 at Multiple Observatories (12 shown).
Host System: HIP 97166
Spectral Class
K-type orange
Effective Temperature
5,216 K — cooler than the Sun (5,778 K)
Estimated Age
1.20 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.842 R☉
Stellar Mass
0.934 M☉
Metallicity [Fe/H]
0.25
Extended Stellar Properties
Surface gravity (log g)
4.557 dex
Stellar density
2.193 g/cm³
Activity index (log R'HK)
-5.010
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
15.134 mas
Total Proper Motion
33.636 mas/yr
PM Right Ascension
18.62 mas/yr
PM Declination
28.01 mas/yr
Galactic Cartesian (pc)
x = 0.121 · y = -0.246 · z = 0.962
Equatorial (J2000)
RA 296.24462° · Dec 74.06286°
Galactic ℓ, b
106.132° · 22.451°
Ecliptic λ, β
52.196° · 78.574°
HTM-20 index
-997005122
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