Key parameters at a glance
- A radius of 12.60 Earth radii
- A mass of 2,669.76 Earth masses
- Surface gravity around 16.82 g
- An orbital period of 522.200 days
- Semi-major axis 1.4300 AU
- Equilibrium temperature 390 K (117 °C)
- Distance from Earth 1,693.50 light-years
- Earth Similarity Index 0.406
- Travel time at Voyager 1 speed 29,864,810 years
1 sibling around K2-99
K2-99 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 |
|---|---|---|---|---|---|---|
| K2-99 b | Gas Giant | 11.88 | 276.51 | 18.248 | 1,184 | 2016 |
| K2-99 c this | Gas Giant | 12.60 | 2,669.76 | 522.200 | 390 | 2022 |
K2-99 c Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1179of 1771
top 66.5%
This planet
12.60R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | K2-99 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 12.60 | 11.21 |
| Mass (M⊕) | 1.00 | 2,669.76 | 317.83 |
| Density (g/cm³) | 5.51 | 7.33 | 1.33 |
| Surface Gravity (g) | 1.00 | 16.82 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 2,669.759 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
TIC
TIC 176966903
Gaia DR2
Gaia DR2 3620612011248988416
Gaia DR3
Gaia DR3 3620612011248988416
System
K2-99
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts about 1.43 Earth years on a mildly elliptical path at a mean orbital distance of 1.4300 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
170.000 m/s
Transit mid-time (BJD)
2,458,104.2000
Long. of periastron (ω)
13.00°
Angular separation (arcsec)
2.75000
Eq. Temperature
390K
(117 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.406
0 = alien, 1 = Earth-identical
Insufficient insolation data — the surface is too hot to retain surface water.
Discovery Paper
Primary reference
Smith et al. 2022Instrument
Multiple Instruments
Publication
2022-03
Observation locale
Ground
Discovery cohort
Planets confirmed in 2022 at Multiple Observatories (12 shown).
Host System: K2-99
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
6,069 K — hotter than the Sun (5,778 K)
Estimated Age
3.70 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
2.550 R☉
Stellar Mass
1.440 M☉
Metallicity [Fe/H]
0.20
Extended Stellar Properties
Surface gravity (log g)
3.783 dex
Stellar density
0.078 g/cm³
Systemic radial velocity
-2.86 km/s
Rotational v·sin i
9.30 km/s
Activity index (log R'HK)
-5.393
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
1.898 mas
Total Proper Motion
2.014 mas/yr
PM Right Ascension
-0.32 mas/yr
PM Declination
-1.99 mas/yr
Galactic Cartesian (pc)
x = -0.873 · y = -0.479 · z = -0.095
Equatorial (J2000)
RA 208.77376° · Dec -5.44249°
Galactic ℓ, b
330.586° · 53.976°
Ecliptic λ, β
208.678° · 5.946°
HTM-20 index
247804284
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