Key parameters at a glance
- A radius of 2.50 Earth radii
- A mass of 6.80 Earth masses
- Surface gravity around 1.09 g
- An orbital period of 77.474 days
- Semi-major axis 0.3050 AU
- Equilibrium temperature 277 K (4 °C)
- Distance from Earth 1,690.15 light-years
- Earth Similarity Index 0.748
- Travel time at Voyager 1 speed 29,805,854 years
Context from the literature
Kepler-298d is an exoplanet orbiting within the habitable zone of the orange dwarf star Kepler-298, located 1545 light years away from Earth. It was discovered in 2014 via the transit method. The planet was originally considered to be potentially habitable, but further research places its atmosphere at +2.11 on the HZA scale, meaning it may be an ocean planet with a thick gas atmosphere like a gas dwarf.
Excerpted from Wikipedia · full article
2 siblings around Kepler-298
Kepler-298 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-298 b | Super-Earth | 1.96 | 4.50 | 10.475 | 540 | 2014 |
| Kepler-298 c | Super-Earth | 1.93 | 4.38 | 22.929 | 416 | 2014 |
| Kepler-298 d this | Sub-Neptune | 2.50 | 6.80 | 77.474 | 277 | 2014 |
Kepler-298 d Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1168of 1978
top 59.0%
This planet
2.50R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-298 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.50 | 11.21 |
| Mass (M⊕) | 1.00 | 6.80 | 317.83 |
| Density (g/cm³) | 5.51 | 2.39 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.09 | 2.53 |
| Insolation (S⊕) | 1.00 | 1.72 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 48217868
Gaia DR2
Gaia DR2 2143758128946411904
Gaia DR3
Gaia DR3 2143758128946411904
System
Kepler-298
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 77.47 Earth days (21.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.3050 AU.
Transit Fingerprint
Depth
0.154 %
Duration
4.433 h
Impact parameter b
0.750
Rp / R★
0.040650
Transit midpoint (BJD)
2,455,017.2474
Photometric dip
Transit produces a flux drop of 1,544 ppm lasting ≈ 4.43 h.
Extended Orbital Architecture
Planet / star radius ratio
0.040650
Semi-major axis / stellar radius
95.000
Impact parameter (b)
0.750
Transit mid-time (BJD)
2,455,017.2474
Angular separation (arcsec)
0.58900
Eq. Temperature
277K
(4 °C)
Insolation (S⊕)
1.72
Earth = 1.00
Earth Similarity (ESI)
0.748
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure.
Discovery Paper
Primary reference
Rowe et al. 2014Instrument
Kepler CCD Array
Publication
2014-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2014 at Kepler (12 shown).
Host System: Kepler-298
Spectral Class
K-type orange
Effective Temperature
4,465 K — cooler than the Sun (5,778 K)
Estimated Age
2.40 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.582 R☉
Stellar Mass
0.660 M☉
Metallicity [Fe/H]
-0.21
Extended Stellar Properties
Surface gravity (log g)
4.709 dex
Stellar density
6.832 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.901 mas
Total Proper Motion
10.336 mas/yr
PM Right Ascension
6.29 mas/yr
PM Declination
-8.20 mas/yr
Galactic Cartesian (pc)
x = 0.149 · y = -0.641 · z = 0.753
Equatorial (J2000)
RA 283.03984° · Dec 48.82533°
Galactic ℓ, b
78.470° · 19.961°
Ecliptic λ, β
297.195° · 71.036°
HTM-20 index
1908993741
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