Key parameters at a glance
- A radius of 18.49 Earth radii
- A mass of 435.41 Earth masses
- Surface gravity around 1.27 g
- An orbital period of 7.794 days
- Semi-major axis 0.0769 AU
- Equilibrium temperature 882 K (609 °C)
- Distance from Earth 874.23 light-years
- Earth Similarity Index 0.131
- Travel time at Voyager 1 speed 15,417,077 years
Kepler-447 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#56of 1771
top 3.1%
This planet
18.49R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | Kepler-447 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 18.49 | 11.21 |
| Mass (M⊕) | 1.00 | 435.41 | 317.83 |
| Density (g/cm³) | 5.51 | 0.40 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.27 | 2.53 |
| Insolation (S⊕) | 1.00 | 119.04 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 435.410 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 48506505
Gaia DR2
Gaia DR2 2131587531660567296
Gaia DR3
Gaia DR3 2131587531660567296
System
Kepler-447
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 7.79 Earth days (2.1% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0769 AU.
Transit Fingerprint
Depth
0.339 %
Duration
1.135 h
Impact parameter b
1.076
Rp / R★
0.165000
Transit midpoint (BJD)
2,454,970.2598
Photometric dip
Transit produces a flux drop of 3,387 ppm lasting ≈ 1.14 h.
Extended Orbital Architecture
Planet / star radius ratio
0.165000
Semi-major axis / stellar radius
20.410
Impact parameter (b)
1.076
RV semi-amplitude (K)
141.000 m/s
Transit mid-time (BJD)
2,454,970.2598
Long. of periastron (ω)
98.30°
Angular separation (arcsec)
0.28700
Eq. Temperature
882K
(609 °C)
Insolation (S⊕)
119.04
Earth = 1.00
Earth Similarity (ESI)
0.131
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Lillo Box et al. 2015Instrument
Kepler CCD Array
Publication
2015-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2015 at Kepler (12 shown).
Host System: Kepler-447
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,493 K — cooler than the Sun (5,778 K)
Estimated Age
1.62 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.050 R☉
Stellar Mass
1.000 M☉
Metallicity [Fe/H]
0.07
Extended Stellar Properties
Surface gravity (log g)
4.400 dex
Stellar density
1.460 g/cm³
Systemic radial velocity
1.39 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
3.702 mas
Total Proper Motion
24.172 mas/yr
PM Right Ascension
-5.74 mas/yr
PM Declination
-23.48 mas/yr
Galactic Cartesian (pc)
x = 0.174 · y = -0.638 · z = 0.750
Equatorial (J2000)
RA 285.26853° · Dec 48.55988°
Galactic ℓ, b
78.727° · 18.486°
Ecliptic λ, β
301.213° · 70.349°
HTM-20 index
-26534568
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