Key parameters at a glance
- A radius of 9.17 Earth radii
- A mass of 60.50 Earth masses
- Surface gravity around 0.72 g
- An orbital period of 14.277 days
- Semi-major axis 0.1228 AU
- Equilibrium temperature 1,315 K (1042 °C)
- Distance from Earth 311.64 light-years
- Earth Similarity Index 0.103
- Travel time at Voyager 1 speed 5,495,710 years
- Almost certainly tidally locked to its host star given the close orbit
HD 221416 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#72of 574
top 12.4%
This planet
9.17R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | HD 221416 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 9.17 | 11.21 |
| Mass (M⊕) | 1.00 | 60.50 | 317.83 |
| Density (g/cm³) | 5.51 | 0.43 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.72 | 2.53 |
| Insolation (S⊕) | 1.00 | 495.91 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 60.500 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
HD
HD 221416
HIP
HIP 116158
TIC
TIC 441462736
Gaia DR2
Gaia DR2 2388463203438164096
Gaia DR3
Gaia DR3 2388463203438164096
System
HD 221416
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 14.28 Earth days (3.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1228 AU.
Transit Fingerprint
Depth
0.076 %
Duration
8.571 h
Impact parameter b
0.728
Rp / R★
0.028540
Transit midpoint (BJD)
2,458,357.0149
Photometric dip
Transit produces a flux drop of 763 ppm lasting ≈ 8.57 h.
Extended Orbital Architecture
Planet / star radius ratio
0.028540
Semi-major axis / stellar radius
8.970
Impact parameter (b)
0.728
RV semi-amplitude (K)
14.100 m/s
Transit mid-time (BJD)
2,458,357.0149
Long. of periastron (ω)
-106.00°
Angular separation (arcsec)
1.29000
Eq. Temperature
1,315K
(1042 °C)
Insolation (S⊕)
495.91
Earth = 1.00
Earth Similarity (ESI)
0.103
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. Close-orbiting tidally-locked around a cool host.
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
Huber et al. 2019Instrument
TESS CCD Array
Publication
2019-06
Observation locale
Space
Discovery cohort
Planets confirmed in 2019 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: HD 221416
Spectral Class
K-type orange
Effective Temperature
5,080 K — cooler than the Sun (5,778 K)
Estimated Age
4.90 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
2.943 R☉
Stellar Mass
1.212 M☉
Metallicity [Fe/H]
-0.08
Extended Stellar Properties
Surface gravity (log g)
3.584 dex
Stellar density
0.067 g/cm³
Systemic radial velocity
25.29 km/s
Rotational v·sin i
2.80 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
10.438 mas
Total Proper Motion
109.503 mas/yr
PM Right Ascension
-96.77 mas/yr
PM Declination
51.24 mas/yr
Galactic Cartesian (pc)
x = 0.922 · y = -0.113 · z = -0.371
Equatorial (J2000)
RA 353.03319° · Dec -21.80120°
Galactic ℓ, b
45.073° · -71.209°
Ecliptic λ, β
344.758° · -17.214°
HTM-20 index
2053612391
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