Key parameters at a glance
- A radius of 3.18 Earth radii
- A mass of 10.26 Earth masses
- Surface gravity around 1.01 g
- An orbital period of 35.450 days
- Semi-major axis 0.1980 AU
- Distance from Earth 63.77 light-years
- Earth Similarity Index 0.620
- Travel time at Voyager 1 speed 1,124,584 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around HD 216520
HD 216520 b 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 |
|---|---|---|---|---|---|---|
| HD 216520 b this | Sub-Neptune | 3.18 | 10.26 | 35.450 | — | 2020 |
| HD 216520 c | Sub-Neptune | 3.03 | 9.44 | 154.430 | — | 2020 |
HD 216520 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#367of 1978
top 18.5%
This planet
3.18R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | HD 216520 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.18 | 11.21 |
| Mass (M⊕) | 1.00 | 10.26 | 317.83 |
| Density (g/cm³) | 5.51 | 1.75 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.01 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 10.260 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 216520
HIP
HIP 112527
TIC
TIC 264899051
Gaia DR2
Gaia DR2 2299942278201276288
Gaia DR3
Gaia DR3 2299942278201276288
System
HD 216520
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 35.45 Earth days (9.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1980 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
2.280 m/s
Transit mid-time (BJD)
2,455,216.8000
Long. of periastron (ω)
220.95°
Angular separation (arcsec)
10.10000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.620
0 = alien, 1 = Earth-identical
Insufficient insolation data. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Burt et al. 2021Instrument
Multiple Instruments
Publication
2021-01
Observation locale
Ground
Discovery cohort
Planets confirmed in 2020 at Multiple Observatories (12 shown).
Host System: HD 216520
Spectral Class
K-type orange
Effective Temperature
5,103 K — cooler than the Sun (5,778 K)
Estimated Age
6.00 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.760 R☉
Stellar Mass
0.820 M☉
Metallicity [Fe/H]
-0.16
Extended Stellar Properties
Surface gravity (log g)
4.540 dex
Stellar density
2.395 g/cm³
Systemic radial velocity
-18.54 km/s
Rotational v·sin i
0.20 km/s
Activity index (log R'HK)
-4.980
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
51.117 mas
Total Proper Motion
191.433 mas/yr
PM Right Ascension
-151.64 mas/yr
PM Declination
116.85 mas/yr
Galactic Cartesian (pc)
x = 0.104 · y = -0.034 · z = 0.994
Equatorial (J2000)
RA 341.87687° · Dec 83.69753°
Galactic ℓ, b
119.445° · 21.683°
Ecliptic λ, β
74.004° · 67.747°
HTM-20 index
1565580697
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Radius 3.15 R⊕ · 1,635.9 ly