Key parameters at a glance
- A mass of 2,097.99 Earth masses
- An orbital period of 16.812 days
- Semi-major axis 0.1187 AU
- Equilibrium temperature 558 K (285 °C)
- Distance from Earth 90.62 light-years
- Travel time at Voyager 1 speed 1,598,086 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around HD 176986
HD 176986 c 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 |
|---|---|---|---|---|---|---|
| HD 176986 b | Unclassified | — | 1,487.75 | 6.492 | 767 | 2017 |
| HD 176986 c this | Unclassified | — | 2,097.99 | 16.812 | 558 | 2017 |
| HD 176986 d | Sub-Neptune | 2.49 | 6.76 | 61.376 | 363 | 2026 |
HD 176986 c Planet Profile
Physical Specs
Classification
Planet Type
Unclassified
Discovery
| Metric | Earth | HD 176986 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | — | 11.21 |
| Mass (M⊕) | 1.00 | 2,097.99 | 317.83 |
| Density (g/cm³) | 5.51 | — | 1.33 |
| Surface Gravity (g) | 1.00 | — | 2.53 |
| Insolation (S⊕) | 1.00 | 22.90 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 2,097.985 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 9.750 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 176986
HIP
HIP 93540
TIC
TIC 39554091
Gaia DR2
Gaia DR2 4199396753205879040
Gaia DR3
Gaia DR3 4199396753205879040
System
HD 176986
Percentile among Unclassified cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 16.81 Earth days (4.6% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1187 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
2.840 m/s
Transit mid-time (BJD)
2,460,614.6900
Long. of periastron (ω)
270.00°
Angular separation (arcsec)
4.27000
Eq. Temperature
558K
(285 °C)
Insolation (S⊕)
22.90
Earth = 1.00
Earth Similarity (ESI)
—
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Su Aacute Rez Mascare Ntilde O et al. 2018Instrument
Multiple Instruments
Publication
2018-04
Observation locale
Ground
Discovery cohort
Planets confirmed in 2017 at Multiple Observatories (12 shown).
Host System: HD 176986
Spectral Class
K-type orange
Effective Temperature
4,931 K — cooler than the Sun (5,778 K)
Estimated Age
4.30 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.782 R☉
Stellar Mass
0.789 M☉
Metallicity [Fe/H]
0.03
Extended Stellar Properties
Surface gravity (log g)
4.440 dex
Stellar density
2.296 g/cm³
Systemic radial velocity
37.42 km/s
Rotational v·sin i
1.10 km/s
Rotation period
36.05 days
Activity index (log R'HK)
-4.900
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 7 bands
Astrometric Data
Parallax
35.963 mas
Total Proper Motion
267.892 mas/yr
PM Right Ascension
-126.94 mas/yr
PM Declination
-235.91 mas/yr
Galactic Cartesian (pc)
x = 0.267 · y = -0.945 · z = -0.192
Equatorial (J2000)
RA 285.77391° · Dec -11.04494°
Galactic ℓ, b
24.360° · -7.572°
Ecliptic λ, β
285.798° · 11.533°
HTM-20 index
1842930316
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