Confirmed Exoplanet Discovered 2016

HD 164922 c

A sub-neptune orbiting the g-type yellow (sun-like) HD 164922, located approximately 71.8 light-years from Earth.

Key parameters at a glance

  • A radius of 3.66 Earth radii
  • A mass of 13.00 Earth masses
  • Surface gravity around 0.97 g
  • An orbital period of 75.740 days
  • Semi-major axis 0.3410 AU
  • Equilibrium temperature 401 K (127 °C)
  • Distance from Earth 71.76 light-years
  • Earth Similarity Index 0.514
  • Travel time at Voyager 1 speed 1,265,479 years

Context from the literature

HD 164922 c is an exoplanet orbiting the star HD 164922 about 72 light-years from Earth in the constellation Hercules. The exoplanet was found by using the radial velocity method, from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.

Excerpted from Wikipedia · full article

3 siblings around HD 164922

HD 164922 c shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
HD 164922 d Super-Earth 1.83 4.00 12.458 — 2020
HD 164922 e Sub-Neptune 3.23 10.52 41.763 — 2021
HD 164922 c this Sub-Neptune 3.66 13.00 75.740 401 2016
HD 164922 b Gas Giant 13.30 116.00 1,207.000 159 2005

HD 164922 c Planet Profile

Physical Specs

Radius
3.66 R⊕
Radius (Jupiter)
0.327 R♃
Mass
13.00 M⊕
Mass (Jupiter)
0.041 M♃
Density
1.46 g/cm³
Surface Gravity
0.97 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.514
HZ Position Inner
Controversial No

Discovery

Year 2016
Method Radial Velocity
Facility Multiple Observatories
Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#107of 1978

top 5.4%

This planet

3.66R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-1691 b 3.66 R⊕ TOI-1130 b 3.66 R⊕ GJ 27.1 b 3.66 R⊕
Metric Earth HD 164922 c Jupiter
Radius (R⊕)1.003.6611.21
Mass (M⊕)1.0013.00317.83
Density (g/cm³)5.511.461.33
Surface Gravity (g)1.000.972.53
Insolation (S⊕)1.006.290.037

Alternative Mass Estimates

Method Value Interpretation
Minimum mass (M sin i) 13.000 M⊕ Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD

HD 164922

HIP

HIP 88348

TIC

TIC 159019691

Gaia DR2

Gaia DR2 4582680493669880704

Gaia DR3

Gaia DR3 4582680493669880704

System

HD 164922

Percentile among Sub-Neptune cohort

Radius 3.660 R⊕ · percentile 94 / cohort 1978
Mass 13.000 M⊕ · percentile 87 / cohort 1978
Orbital period 75.74 d · percentile 91 / cohort 1946
Distance 22.00 pc · percentile 5 / cohort 1975
ESI 0.514 · percentile 72 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
75.740 days
Semi-major axis
0.3410 AU
Eccentricity
0.120
Inclination
— °

Year Length

A year here lasts approximately 75.74 Earth days (20.7% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.3410 AU.

Extended Orbital Architecture

Semi-major axis / stellar radius

72.100

RV semi-amplitude (K)

2.200 m/s

Transit mid-time (BJD)

2,455,221.1000

Long. of periastron (ω)

-29.00°

Angular separation (arcsec)

15.50000

Eq. Temperature

401K

(127 °C)

Insolation (S⊕)

6.29

Earth = 1.00

Earth Similarity (ESI)

0.514

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Fulton et al. 2016

Instrument

Multiple Instruments

Publication

2016-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2016 at Multiple Observatories (12 shown).

HD 42618 b · Sub-Neptune HD 224538 b · Gas Giant HD 30177 c · Gas Giant Kepler-56 d · Gas Giant HD 72892 b · Gas Giant HD 147873 b · Gas Giant HIP 8541 b · Gas Giant HD 68402 b · Gas Giant HD 86950 b · Gas Giant HD 165155 b · Gas Giant rho CrB c · Neptune-like HIP 74890 b · Gas Giant

Host System: HD 164922

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,390 K — cooler than the Sun (5,778 K)

Estimated Age

9.58 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.946 R☉

Stellar Mass

0.926 M☉

Metallicity [Fe/H]

0.18

Extended Stellar Properties

Surface gravity (log g)

4.460 dex

Stellar density

1.320 g/cm³

Systemic radial velocity

20.36 km/s

Rotational v·sin i

2.00 km/s

Rotation period

42.30 days

Activity index (log R'HK)

-5.050

Metallicity ratio

[Fe/H]

Distance
22.00 parsec
Light-years 71.76 ly
V-band magnitude
7.01 mag
Voyager-speed travel 1,265,479 yr

Multi-band Host Photometry — 11 bands

5.07.87.81B7.01V6.79Gaia6.28TESS5.55J5.20H5.11K5.12W15.02W25.16W35.11W4

Astrometric Data

Parallax

45.422 mas

Total Proper Motion

717.364 mas/yr

PM Right Ascension

389.65 mas/yr

PM Declination

-602.31 mas/yr

Galactic Cartesian (pc)

x = 0.010 · y = -0.896 · z = 0.443

Equatorial (J2000)

RA 270.63047° · Dec 26.31041°

Galactic ℓ, b

52.296° · 21.783°

Ecliptic λ, β

270.871° · 49.748°

HTM-20 index

-1181639783

Observation Record

Photometric series

1

RV measurements

1

Stellar spectra

6

Archive notes

2

Wikipedia →

Similar Worlds

TOI-1691 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 3.66 R⊕ · 363.5 ly

Kepler-1128 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 3.65 R⊕ · 3,533.6 ly

WASP-47 d

Sub-Neptune · G-type yellow (Sun-like)

Radius 3.65 R⊕ · 863.6 ly

EPIC 249893012 c

Sub-Neptune · G-type yellow (Sun-like)

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Kepler-1775 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 3.65 R⊕ · 2,142.9 ly

K2-194 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 3.64 R⊕ · 2,053.2 ly

Explore Related Categories

Sub-Neptune Planets Radial Velocity Discoveries Multiple Observatories Mission G-type yellow (Sun-like) Hosts