Confirmed Exoplanet Discovered 2016

HD 3167 c

A sub-neptune orbiting the k-type orange HD 3167, located approximately 154.2 light-years from Earth.

Key parameters at a glance

  • A radius of 3.00 Earth radii
  • A mass of 11.13 Earth masses
  • Surface gravity around 1.24 g
  • An orbital period of 29.845 days
  • Semi-major axis 0.1776 AU
  • Equilibrium temperature 564 K (291 °C)
  • Distance from Earth 154.24 light-years
  • Earth Similarity Index 0.419
  • Travel time at Voyager 1 speed 2,720,002 years
  • Almost certainly tidally locked to its host star given the close orbit

Context from the literature

HD 3167 is a single, orange-hued star in the zodiac constellation of Pisces that hosts a system with four exoplanets. The star is too faint to be seen with the naked eye, having an apparent visual magnitude of 8.97. The distance to HD 3167 can be determined from its annual parallax shift of 21.1363 mas as measured by the Gaia space observatory, yielding a range of 154 light years. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.204″ per year. Since it was first photographed during the Palomar observatory sky survey in 1953, it had moved over 12.5″ by 2017. The star is moving away from the Earth with an average heliocentric radial velocity of +19.5 km/s.

Excerpted from Wikipedia · full article

3 siblings around HD 3167

HD 3167 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 3167 b Super-Earth 1.67 4.97 0.960 1,774 2016
HD 3167 d Super-Earth 1.92 4.33 8.411 860 2017
HD 3167 c this Sub-Neptune 3.00 11.13 29.845 564 2016
HD 3167 e Sub-Neptune 2.83 8.41 96.630 375 2022

HD 3167 c Planet Profile

Physical Specs

Radius
3.00 R⊕
Radius (Jupiter)
0.268 R♃
Mass
11.13 M⊕
Mass (Jupiter)
0.035 M♃
Density
2.11 g/cm³
Surface Gravity
1.24 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.419
HZ Position Inner
Controversial No

Discovery

Year 2016
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#521of 1978

top 26.3%

This planet

3.00R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth HD 3167 c Jupiter
Radius (R⊕)1.003.0011.21
Mass (M⊕)1.0011.13317.83
Density (g/cm³)5.512.111.33
Surface Gravity (g)1.001.242.53
Insolation (S⊕)1.0016.900.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 11.130 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

HD

HD 3167

HIP

HIP 2736

TIC

TIC 318707987

Gaia DR2

Gaia DR2 2554032474712538880

Gaia DR3

Gaia DR3 2554032474712538880

System

HD 3167

Percentile among Sub-Neptune cohort

Radius 3.000 R⊕ · percentile 73 / cohort 1978
Mass 11.130 M⊕ · percentile 81 / cohort 1978
Orbital period 29.85 d · percentile 73 / cohort 1946
Distance 47.29 pc · percentile 11 / cohort 1975
ESI 0.419 · percentile 56 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
29.845 days
Semi-major axis
0.1776 AU
Eccentricity
0.060
Inclination
89.30 °

Year Length

A year here lasts approximately 29.85 Earth days (8.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1776 AU.

Transit Fingerprint

Depth

0.095 %

Duration

4.869 h

Impact parameter b

0.451

Rp / R★

0.030060

Transit midpoint (BJD)

2,457,394.9788

Photometric dip

Transit produces a flux drop of 946 ppm lasting ≈ 4.87 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030060

Semi-major axis / stellar radius

44.010

Impact parameter (b)

0.451

RV semi-amplitude (K)

2.580 m/s

Transit mid-time (BJD)

2,457,394.9788

Long. of periastron (ω)

178.00°

Sky-projected obliquity (λ)

-108.90°

True obliquity (ψ)

107.70°

Angular separation (arcsec)

3.76000

Eq. Temperature

564K

(291 °C)

Insolation (S⊕)

16.90

Earth = 1.00

Earth Similarity (ESI)

0.419

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.

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

Vanderburg et al. 2016

Instrument

Kepler CCD Array

Publication

2016-09

Observation locale

Space

Host System: HD 3167

Spectral Class

K-type orange

Effective Temperature

5,261 K — cooler than the Sun (5,778 K)

Estimated Age

7.80 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.880 R☉

Stellar Mass

0.837 M☉

Metallicity [Fe/H]

0.04

Extended Stellar Properties

Surface gravity (log g)

4.530 dex

Stellar density

1.817 g/cm³

Systemic radial velocity

19.53 km/s

Rotational v·sin i

2.41 km/s

Rotation period

23.52 days

Activity index (log R'HK)

-5.040

Metallicity ratio

[Fe/H]

Distance
47.29 parsec
Light-years 154.24 ly
V-band magnitude
8.97 mag
Voyager-speed travel 2,720,002 yr

Multi-band Host Photometry — 12 bands

6.99.89.77B8.97V8.76Gaia8.95Kepler8.25TESS7.55J7.20H7.07K6.94W17.09W27.05W37.07W4

Astrometric Data

Parallax

21.118 mas

Total Proper Motion

203.880 mas/yr

PM Right Ascension

107.41 mas/yr

PM Declination

-173.29 mas/yr

Galactic Cartesian (pc)

x = 0.986 · y = 0.152 · z = 0.076

Equatorial (J2000)

RA 8.74015° · Dec 4.38072°

Galactic ℓ, b

115.111° · -58.241°

Ecliptic λ, β

9.749° · 0.562°

HTM-20 index

-1000385905

Observation Record

Photometric series

1

Transmission spectra

4

Archive notes

2

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