Confirmed Exoplanet Discovered 2018

K2-275 b

A sub-neptune orbiting the k-type orange K2-275, located approximately 402.6 light-years from Earth.

Key parameters at a glance

  • A radius of 2.34 Earth radii
  • A mass of 6.08 Earth masses
  • Surface gravity around 1.11 g
  • An orbital period of 3.281 days
  • Semi-major axis 0.0277 AU
  • Equilibrium temperature 1,166 K (893 °C)
  • Distance from Earth 402.60 light-years
  • Earth Similarity Index 0.217
  • Travel time at Voyager 1 speed 7,099,858 years
  • Almost certainly tidally locked to its host star given the close orbit

1 sibling around K2-275

K2-275 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
K2-275 b this Sub-Neptune 2.34 6.08 3.281 1,166 2018
K2-275 c Sub-Neptune 2.21 5.52 8.439 653 2018

K2-275 b Planet Profile

Physical Specs

Radius
2.34 R⊕
Radius (Jupiter)
0.209 R♃
Mass
6.08 M⊕
Mass (Jupiter)
0.019 M♃
Density
2.61 g/cm³
Surface Gravity
1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.217
HZ Position Inner
Controversial No

Discovery

Year 2018
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1429of 1978

top 72.2%

This planet

2.34R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth K2-275 b Jupiter
Radius (R⊕)1.002.3411.21
Mass (M⊕)1.006.08317.83
Density (g/cm³)5.512.611.33
Surface Gravity (g)1.001.112.53
Insolation (S⊕)1.00161.250.037

Star Catalogue Identifiers

TIC

TIC 332022997

Gaia DR2

Gaia DR2 661598415839633024

Gaia DR3

Gaia DR3 661598415839633024

System

K2-275

Percentile among Sub-Neptune cohort

Radius 2.340 R⊕ · percentile 27 / cohort 1978
Mass 6.080 M⊕ · percentile 26 / cohort 1978
Orbital period 3.28 d · percentile 6 / cohort 1946
Distance 123.44 pc · percentile 23 / cohort 1975
ESI 0.217 · percentile 9 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
3.281 days
Semi-major axis
0.0277 AU
Eccentricity
Inclination
88.02 °

Year Length

A year here lasts approximately 3.28 Earth days (0.9% of a terrestrial year) at a mean orbital distance of 0.0277 AU.

Transit Fingerprint

Depth

0.097 %

Duration

1.930 h

Impact parameter b

0.770

Rp / R★

0.031100

Transit midpoint (BJD)

2,457,142.1340

Photometric dip

Transit produces a flux drop of 968 ppm lasting ≈ 1.93 h.

Extended Orbital Architecture

Planet / star radius ratio

0.031100

Semi-major axis / stellar radius

8.610

Impact parameter (b)

0.770

Transit mid-time (BJD)

2,457,142.1340

Angular separation (arcsec)

0.22400

Eq. Temperature

1,166K

(893 °C)

Insolation (S⊕)

161.25

Earth = 1.00

Earth Similarity (ESI)

0.217

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.

Discovery Paper

Primary reference

Livingston et al. 2018

Instrument

Kepler CCD Array

Publication

2018-12

Observation locale

Space

Host System: K2-275

Spectral Class

K-type orange

Effective Temperature

4,841 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.690 R☉

Stellar Mass

0.770 M☉

Metallicity [Fe/H]

-0.06

Extended Stellar Properties

Surface gravity (log g)

4.650 dex

Stellar density

2.737 g/cm³

Systemic radial velocity

-7.35 km/s

Metallicity ratio

[Fe/H]

Distance
123.44 parsec
Light-years 402.60 ly
V-band magnitude
11.97 mag
Voyager-speed travel 7,099,858 yr

Multi-band Host Photometry — 12 bands

8.013.113.09B11.97V11.81Gaia11.75Kepler11.20TESS10.36J9.86H9.75K9.64W19.72W29.65W37.99W4

Astrometric Data

Parallax

8.073 mas

Total Proper Motion

16.382 mas/yr

PM Right Ascension

-4.87 mas/yr

PM Declination

-15.64 mas/yr

Galactic Cartesian (pc)

x = -0.629 · y = 0.694 · z = 0.349

Equatorial (J2000)

RA 132.16988° · Dec 20.45502°

Galactic ℓ, b

205.824° · 34.581°

Ecliptic λ, β

129.018° · 2.545°

HTM-20 index

1703794800

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