Confirmed Exoplanet Discovered 2020

L 168-9 b

A super-earth orbiting the m-type red dwarf L 168-9, located approximately 82.0 light-years from Earth.

Key parameters at a glance

  • A radius of 1.63 Earth radii
  • A mass of 4.07 Earth masses
  • Surface gravity around 1.53 g
  • An orbital period of 1.402 days
  • Semi-major axis 0.0208 AU
  • Equilibrium temperature 998 K (725 °C)
  • Distance from Earth 82.03 light-years
  • Earth Similarity Index 0.297
  • Travel time at Voyager 1 speed 1,446,545 years
  • Almost certainly tidally locked to its host star given the close orbit

L 168-9 b Planet Profile

Physical Specs

Radius
1.63 R⊕
Radius (Jupiter)
0.145 R♃
Mass
4.07 M⊕
Mass (Jupiter)
0.013 M♃
Density
5.18 g/cm³
Surface Gravity
1.53 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.297
HZ Position Inner
Controversial No

Discovery

Year 2020
Method Transit
Facility Transiting Exoplanet Survey Satellite (TESS)
Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#517of 1176

top 43.9%

This planet

1.63R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth L 168-9 b Jupiter
Radius (R⊕)1.001.6311.21
Mass (M⊕)1.004.07317.83
Density (g/cm³)5.515.181.33
Surface Gravity (g)1.001.532.53
Insolation (S⊕)1.00149.370.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 4.070 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

HIP

HIP 115211

TIC

TIC 234994474

Gaia DR2

Gaia DR2 6491962296196145664

Gaia DR3

Gaia DR3 6491962300492857472

System

L 168-9

Percentile among Super-Earth cohort

Radius 1.630 R⊕ · percentile 55 / cohort 1176
Mass 4.070 M⊕ · percentile 76 / cohort 1176
Orbital period 1.40 d · percentile 8 / cohort 1164
Distance 25.15 pc · percentile 5 / cohort 1171
ESI 0.297 · percentile 36 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
1.402 days
Semi-major axis
0.0208 AU
Eccentricity
0.000
Inclination
84.27 °

Year Length

A year here lasts approximately 1.40 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0208 AU.

Transit Fingerprint

Depth

0.059 %

Duration

1.020 h

Impact parameter b

0.740

Rp / R★

0.024700

Transit midpoint (BJD)

2,459,082.8568

Photometric dip

Transit produces a flux drop of 594 ppm lasting ≈ 1.02 h.

Extended Orbital Architecture

Planet / star radius ratio

0.024700

Semi-major axis / stellar radius

8.610

Impact parameter (b)

0.740

RV semi-amplitude (K)

3.200 m/s

Transit mid-time (BJD)

2,459,082.8568

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

0.82700

Eq. Temperature

998K

(725 °C)

Insolation (S⊕)

149.37

Earth = 1.00

Earth Similarity (ESI)

0.297

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

Instrument

TESS CCD Array

Publication

2020-04

Observation locale

Space

Host System: L 168-9

Spectral Class

M-type red dwarf

Effective Temperature

3,842 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.604 R☉

Stellar Mass

0.614 M☉

Metallicity [Fe/H]

-0.03

Extended Stellar Properties

Surface gravity (log g)

4.840 dex

Stellar density

3.880 g/cm³

Systemic radial velocity

3.22 km/s

Rotation period

29.00 days

Activity index (log R'HK)

-4.768

Metallicity ratio

[Fe/H]

Distance
25.15 parsec
Light-years 82.03 ly
V-band magnitude
11.01 mag
Voyager-speed travel 1,446,545 yr

Multi-band Host Photometry — 15 bands

6.912.512.46B11.01V10.23Gaia9.23TESS11.75Sloan g10.42Sloan r9.68Sloan i9.06Ic7.94J7.32H7.08K6.93W16.98W26.91W36.90W4

Astrometric Data

Parallax

39.733 mas

Total Proper Motion

344.533 mas/yr

PM Right Ascension

-319.96 mas/yr

PM Declination

-127.78 mas/yr

Galactic Cartesian (pc)

x = 0.491 · y = -0.086 · z = -0.867

Equatorial (J2000)

RA 350.02859° · Dec -60.06573°

Galactic ℓ, b

321.956° · -53.559°

Ecliptic λ, β

319.212° · -49.528°

HTM-20 index

1337395039

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