Key parameters at a glance

A radius of 2.35 Earth radii
A mass of 4.80 Earth masses
Surface gravity around 0.87 g
An orbital period of 10.689 days
Semi-major axis 0.0804 AU
Equilibrium temperature 514 K (241 °C)
Distance from Earth 200.65 light-years
Earth Similarity Index 0.479
Travel time at Voyager 1 speed 3,538,506 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

TOI-4342 is a red dwarf star in the constellation Octans located 201 light-years from Earth. It hosts two transiting exoplanets. Both planets are considered to be good targets for transmission spectroscopy measurements for determination of atmospheric composition.

Excerpted from Wikipedia · full article

1 sibling around TOI-4342

TOI-4342 c 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
TOI-4342 b	Sub-Neptune	2.33	7.30	5.538	639	2023
TOI-4342 c this	Sub-Neptune	2.35	4.80	10.689	514	2023

TOI-4342 c Planet Profile

Physical Specs

Radius

2.35 R⊕

Radius (Jupiter)

0.210 R♃

Mass

4.80 M⊕

Mass (Jupiter)

0.015 M♃

Density

2.01 g/cm³

Surface Gravity

0.87 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.479

HZ Position Inner

Controversial No

Discovery

Year 2023

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#1426of 1978

top 72.0%

This planet

2.35R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-24 b 2.35 R⊕ Kepler-306 c 2.35 R⊕ Kepler-216 b 2.35 R⊕

Metric	Earth	TOI-4342 c	Jupiter
Radius (R⊕)	1.00	2.35	11.21
Mass (M⊕)	1.00	4.80	317.83
Density (g/cm³)	5.51	2.01	1.33
Surface Gravity (g)	1.00	0.87	2.53
Insolation (S⊕)	1.00	11.60	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	4.800 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 354944123

Gaia DR2

Gaia DR2 6355915466180482944

Gaia DR3

Gaia DR3 6355915466181029376

System

TOI-4342

Percentile among Sub-Neptune cohort

Radius 2.349 R⊕ · percentile 28 / cohort 1978

Mass 4.800 M⊕ · percentile 5 / cohort 1978

Orbital period 10.69 d · percentile 37 / cohort 1946

Distance 61.52 pc · percentile 14 / cohort 1975

ESI 0.479 · percentile 68 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

10.689 days

Semi-major axis

0.0804 AU

Eccentricity

0.000

Inclination

89.61 °

Year Length

A year here lasts approximately 10.69 Earth days (2.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0804 AU.

Transit Fingerprint

Depth

0.150 %

Duration

2.854 h

Impact parameter b

0.200

Rp / R★

0.036020

Transit midpoint (BJD)

2,458,659.3486

Photometric dip

Transit produces a flux drop of 1,501 ppm lasting ≈ 2.85 h.

Extended Orbital Architecture

Planet / star radius ratio

0.036020

Semi-major axis / stellar radius

29.400

Impact parameter (b)

0.200

RV semi-amplitude (K)

1.970 m/s

Transit mid-time (BJD)

2,458,659.3486

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

1.31000

Eq. Temperature

514K

(241 °C)

Insolation (S⊕)

11.60

Earth = 1.00

Earth Similarity (ESI)

0.479

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

Tey et al. 2023

Instrument

TESS CCD Array

Publication

2023-01

Observation locale

Space

Discovery cohort

Planets confirmed in 2023 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-700 e · Rocky Terrestrial TOI-2095 c · Super-Earth TOI-715 b · Super-Earth TOI-2095 b · Super-Earth TOI-2096 c · Super-Earth TOI-1680 b · Super-Earth TOI-2096 b · Rocky Terrestrial TOI-904 c · Sub-Neptune TOI-1470 c · Sub-Neptune TOI-198 b · Super-Earth TOI-244 b · Super-Earth TOI-4184 b · Sub-Neptune

Host System: TOI-4342

Spectral Class

M-type red dwarf

Effective Temperature

3,866 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.598 R☉

Stellar Mass

0.587 M☉

Metallicity [Fe/H]

0.26

Extended Stellar Properties

Surface gravity (log g)

4.652 dex

Stellar density

3.860 g/cm³

Systemic radial velocity

-4.43 km/s

Rotation period

14.69 days

Metallicity ratio

[Fe/H]

Distance

61.52 parsec

Light-years 200.65 ly

V-band magnitude

12.67 mag

Voyager-speed travel 3,538,506 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

16.226 mas

Total Proper Motion

151.177 mas/yr

PM Right Ascension

120.40 mas/yr

PM Declination

-91.43 mas/yr

Galactic Cartesian (pc)

x = 0.169 · y = -0.121 · z = -0.978

Equatorial (J2000)

RA 324.38942° · Dec -77.97915°

Galactic ℓ, b

313.860° · -34.672°

Ecliptic λ, β

288.693° · -58.117°

HTM-20 index

2076464689

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