Key parameters at a glance

A radius of 9.57 Earth radii
A mass of 66.50 Earth masses
Surface gravity around 0.73 g
An orbital period of 27.364 days
Semi-major axis 0.0886 AU
Equilibrium temperature 244 K (-29 °C)
Distance from Earth 328.25 light-years
Earth Similarity Index 0.372
Travel time at Voyager 1 speed 5,788,630 years
Almost certainly tidally locked to its host star given the close orbit

TOI-1227 b Planet Profile

Physical Specs

Radius

9.57 R⊕

Radius (Jupiter)

0.854 R♃

Mass

66.50 M⊕

Mass (Jupiter)

0.209 M♃

Density

0.42 g/cm³

Surface Gravity

0.73 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.372

HZ Position Inner

Controversial No

Discovery

Year 2022

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#39of 574

top 6.6%

This planet

9.57R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

HD 8326 b 9.58 R⊕ TOI-6894 b 9.58 R⊕ TOI-954 b 9.55 R⊕

Metric	Earth	TOI-1227 b	Jupiter
Radius (R⊕)	1.00	9.57	11.21
Mass (M⊕)	1.00	66.50	317.83
Density (g/cm³)	5.51	0.42	1.33
Surface Gravity (g)	1.00	0.73	2.53
Insolation (S⊕)	1.00	3.21	0.037

Star Catalogue Identifiers

TIC

TIC 360156606

Gaia DR2

Gaia DR2 5842480953772012928

Gaia DR3

Gaia DR3 5842480953772012928

System

TOI-1227

Percentile among Neptune-like cohort

Radius 9.572 R⊕ · percentile 93 / cohort 574

Mass 66.500 M⊕ · percentile 82 / cohort 574

Orbital period 27.36 d · percentile 58 / cohort 524

Distance 100.64 pc · percentile 24 / cohort 572

ESI 0.372 · percentile 68 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

27.364 days

Semi-major axis

0.0886 AU

Eccentricity

—

Inclination

88.57 °

Year Length

A year here lasts approximately 27.36 Earth days (7.5% of a terrestrial year) at a mean orbital distance of 0.0886 AU.

Transit Fingerprint

Depth

2.069 %

Duration

4.831 h

Impact parameter b

0.849

Rp / R★

0.156800

Transit midpoint (BJD)

2,458,617.4621

Photometric dip

Transit produces a flux drop of 20,691 ppm lasting ≈ 4.83 h.

Extended Orbital Architecture

Planet / star radius ratio

0.156800

Semi-major axis / stellar radius

34.010

Impact parameter (b)

0.849

Transit mid-time (BJD)

2,458,617.4621

Angular separation (arcsec)

0.88000

Eq. Temperature

244K

(-29 °C)

Insolation (S⊕)

3.21

Earth = 1.00

Earth Similarity (ESI)

0.372

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — surface water would be frozen. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Mann et al. 2022

Instrument

TESS CCD Array

Publication

2022-04

Observation locale

Space

Discovery cohort

Planets confirmed in 2022 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-1452 b · Super-Earth TOI-712 d · Sub-Neptune TOI-1468 c · Sub-Neptune TOI-2136 b · Sub-Neptune LTT 1445 A c · Rocky Terrestrial TOI-712 c · Sub-Neptune LP 890-9 b · Super-Earth TOI-2081 b · Sub-Neptune GJ 3929 b · Rocky Terrestrial HD 260655 c · Super-Earth HD 73583 c · Sub-Neptune TOI-1759 b · Sub-Neptune

Host System: TOI-1227

Spectral Class

M-type red dwarf

Effective Temperature

3,072 K — cooler than the Sun (5,778 K)

Estimated Age

0.01 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.560 R☉

Stellar Mass

0.170 M☉

Metallicity [Fe/H]

—

Extended Stellar Properties

Surface gravity (log g)

4.438 dex

Stellar density

1.325 g/cm³

Systemic radial velocity

13.30 km/s

Rotational v·sin i

16.65 km/s

Rotation period

1.65 days

Distance

100.64 parsec

Light-years 328.25 ly

V-band magnitude

17.00 mag

Voyager-speed travel 5,788,630 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

9.908 mas

Total Proper Motion

41.648 mas/yr

PM Right Ascension

-40.27 mas/yr

PM Declination

-10.64 mas/yr

Galactic Cartesian (pc)

x = -0.299 · y = -0.036 · z = -0.953

Equatorial (J2000)

RA 186.76736° · Dec -72.45185°

Galactic ℓ, b

301.072° · -9.668°

Ecliptic λ, β

233.981° · -59.390°

HTM-20 index

1595658751