Key parameters at a glance

A radius of 3.31 Earth radii
A mass of 9.20 Earth masses
Surface gravity around 0.84 g
An orbital period of 3.348 days
Semi-major axis 0.0293 AU
Equilibrium temperature 531 K (258 °C)
Distance from Earth 154.42 light-years
Earth Similarity Index 0.410
Travel time at Voyager 1 speed 2,723,137 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around TOI-2015

TOI-2015 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
TOI-2015 b this	Sub-Neptune	3.31	9.20	3.348	531	2023
TOI-2015 c	Sub-Neptune	2.93	8.91	5.583	448	2025

TOI-2015 b Planet Profile

Physical Specs

Radius

3.31 R⊕

Radius (Jupiter)

0.295 R♃

Mass

9.20 M⊕

Mass (Jupiter)

0.029 M♃

Density

1.40 g/cm³

Surface Gravity

0.84 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.410

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

#277of 1978

top 14.0%

This planet

3.31R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-207 d 3.31 R⊕ Kepler-606 b 3.31 R⊕ DMPP-1 c 3.31 R⊕

Metric	Earth	TOI-2015 b	Jupiter
Radius (R⊕)	1.00	3.31	11.21
Mass (M⊕)	1.00	9.20	317.83
Density (g/cm³)	5.51	1.40	1.33
Surface Gravity (g)	1.00	0.84	2.53
Insolation (S⊕)	1.00	13.19	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	9.200 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 368287008

Gaia DR2

Gaia DR2 1270814787767025408

Gaia DR3

Gaia DR3 1270814787767025408

System

TOI-2015

Percentile among Sub-Neptune cohort

Radius 3.309 R⊕ · percentile 86 / cohort 1978

Mass 9.200 M⊕ · percentile 67 / cohort 1978

Orbital period 3.35 d · percentile 6 / cohort 1946

Distance 47.34 pc · percentile 11 / cohort 1975

ESI 0.410 · percentile 54 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

3.348 days

Semi-major axis

0.0293 AU

Eccentricity

0.079

Inclination

87.61 °

Year Length

A year here lasts approximately 3.35 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0293 AU.

Transit Fingerprint

Depth

0.870 %

Duration

0.988 h

Impact parameter b

0.744

Rp / R★

0.092780

Transit midpoint (BJD)

2,459,424.7857

Photometric dip

Transit produces a flux drop of 8,700 ppm lasting ≈ 0.99 h.

Extended Orbital Architecture

Planet / star radius ratio

0.092780

Semi-major axis / stellar radius

19.281

Impact parameter (b)

0.744

RV semi-amplitude (K)

14.400 m/s

Transit mid-time (BJD)

2,459,424.7857

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

0.61900

Eq. Temperature

531K

(258 °C)

Insolation (S⊕)

13.19

Earth = 1.00

Earth Similarity (ESI)

0.410

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.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Jones et al. 2023

Instrument

TESS CCD Array

Publication

2023-10

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-2015

Spectral Class

M-type red dwarf

Effective Temperature

3,297 K — cooler than the Sun (5,778 K)

Estimated Age

5.50 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.327 R☉

Stellar Mass

0.304 M☉

Metallicity [Fe/H]

-0.31

Extended Stellar Properties

Surface gravity (log g)

5.040 dex

Stellar density

11.800 g/cm³

Systemic radial velocity

-32.04 km/s

Rotational v·sin i

2.00 km/s

Rotation period

8.70 days

Metallicity ratio

[Fe/H]

Distance

47.34 parsec

Light-years 154.42 ly

V-band magnitude

16.11 mag

Voyager-speed travel 2,723,137 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

21.093 mas

Total Proper Motion

85.126 mas/yr

PM Right Ascension

-56.17 mas/yr

PM Declination

63.97 mas/yr

Galactic Cartesian (pc)

x = -0.545 · y = -0.701 · z = 0.460

Equatorial (J2000)

RA 232.13265° · Dec 27.36107°

Galactic ℓ, b

42.576° · 55.232°

Ecliptic λ, β

220.181° · 44.472°

HTM-20 index

1554128141