Key parameters at a glance

A radius of 2.61 Earth radii
A mass of 26.57 Earth masses
Surface gravity around 3.91 g
An orbital period of 47.425 days
Semi-major axis 0.2958 AU
Equilibrium temperature 546 K (273 °C)
Distance from Earth 204.76 light-years
Earth Similarity Index 0.434
Travel time at Voyager 1 speed 3,610,909 years

2 siblings around HD 22946

HD 22946 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
TOI-411 b	Super-Earth	1.36	13.71	4.040	1,241	2022
TOI-411 c	Sub-Neptune	2.33	9.72	9.573	931	2022
HD 22946 d this	Sub-Neptune	2.61	26.57	47.425	546	2023

HD 22946 d Planet Profile

Physical Specs

Radius

2.61 R⊕

Radius (Jupiter)

0.233 R♃

Mass

26.57 M⊕

Mass (Jupiter)

0.084 M♃

Density

10.80 g/cm³

Surface Gravity

3.91 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.434

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

#1012of 1978

top 51.1%

This planet

2.61R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

HD 110067 g 2.61 R⊕ Kepler-20 d 2.61 R⊕ K2-207 b 2.61 R⊕

Metric	Earth	HD 22946 d	Jupiter
Radius (R⊕)	1.00	2.61	11.21
Mass (M⊕)	1.00	26.57	317.83
Density (g/cm³)	5.51	10.80	1.33
Surface Gravity (g)	1.00	3.91	2.53
Insolation (S⊕)	1.00	18.56	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	26.570 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 22946

HIP

HIP 17047

TIC

TIC 100990000

Gaia DR2

Gaia DR2 4848767461548943104

Gaia DR3

Gaia DR3 4848767461548943104

System

HD 22946

Percentile among Sub-Neptune cohort

Radius 2.607 R⊕ · percentile 49 / cohort 1978

Mass 26.570 M⊕ · percentile 96 / cohort 1978

Orbital period 47.42 d · percentile 84 / cohort 1946

Distance 62.78 pc · percentile 14 / cohort 1975

ESI 0.434 · percentile 59 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

47.425 days

Semi-major axis

0.2958 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 47.42 Earth days (13.0% of a terrestrial year) at a mean orbital distance of 0.2958 AU.

Transit Fingerprint

Duration

6.482 h

Impact parameter b

0.456

Rp / R★

0.021410

Transit midpoint (BJD)

2,459,136.5372

Extended Orbital Architecture

Planet / star radius ratio

0.021410

Semi-major axis / stellar radius

57.000

Impact parameter (b)

0.456

RV semi-amplitude (K)

4.310 m/s

Transit mid-time (BJD)

2,459,136.5372

Angular separation (arcsec)

4.71000

Eq. Temperature

546K

(273 °C)

Insolation (S⊕)

18.56

Earth = 1.00

Earth Similarity (ESI)

0.434

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Garai et al. 2023

Instrument

TESS CCD Array

Publication

2023-06

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: HD 22946

Spectral Class

F-type yellow-white

Effective Temperature

6,169 K — hotter than the Sun (5,778 K)

Estimated Age

2.50 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.117 R☉

Stellar Mass

1.098 M☉

Metallicity [Fe/H]

-0.08

Extended Stellar Properties

Surface gravity (log g)

4.470 dex

Stellar density

1.100 g/cm³

Metallicity ratio

[Fe/H]

Distance

62.78 parsec

Light-years 204.76 ly

V-band magnitude

8.27 mag

Voyager-speed travel 3,610,909 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

15.900 mas

Total Proper Motion

122.096 mas/yr

PM Right Ascension

-51.66 mas/yr

PM Declination

-110.63 mas/yr

Galactic Cartesian (pc)

x = 0.423 · y = 0.600 · z = -0.679

Equatorial (J2000)

RA 54.81954° · Dec -42.76303°

Galactic ℓ, b

248.832° · -52.700°

Ecliptic λ, β

33.543° · -59.500°

HTM-20 index

488407113