Key parameters at a glance

A radius of 2.16 Earth radii
A mass of 7.25 Earth masses
Surface gravity around 1.55 g
An orbital period of 3.984 days
Semi-major axis 0.0490 AU
Equilibrium temperature 1,311 K (1038 °C)
Distance from Earth 149.00 light-years
Earth Similarity Index 0.202
Travel time at Voyager 1 speed 2,627,577 years

1 sibling around HD 86226

HD 86226 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
HD 86226 c this	Sub-Neptune	2.16	7.25	3.984	1,311	2020
HD 86226 b	Gas Giant	14.30	143.02	1,628.000	176	2009

HD 86226 c Planet Profile

Physical Specs

Radius

2.16 R⊕

Radius (Jupiter)

0.193 R♃

Mass

7.25 M⊕

Mass (Jupiter)

0.023 M♃

Density

3.97 g/cm³

Surface Gravity

1.55 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.202

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

#1731of 1978

top 87.5%

This planet

2.16R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-291 b 2.16 R⊕ Kepler-142 d 2.16 R⊕ Kepler-308 c 2.16 R⊕

Metric	Earth	HD 86226 c	Jupiter
Radius (R⊕)	1.00	2.16	11.21
Mass (M⊕)	1.00	7.25	317.83
Density (g/cm³)	5.51	3.97	1.33
Surface Gravity (g)	1.00	1.55	2.53
Insolation (S⊕)	1.00	647.90	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	7.250 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	7.450 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 86226

HIP

HIP 48739

TIC

TIC 22221375

Gaia DR2

Gaia DR2 5660492297395345408

Gaia DR3

Gaia DR3 5660492297395345408

System

HD 86226

Percentile among Sub-Neptune cohort

Radius 2.160 R⊕ · percentile 12 / cohort 1978

Mass 7.250 M⊕ · percentile 44 / cohort 1978

Orbital period 3.98 d · percentile 8 / cohort 1946

Distance 45.68 pc · percentile 11 / cohort 1975

ESI 0.202 · percentile 7 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

3.984 days

Semi-major axis

0.0490 AU

Eccentricity

0.075

Inclination

86.45 °

Year Length

A year here lasts approximately 3.98 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0490 AU.

Transit Fingerprint

Depth

0.045 %

Duration

3.120 h

Impact parameter b

0.630

Rp / R★

0.018800

Transit midpoint (BJD)

2,458,543.2539

Photometric dip

Transit produces a flux drop of 445 ppm lasting ≈ 3.12 h.

Extended Orbital Architecture

Planet / star radius ratio

0.018800

Semi-major axis / stellar radius

10.110

Impact parameter (b)

0.630

RV semi-amplitude (K)

2.890 m/s

Transit mid-time (BJD)

2,458,543.2539

Long. of periastron (ω)

196.00°

Angular separation (arcsec)

1.07000

Eq. Temperature

1,311K

(1038 °C)

Insolation (S⊕)

647.90

Earth = 1.00

Earth Similarity (ESI)

0.202

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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

Teske et al. 2020

Instrument

TESS CCD Array

Publication

2020-08

Observation locale

Space

Discovery cohort

Planets confirmed in 2020 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-700 d · Rocky Terrestrial TOI-237 b · Super-Earth TOI-700 b · Rocky Terrestrial TOI-1266 c · Super-Earth LTT 3780 c · Sub-Neptune TOI-700 c · Sub-Neptune TOI-776 c · Sub-Neptune TOI-942 c · Neptune-like TOI-776 b · Super-Earth TOI-1266 b · Sub-Neptune TOI-540 b · Rocky Terrestrial LHS 1815 b · Rocky Terrestrial

Host System: HD 86226

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,863 K — hotter than the Sun (5,778 K)

Estimated Age

4.60 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.053 R☉

Stellar Mass

1.019 M☉

Metallicity [Fe/H]

0.02

Extended Stellar Properties

Surface gravity (log g)

4.400 dex

Stellar density

1.233 g/cm³

Systemic radial velocity

19.78 km/s

Rotational v·sin i

2.40 km/s

Rotation period

22.80 days

Activity index (log R'HK)

-4.946

Metallicity ratio

[Fe/H]

Distance

45.68 parsec

Light-years 149.00 ly

V-band magnitude

7.93 mag

Voyager-speed travel 2,627,577 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

21.861 mas

Total Proper Motion

183.207 mas/yr

PM Right Ascension

-177.11 mas/yr

PM Declination

46.87 mas/yr

Galactic Cartesian (pc)

x = -0.783 · y = 0.468 · z = -0.408

Equatorial (J2000)

RA 149.12352° · Dec -24.09919°

Galactic ℓ, b

259.394° · 23.629°

Ecliptic λ, β

161.152° · -34.123°

HTM-20 index

-779098379