Key parameters at a glance

A radius of 2.69 Earth radii
A mass of 15.54 Earth masses
Surface gravity around 2.14 g
An orbital period of 20.544 days
Semi-major axis 0.1460 AU
Equilibrium temperature 679 K (406 °C)
Distance from Earth 73.07 light-years
Earth Similarity Index 0.396
Travel time at Voyager 1 speed 1,288,596 years

2 siblings around HD 63433

HD 63433 c 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
HD 63433 d	Rocky Terrestrial	1.07	1.25	4.209	1,040	2023
HD 63433 b	Sub-Neptune	2.14	21.76	7.108	967	2020
HD 63433 c this	Sub-Neptune	2.69	15.54	20.544	679	2020

HD 63433 c Planet Profile

Physical Specs

Radius

2.69 R⊕

Radius (Jupiter)

0.240 R♃

Mass

15.54 M⊕

Mass (Jupiter)

0.049 M♃

Density

4.63 g/cm³

Surface Gravity

2.14 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.396

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

#879of 1978

top 44.4%

This planet

2.69R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-4504 b 2.69 R⊕ Kepler-417 c 2.69 R⊕ HD 28109 b 2.69 R⊕

Metric	Earth	HD 63433 c	Jupiter
Radius (R⊕)	1.00	2.69	11.21
Mass (M⊕)	1.00	15.54	317.83
Density (g/cm³)	5.51	4.63	1.33
Surface Gravity (g)	1.00	2.14	2.53
Insolation (S⊕)	1.00	35.36	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	15.539 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 63433

HIP

HIP 38228

TIC

TIC 130181866

Gaia DR2

Gaia DR2 875071278432954240

Gaia DR3

Gaia DR3 875071278432954240

System

HD 63433

Percentile among Sub-Neptune cohort

Radius 2.692 R⊕ · percentile 56 / cohort 1978

Mass 15.539 M⊕ · percentile 93 / cohort 1978

Orbital period 20.54 d · percentile 63 / cohort 1946

Distance 22.40 pc · percentile 5 / cohort 1975

ESI 0.396 · percentile 51 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

20.544 days

Semi-major axis

0.1460 AU

Eccentricity

0.210

Inclination

89.07 °

Year Length

A year here lasts approximately 20.54 Earth days (5.6% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1460 AU.

Transit Fingerprint

Depth

0.080 %

Duration

4.068 h

Impact parameter b

0.544

Rp / R★

0.026000

Transit midpoint (BJD)

2,458,844.0589

Photometric dip

Transit produces a flux drop of 799 ppm lasting ≈ 4.07 h.

Extended Orbital Architecture

Planet / star radius ratio

0.026000

Semi-major axis / stellar radius

33.479

Impact parameter (b)

0.544

RV semi-amplitude (K)

3.737 m/s

Transit mid-time (BJD)

2,458,844.0589

Long. of periastron (ω)

90.00°

Sky-projected obliquity (λ)

-1.00°

Angular separation (arcsec)

6.52000

Eq. Temperature

679K

(406 °C)

Insolation (S⊕)

35.36

Earth = 1.00

Earth Similarity (ESI)

0.396

0 = alien, 1 = Earth-identical

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

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

Mann et al. 2020

Instrument

TESS CCD Array

Publication

2020-10

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 63433

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,553 K — cooler than the Sun (5,778 K)

Estimated Age

0.41 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.934 R☉

Stellar Mass

0.956 M☉

Metallicity [Fe/H]

-0.07

Extended Stellar Properties

Surface gravity (log g)

4.560 dex

Stellar density

1.800 g/cm³

Systemic radial velocity

-15.81 km/s

Rotational v·sin i

7.26 km/s

Rotation period

6.40 days

Activity index (log R'HK)

-4.390

Metallicity ratio

[Fe/H]

Distance

22.40 parsec

Light-years 73.07 ly

V-band magnitude

6.92 mag

Voyager-speed travel 1,288,596 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

44.607 mas

Total Proper Motion

15.118 mas/yr

PM Right Ascension

-10.03 mas/yr

PM Declination

-11.31 mas/yr

Galactic Cartesian (pc)

x = -0.410 · y = 0.788 · z = 0.460

Equatorial (J2000)

RA 117.47937° · Dec 27.36313°

Galactic ℓ, b

193.282° · 24.147°

Ecliptic λ, β

114.341° · 6.217°

HTM-20 index

310887370