Key parameters at a glance

A radius of 2.56 Earth radii
A mass of 8.82 Earth masses
Surface gravity around 1.34 g
An orbital period of 107.245 days
Semi-major axis 0.4250 AU
Equilibrium temperature 431 K (158 °C)
Distance from Earth 47.89 light-years
Earth Similarity Index 0.574
Travel time at Voyager 1 speed 844,474 years

2 siblings around HD 136352

HD 136352 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
HD 136352 b	Super-Earth	1.66	4.72	11.578	905	2019
HD 136352 c	Sub-Neptune	2.92	11.24	27.592	677	2019
HD 136352 d this	Sub-Neptune	2.56	8.82	107.245	431	2019

HD 136352 d Planet Profile

Physical Specs

Radius

2.56 R⊕

Radius (Jupiter)

0.229 R♃

Mass

8.82 M⊕

Mass (Jupiter)

0.028 M♃

Density

2.88 g/cm³

Surface Gravity

1.34 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.574

HZ Position Inner

Controversial No

Discovery

Year 2019

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#1090of 1978

top 55.1%

This planet

2.56R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-1174 b 2.56 R⊕ Kepler-171 c 2.56 R⊕ Kepler-175 b 2.56 R⊕

Metric	Earth	HD 136352 d	Jupiter
Radius (R⊕)	1.00	2.56	11.21
Mass (M⊕)	1.00	8.82	317.83
Density (g/cm³)	5.51	2.88	1.33
Surface Gravity (g)	1.00	1.34	2.53
Insolation (S⊕)	1.00	5.74	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	8.820 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	10.500 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 136352

HIP

HIP 75181

TIC

TIC 136916387

Gaia DR2

Gaia DR2 5902750168276592256

Gaia DR3

Gaia DR3 5902750168276592256

System

HD 136352

Percentile among Sub-Neptune cohort

Radius 2.562 R⊕ · percentile 45 / cohort 1978

Mass 8.820 M⊕ · percentile 63 / cohort 1978

Orbital period 107.25 d · percentile 95 / cohort 1946

Distance 14.68 pc · percentile 3 / cohort 1975

ESI 0.574 · percentile 80 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

107.245 days

Semi-major axis

0.4250 AU

Eccentricity

0.000

Inclination

89.73 °

Year Length

A year here lasts approximately 107.25 Earth days (29.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.4250 AU.

Transit Fingerprint

Depth

0.049 %

Duration

8.870 h

Impact parameter b

0.410

Rp / R★

0.022190

Transit midpoint (BJD)

2,459,009.7759

Photometric dip

Transit produces a flux drop of 492 ppm lasting ≈ 8.87 h.

Extended Orbital Architecture

Planet / star radius ratio

0.022190

Semi-major axis / stellar radius

86.460

Impact parameter (b)

0.410

RV semi-amplitude (K)

1.300 m/s

Transit mid-time (BJD)

2,459,009.7759

Long. of periastron (ω)

170.89°

Angular separation (arcsec)

28.90000

Eq. Temperature

431K

(158 °C)

Insolation (S⊕)

5.74

Earth = 1.00

Earth Similarity (ESI)

0.574

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

Udry et al. 2019

Instrument

HARPS Spectrograph

Publication

2019-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2019 at La Silla Observatory (12 shown).

HD 20781 b · Rocky Terrestrial HD 20781 c · Sub-Neptune HD 21693 b · Sub-Neptune HD 45184 c · Sub-Neptune HD 134060 b · Sub-Neptune HD 31527 b · Sub-Neptune HD 20781 d · Sub-Neptune HD 20003 b · Sub-Neptune HD 31527 d · Sub-Neptune HD 45184 b · Sub-Neptune HD 51608 b · Sub-Neptune HD 20781 e · Sub-Neptune

Host System: HD 136352

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,664 K — cooler than the Sun (5,778 K)

Estimated Age

12.30 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.058 R☉

Stellar Mass

0.870 M☉

Metallicity [Fe/H]

-0.24

Extended Stellar Properties

Surface gravity (log g)

4.390 dex

Stellar density

1.035 g/cm³

Systemic radial velocity

-69.00 km/s

Rotational v·sin i

1.00 km/s

Rotation period

23.80 days

Activity index (log R'HK)

-4.910

Metallicity ratio

[M/H]

Distance

14.68 parsec

Light-years 47.89 ly

V-band magnitude

5.65 mag

Voyager-speed travel 844,474 yr

Multi-band Host Photometry — 8 bands

Astrometric Data

Parallax

68.082 mas

Total Proper Motion

1,647.340 mas/yr

PM Right Ascension

-1,624.05 mas/yr

PM Declination

-276.02 mas/yr

Galactic Cartesian (pc)

x = -0.424 · y = -0.513 · z = -0.747

Equatorial (J2000)

RA 230.44011° · Dec -48.31882°

Galactic ℓ, b

327.071° · 7.381°

Ecliptic λ, β

241.104° · -28.770°

HTM-20 index

1294898941

Observation Record

Photometric series

RV measurements

Stellar spectra