Key parameters at a glance

A radius of 2.18 Earth radii
A mass of 5.41 Earth masses
Surface gravity around 1.14 g
An orbital period of 5.198 days
Distance from Earth 88.22 light-years
Earth Similarity Index 0.754
Travel time at Voyager 1 speed 1,555,840 years

Context from the literature

HD 158259 is a main sequence star located 88 light-years away in the northern constellation of Draco. It hosts a system of at least five planets, discovered by the SOPHIE échelle spectrograph using the radial velocity method.

Excerpted from Wikipedia · full article

4 siblings around HD 158259

HD 158259 d shares its host star with 4 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HD 158259 b	Super-Earth	1.28	2.22	2.178	1,462	2020
HD 158259 c	Sub-Neptune	2.23	5.60	3.432	—	2020
HD 158259 d this	Sub-Neptune	2.18	5.41	5.198	—	2020
HD 158259 e	Sub-Neptune	2.34	6.08	7.951	—	2020
HD 158259 f	Sub-Neptune	2.35	6.14	12.028	—	2020

HD 158259 d Planet Profile

Physical Specs

Radius

2.18 R⊕

Radius (Jupiter)

0.195 R♃

Mass

5.41 M⊕

Mass (Jupiter)

0.017 M♃

Density

2.87 g/cm³

Surface Gravity

1.14 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.754

HZ Position Unknown

Controversial No

Discovery

Year 2020

Method Radial Velocity

Facility Haute-Provence Observatory

Telescope 1.93 m Telescope

Size rank in cohort

Rank by radius

#1703of 1978

top 86.0%

This planet

2.18R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

GJ 3090 b 2.18 R⊕ Kepler-261 b 2.18 R⊕ Kepler-250 d 2.18 R⊕

Metric	Earth	HD 158259 d	Jupiter
Radius (R⊕)	1.00	2.18	11.21
Mass (M⊕)	1.00	5.41	317.83
Density (g/cm³)	5.51	2.87	1.33
Surface Gravity (g)	1.00	1.14	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	5.410 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 158259

HIP

HIP 85268

TIC

TIC 188768068

Gaia DR2

Gaia DR2 1416050859226670848

Gaia DR3

Gaia DR3 1416050859226670848

System

HD 158259

Percentile among Sub-Neptune cohort

Radius 2.180 R⊕ · percentile 13 / cohort 1978

Mass 5.410 M⊕ · percentile 15 / cohort 1978

Orbital period 5.20 d · percentile 13 / cohort 1946

Distance 27.05 pc · percentile 7 / cohort 1975

ESI 0.754 · percentile 97 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

5.198 days

Semi-major axis

— AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 5.20 Earth days (1.4% of a terrestrial year).

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.754

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Hara et al. 2020

Instrument

SOPHIE Spectrograph

Publication

2020-04

Observation locale

Ground

Discovery cohort

Planets confirmed in 2020 at Haute-Provence Observatory (6 shown).

HD 158259 c · Sub-Neptune HD 158259 e · Sub-Neptune HD 158259 f · Sub-Neptune HD 113337 c · Gas Giant HD 158259 b · Super-Earth WASP-148 c · Gas Giant

Host System: HD 158259

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,802 K — hotter than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.210 R☉

Stellar Mass

1.080 M☉

Metallicity [Fe/H]

—

Extended Stellar Properties

Surface gravity (log g)

4.251 dex

Stellar density

0.725 g/cm³

Systemic radial velocity

13.30 km/s

Rotational v·sin i

2.90 km/s

Rotation period

20.00 days

Distance

27.05 parsec

Light-years 88.22 ly

V-band magnitude

6.48 mag

Voyager-speed travel 1,555,840 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

36.940 mas

Total Proper Motion

103.699 mas/yr

PM Right Ascension

-91.05 mas/yr

PM Declination

-49.64 mas/yr

Galactic Cartesian (pc)

x = -0.091 · y = -0.598 · z = 0.796

Equatorial (J2000)

RA 261.34958° · Dec 52.79047°

Galactic ℓ, b

80.138° · 34.090°

Ecliptic λ, β

248.565° · 75.586°

HTM-20 index

1025354342

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