Key parameters at a glance

A radius of 13.50 Earth radii
A mass of 524.42 Earth masses
Surface gravity around 2.88 g
An orbital period of 93.310 days
Semi-major axis 0.4620 AU
Distance from Earth 530.17 light-years
Earth Similarity Index 0.350
Travel time at Voyager 1 speed 9,349,602 years

8 UMi b Planet Profile

Physical Specs

Radius

13.50 R⊕

Radius (Jupiter)

1.200 R♃

Mass

524.42 M⊕

Mass (Jupiter)

1.650 M♃

Density

1.17 g/cm³

Surface Gravity

2.88 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.350

HZ Position Unknown

Controversial No

Discovery

Year 2015

Method Radial Velocity

Facility Bohyunsan Optical Astronomical Observatory

Telescope 1.8 m Telescope

Size rank in cohort

Rank by radius

#671of 1771

top 37.8%

This planet

13.50R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 45350 b 13.50 R⊕ HD 82943 b 13.50 R⊕ HD 27442 b 13.50 R⊕

Metric	Earth	8 UMi b	Jupiter
Radius (R⊕)	1.00	13.50	11.21
Mass (M⊕)	1.00	524.42	317.83
Density (g/cm³)	5.51	1.17	1.33
Surface Gravity (g)	1.00	2.88	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	524.417 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 133086

HIP

HIP 73136

TIC

TIC 257005016

Gaia DR2

Gaia DR2 1700658653802527104

Gaia DR3

Gaia DR3 1700658653802527104

System

8 UMi

Percentile among Gas Giant cohort

Radius 13.500 R⊕ · percentile 59 / cohort 1771

Mass 524.417 M⊕ · percentile 50 / cohort 1747

Orbital period 93.31 d · percentile 53 / cohort 1533

Distance 162.55 pc · percentile 46 / cohort 1759

ESI 0.350 · percentile 71 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

93.310 days

Semi-major axis

0.4620 AU

Eccentricity

0.062

Inclination

— °

Year Length

A year here lasts approximately 93.31 Earth days (25.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.4620 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.350

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Lee et al. 2015

Instrument

BOES Echelle Spectrograph

Publication

2015-12

Observation locale

Ground

Discovery cohort

Planets confirmed in 2015 at Bohyunsan Optical Astronomical Observatory (3 shown).

HD 11755 b · Gas Giant HD 12648 b · Gas Giant HD 24064 b · Gas Giant

Host System: 8 UMi

Spectral Class

K-type orange

Effective Temperature

4,847 K — cooler than the Sun (5,778 K)

Estimated Age

1.70 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

10.730 R☉

Stellar Mass

1.510 M☉

Metallicity [Fe/H]

-0.03

Extended Stellar Properties

Surface gravity (log g)

2.570 dex

Systemic radial velocity

-9.20 km/s

Rotational v·sin i

3.60 km/s

Metallicity ratio

[m/H]

Distance

162.55 parsec

Light-years 530.17 ly

V-band magnitude

6.83 mag

Voyager-speed travel 9,349,602 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

6.123 mas

Total Proper Motion

13.284 mas/yr

PM Right Ascension

12.79 mas/yr

PM Declination

3.57 mas/yr

Galactic Cartesian (pc)

x = -0.187 · y = -0.182 · z = 0.965

Equatorial (J2000)

RA 224.20169° · Dec 74.90094°

Galactic ℓ, b

112.795° · 39.661°

Ecliptic λ, β

130.655° · 73.345°

HTM-20 index

893950861

Similar Worlds

Kepler-46 c

Gas Giant · K-type orange

Radius 13.50 R⊕ · 2,534.4 ly

HD 222076 b

Gas Giant · K-type orange

Radius 13.50 R⊕ · 297.3 ly

HD 128311 b

Gas Giant · K-type orange

Radius 13.50 R⊕ · 53.3 ly

BD+48 740 b

Gas Giant · K-type orange

Radius 13.50 R⊕ · 2,174.1 ly

HD 81688 b

Gas Giant · K-type orange

Radius 13.50 R⊕ · 279.6 ly

HD 47366 c

Gas Giant · K-type orange

Radius 13.50 R⊕ · 275.1 ly

Explore Related Categories

Gas Giant Planets Radial Velocity Discoveries Bohyunsan Optical Astronomical Observatory Mission K-type orange Hosts