Key parameters at a glance

A radius of 13.60 Earth radii
A mass of 476.72 Earth masses
Surface gravity around 2.58 g
An orbital period of 461.200 days
Semi-major axis 1.2030 AU
Distance from Earth 165.27 light-years
Earth Similarity Index 0.341
Travel time at Voyager 1 speed 2,914,452 years

HD 188015 b Planet Profile

Physical Specs

Radius

13.60 R⊕

Radius (Jupiter)

1.210 R♃

Mass

476.72 M⊕

Mass (Jupiter)

1.500 M♃

Density

1.04 g/cm³

Surface Gravity

2.58 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.341

HZ Position Unknown

Controversial No

Discovery

Year 2004

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#609of 1771

top 34.3%

This planet

13.60R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 19994 b 13.60 R⊕ HD 205739 b 13.60 R⊕ HD 79498 b 13.60 R⊕

Metric	Earth	HD 188015 b	Jupiter
Radius (R⊕)	1.00	13.60	11.21
Mass (M⊕)	1.00	476.72	317.83
Density (g/cm³)	5.51	1.04	1.33
Surface Gravity (g)	1.00	2.58	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	476.720 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 188015

HIP

HIP 97769

TIC

TIC 11499710

Gaia DR2

Gaia DR2 2028419118720795392

Gaia DR3

Gaia DR3 2028419118720795392

System

HD 188015

Percentile among Gas Giant cohort

Radius 13.600 R⊕ · percentile 63 / cohort 1771

Mass 476.720 M⊕ · percentile 47 / cohort 1747

Orbital period 461.20 d · percentile 66 / cohort 1533

Distance 50.67 pc · percentile 20 / cohort 1759

ESI 0.341 · percentile 68 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

461.200 days

Semi-major axis

1.2030 AU

Eccentricity

0.137

Inclination

— °

Year Length

A year here lasts about 1.26 Earth years on a mildly elliptical path at a mean orbital distance of 1.2030 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

37.600 m/s

Transit mid-time (BJD)

2,452,094.4000

Long. of periastron (ω)

222.00°

Angular separation (arcsec)

23.70000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.341

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Marcy et al. 2005

Instrument

HIRES Spectrometer

Publication

2005-01

Observation locale

Ground

Discovery cohort

Planets confirmed in 2004 at W. M. Keck Observatory (6 shown).

HD 99492 b · Neptune-like HD 183263 b · Gas Giant HD 117207 b · Gas Giant HD 45350 b · Gas Giant GJ 436 b · Neptune-like HD 88133 b · Gas Giant

Host System: HD 188015

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,746 K — cooler than the Sun (5,778 K)

Estimated Age

6.61 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.125 R☉

Stellar Mass

1.090 M☉

Metallicity [Fe/H]

0.29

Extended Stellar Properties

Surface gravity (log g)

4.445 dex

Stellar density

1.129 g/cm³

Systemic radial velocity

0.28 km/s

Rotational v·sin i

0.00 km/s

Activity index (log R'HK)

-5.050

Metallicity ratio

[Fe/H]

Distance

50.67 parsec

Light-years 165.27 ly

V-band magnitude

8.24 mag

Voyager-speed travel 2,914,452 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

19.707 mas

Total Proper Motion

105.890 mas/yr

PM Right Ascension

52.54 mas/yr

PM Declination

-91.93 mas/yr

Galactic Cartesian (pc)

x = 0.414 · y = -0.779 · z = 0.471

Equatorial (J2000)

RA 298.01919° · Dec 28.09998°

Galactic ℓ, b

64.560° · 0.542°

Ecliptic λ, β

308.169° · 47.894°

HTM-20 index

-533025311

Observation Record

Photometric series

RV measurements

Stellar spectra

Archive notes