Key parameters at a glance

A radius of 13.10 Earth radii
A mass of 982.05 Earth masses
Surface gravity around 5.72 g
An orbital period of 456.100 days
Semi-major axis 1.2500 AU
Distance from Earth 182.40 light-years
Earth Similarity Index 0.400
Travel time at Voyager 1 speed 3,216,563 years

HD 221287 b Planet Profile

Physical Specs

Radius

13.10 R⊕

Radius (Jupiter)

1.170 R♃

Mass

982.05 M⊕

Mass (Jupiter)

3.090 M♃

Density

2.40 g/cm³

Surface Gravity

5.72 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.400

HZ Position Unknown

Controversial No

Discovery

Year 2007

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#910of 1771

top 51.3%

This planet

13.10R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

GJ 3021 b 13.10 R⊕ 91 Aqr b 13.10 R⊕ HD 37605 c 13.10 R⊕

Metric	Earth	HD 221287 b	Jupiter
Radius (R⊕)	1.00	13.10	11.21
Mass (M⊕)	1.00	982.05	317.83
Density (g/cm³)	5.51	2.40	1.33
Surface Gravity (g)	1.00	5.72	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	982.050 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 221287

HIP

HIP 116084

TIC

TIC 231716612

Gaia DR2

Gaia DR2 6489603813690967808

Gaia DR3

Gaia DR3 6489603813690967808

System

HD 221287

Percentile among Gas Giant cohort

Radius 13.100 R⊕ · percentile 46 / cohort 1771

Mass 982.050 M⊕ · percentile 66 / cohort 1747

Orbital period 456.10 d · percentile 66 / cohort 1533

Distance 55.92 pc · percentile 23 / cohort 1759

ESI 0.400 · percentile 86 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

456.100 days

Semi-major axis

1.2500 AU

Eccentricity

0.080

Inclination

— °

Year Length

A year here lasts about 1.25 Earth years on a nearly circular orbit at a mean orbital distance of 1.2500 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.400

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Naef et al. 2007

Instrument

HARPS Spectrograph

Publication

2007-08

Observation locale

Ground

Discovery cohort

Planets confirmed in 2007 at La Silla Observatory (10 shown).

GJ 581 c · Sub-Neptune GJ 674 b · Sub-Neptune HD 219828 b · Neptune-like HD 70573 b · Gas Giant HD 171028 b · Gas Giant BD-13 2130 b · Gas Giant HD 156846 b · Gas Giant HD 190647 b · Gas Giant HD 4113 b · Gas Giant HD 100777 b · Gas Giant

Host System: HD 221287

Spectral Class

F-type yellow-white

Effective Temperature

6,304 K — hotter than the Sun (5,778 K)

Estimated Age

1.30 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.139 R☉

Stellar Mass

1.250 M☉

Metallicity [Fe/H]

-0.03

Extended Stellar Properties

Surface gravity (log g)

4.430 dex

Stellar density

1.213 g/cm³

Systemic radial velocity

-21.90 km/s

Rotational v·sin i

3.92 km/s

Metallicity ratio

[Fe/H]

Distance

55.92 parsec

Light-years 182.40 ly

V-band magnitude

7.82 mag

Voyager-speed travel 3,216,563 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

17.853 mas

Total Proper Motion

181.237 mas/yr

PM Right Ascension

181.16 mas/yr

PM Declination

-5.30 mas/yr

Galactic Cartesian (pc)

x = 0.523 · y = -0.066 · z = -0.850

Equatorial (J2000)

RA 352.83622° · Dec -58.20975°

Galactic ℓ, b

321.702° · -55.903°

Ecliptic λ, β

322.683° · -48.913°

HTM-20 index

-1862048831

Observation Record

Photometric series

RV measurements

Archive notes