Key parameters at a glance

A radius of 13.60 Earth radii
A mass of 459.58 Earth masses
Surface gravity around 2.48 g
An orbital period of 7.127 days
Semi-major axis 0.0736 AU
Distance from Earth 65.43 light-years
Earth Similarity Index 0.338
Travel time at Voyager 1 speed 1,153,912 years

1 sibling around HD 217107

HD 217107 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HD 217107 b this	Gas Giant	13.60	459.58	7.127	—	1998
HD 217107 c	Gas Giant	12.90	1,388.91	5,138.700	—	2005

HD 217107 b Planet Profile

Physical Specs

Radius

13.60 R⊕

Radius (Jupiter)

1.210 R♃

Mass

459.58 M⊕

Mass (Jupiter)

1.446 M♃

Density

1.00 g/cm³

Surface Gravity

2.48 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.338

HZ Position Unknown

Controversial No

Discovery

Year 1998

Method Radial Velocity

Facility Lick Observatory

Telescope 3.0 m C. Donald Shane 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 217107 b	Jupiter
Radius (R⊕)	1.00	13.60	11.21
Mass (M⊕)	1.00	459.58	317.83
Density (g/cm³)	5.51	1.00	1.33
Surface Gravity (g)	1.00	2.48	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	459.580 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	449.234 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 217107

HIP

HIP 113421

TIC

TIC 38271828

Gaia DR2

Gaia DR2 2648914040357320576

Gaia DR3

Gaia DR3 2648914040357320576

System

HD 217107

Percentile among Gas Giant cohort

Radius 13.600 R⊕ · percentile 63 / cohort 1771

Mass 459.580 M⊕ · percentile 46 / cohort 1747

Orbital period 7.13 d · percentile 41 / cohort 1533

Distance 20.06 pc · percentile 4 / cohort 1759

ESI 0.338 · percentile 67 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

7.127 days

Semi-major axis

0.0736 AU

Eccentricity

0.128

Inclination

93.00 °

Year Length

A year here lasts approximately 7.13 Earth days (2.0% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0736 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

141.910 m/s

Transit mid-time (BJD)

2,456,306.8470

Long. of periastron (ω)

22.78°

Angular separation (arcsec)

3.67000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.338

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Fischer et al. 1999

Instrument

Hamilton Echelle Spectrograph

Publication

1999-01

Observation locale

Ground

Host System: HD 217107

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,622 K — cooler than the Sun (5,778 K)

Estimated Age

11.90 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.225 R☉

Stellar Mass

1.045 M☉

Metallicity [Fe/H]

0.37

Extended Stellar Properties

Surface gravity (log g)

4.340 dex

Stellar density

0.801 g/cm³

Systemic radial velocity

-13.14 km/s

Rotational v·sin i

0.00 km/s

Activity index (log R'HK)

-5.080

Metallicity ratio

[Fe/H]

Distance

20.06 parsec

Light-years 65.43 ly

V-band magnitude

6.16 mag

Voyager-speed travel 1,153,912 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

49.817 mas

Total Proper Motion

16.398 mas/yr

PM Right Ascension

-7.11 mas/yr

PM Declination

-14.78 mas/yr

Galactic Cartesian (pc)

x = 0.963 · y = -0.266 · z = -0.042

Equatorial (J2000)

RA 344.56472° · Dec -2.39545°

Galactic ℓ, b

70.474° · -53.324°

Ecliptic λ, β

344.855° · 3.866°

HTM-20 index

1794766806

Observation Record

Photometric series

RV measurements

Stellar spectra

Archive notes