Key parameters at a glance

A radius of 13.20 Earth radii
A mass of 832.71 Earth masses
Surface gravity around 4.78 g
An orbital period of 550.000 days
Semi-major axis 1.3200 AU
Distance from Earth 364.18 light-years
Earth Similarity Index 0.388
Travel time at Voyager 1 speed 6,422,359 years

HD 171028 b Planet Profile

Physical Specs

Radius

13.20 R⊕

Radius (Jupiter)

1.180 R♃

Mass

832.71 M⊕

Mass (Jupiter)

2.620 M♃

Density

1.99 g/cm³

Surface Gravity

4.78 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.388

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

#847of 1771

top 47.8%

This planet

13.20R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 12661 c 13.20 R⊕ HD 37605 b 13.20 R⊕ MOA-2009-BLG-387L b 13.20 R⊕

Metric	Earth	HD 171028 b	Jupiter
Radius (R⊕)	1.00	13.20	11.21
Mass (M⊕)	1.00	832.71	317.83
Density (g/cm³)	5.51	1.99	1.33
Surface Gravity (g)	1.00	4.78	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	832.715 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 171028

TIC

TIC 321030607

Gaia DR2

Gaia DR2 4477318138371083008

Gaia DR3

Gaia DR3 4477318138371083008

System

HD 171028

Percentile among Gas Giant cohort

Radius 13.200 R⊕ · percentile 49 / cohort 1771

Mass 832.715 M⊕ · percentile 63 / cohort 1747

Orbital period 550.00 d · percentile 69 / cohort 1533

Distance 111.66 pc · percentile 37 / cohort 1759

ESI 0.388 · percentile 82 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

550.000 days

Semi-major axis

1.3200 AU

Eccentricity

0.590

Inclination

— °

Year Length

A year here lasts about 1.51 Earth years on a highly eccentric trajectory at a mean orbital distance of 1.3200 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.388

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Santos et al. 2007

Instrument

HARPS Spectrograph

Publication

2007-11

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 221287 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 171028

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,671 K — cooler than the Sun (5,778 K)

Estimated Age

8.59 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

2.470 R☉

Stellar Mass

1.530 M☉

Metallicity [Fe/H]

-0.48

Extended Stellar Properties

Surface gravity (log g)

3.840 dex

Stellar density

0.087 g/cm³

Systemic radial velocity

13.64 km/s

Rotational v·sin i

2.14 km/s

Metallicity ratio

[Fe/H]

Distance

111.66 parsec

Light-years 364.18 ly

V-band magnitude

8.29 mag

Voyager-speed travel 6,422,359 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

8.927 mas

Total Proper Motion

45.321 mas/yr

PM Right Ascension

-42.87 mas/yr

PM Declination

-14.71 mas/yr

Galactic Cartesian (pc)

x = 0.139 · y = -0.983 · z = 0.121

Equatorial (J2000)

RA 278.06437° · Dec 6.94568°

Galactic ℓ, b

36.967° · 7.411°

Ecliptic λ, β

279.261° · 30.126°

HTM-20 index

-321890627