Key parameters at a glance

A radius of 13.30 Earth radii
A mass of 778.68 Earth masses
Surface gravity around 4.40 g
An orbital period of 408.600 days
Semi-major axis 1.2900 AU
Distance from Earth 206.94 light-years
Earth Similarity Index 0.381
Travel time at Voyager 1 speed 3,649,389 years

1 sibling around HD 154857

HD 154857 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 154857 b this	Gas Giant	13.30	778.68	408.600	—	2004
HD 154857 c	Gas Giant	13.20	819.97	3,452.000	—	2014

HD 154857 b Planet Profile

Physical Specs

Radius

13.30 R⊕

Radius (Jupiter)

1.180 R♃

Mass

778.68 M⊕

Mass (Jupiter)

2.450 M♃

Density

1.82 g/cm³

Surface Gravity

4.40 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.381

HZ Position Unknown

Controversial No

Discovery

Year 2004

Method Radial Velocity

Facility Anglo-Australian Telescope

Telescope 3.9 m Anglo-Australian Telescope

Size rank in cohort

Rank by radius

#793of 1771

top 44.7%

This planet

13.30R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 12661 b 13.30 R⊕ HD 129445 b 13.30 R⊕ GJ 876 b 13.30 R⊕

Metric	Earth	HD 154857 b	Jupiter
Radius (R⊕)	1.00	13.30	11.21
Mass (M⊕)	1.00	778.68	317.83
Density (g/cm³)	5.51	1.82	1.33
Surface Gravity (g)	1.00	4.40	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	778.684 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 154857

HIP

HIP 84069

TIC

TIC 173552927

Gaia DR2

Gaia DR2 5917212800626605824

Gaia DR3

Gaia DR3 5917212800626605824

System

HD 154857

Percentile among Gas Giant cohort

Radius 13.300 R⊕ · percentile 53 / cohort 1771

Mass 778.684 M⊕ · percentile 61 / cohort 1747

Orbital period 408.60 d · percentile 64 / cohort 1533

Distance 63.45 pc · percentile 26 / cohort 1759

ESI 0.381 · percentile 80 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

408.600 days

Semi-major axis

1.2900 AU

Eccentricity

0.460

Inclination

— °

Year Length

A year here lasts about 1.12 Earth years on a highly eccentric trajectory at a mean orbital distance of 1.2900 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.381

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Mccarthy et al. 2004

Instrument

UCLES Spectrograph

Publication

2004-12

Observation locale

Ground

Discovery cohort

Planets confirmed in 2004 at Anglo-Australian Telescope (3 shown).

HD 117618 b · Neptune-like HD 208487 b · Gas Giant HD 160691 c · Unclassified

Host System: HD 154857

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,589 K — cooler than the Sun (5,778 K)

Estimated Age

5.64 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

2.300 R☉

Stellar Mass

1.960 M☉

Metallicity [Fe/H]

-0.22

Extended Stellar Properties

Surface gravity (log g)

4.010 dex

Stellar density

0.119 g/cm³

Systemic radial velocity

28.06 km/s

Rotational v·sin i

1.40 km/s

Activity index (log R'HK)

-5.140

Metallicity ratio

[Fe/H]

Distance

63.45 parsec

Light-years 206.94 ly

V-band magnitude

7.24 mag

Voyager-speed travel 3,649,389 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

15.732 mas

Total Proper Motion

103.898 mas/yr

PM Right Ascension

87.58 mas/yr

PM Declination

-55.89 mas/yr

Galactic Cartesian (pc)

x = -0.116 · y = -0.537 · z = -0.836

Equatorial (J2000)

RA 257.81619° · Dec -56.68104°

Galactic ℓ, b

333.288° · -10.026°

Ecliptic λ, β

261.997° · -33.580°

HTM-20 index

748696309