Key parameters at a glance

A radius of 7.87 Earth radii
A mass of 47.67 Earth masses
Surface gravity around 0.77 g
An orbital period of 110.900 days
Semi-major axis 0.5137 AU
Distance from Earth 204.72 light-years
Earth Similarity Index 0.358
Travel time at Voyager 1 speed 3,610,231 years

1 sibling around HD 177830

HD 177830 c 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 177830 c this	Neptune-like	7.87	47.67	110.900	—	2010
HD 177830 b	Gas Giant	13.50	537.13	410.100	—	1999

HD 177830 c Planet Profile

Physical Specs

Radius

7.87 R⊕

Radius (Jupiter)

0.702 R♃

Mass

47.67 M⊕

Mass (Jupiter)

0.150 M♃

Density

0.54 g/cm³

Surface Gravity

0.77 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.358

HZ Position Unknown

Controversial No

Discovery

Year 2010

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#161of 574

top 27.9%

This planet

7.87R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

TOI-3984 A b 7.90 R⊕ HIP 67522 c 7.94 R⊕ HIP 38594 c 7.94 R⊕

Metric	Earth	HD 177830 c	Jupiter
Radius (R⊕)	1.00	7.87	11.21
Mass (M⊕)	1.00	47.67	317.83
Density (g/cm³)	5.51	0.54	1.33
Surface Gravity (g)	1.00	0.77	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	47.673 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 177830

HIP

HIP 93746

TIC

TIC 265052133

Gaia DR2

Gaia DR2 2035963417721248128

Gaia DR3

Gaia DR3 2035963417721248128

System

HD 177830

Percentile among Neptune-like cohort

Radius 7.870 R⊕ · percentile 72 / cohort 574

Mass 47.673 M⊕ · percentile 69 / cohort 574

Orbital period 110.90 d · percentile 83 / cohort 524

Distance 62.77 pc · percentile 18 / cohort 572

ESI 0.358 · percentile 65 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

110.900 days

Semi-major axis

0.5137 AU

Eccentricity

0.300

Inclination

— °

Year Length

A year here lasts approximately 110.90 Earth days (30.4% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.5137 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

5.100 m/s

Transit mid-time (BJD)

2,455,177.0000

Long. of periastron (ω)

110.00°

Angular separation (arcsec)

8.18000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.358

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Meschiari et al. 2011

Instrument

HIRES Spectrometer

Publication

2011-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2010 at W. M. Keck Observatory (12 shown).

HD 156668 b · Super-Earth HD 1461 b · Sub-Neptune GJ 876 e · Sub-Neptune HAT-P-17 c · Gas Giant HD 97658 b · Sub-Neptune HD 163607 c · Gas Giant HD 218566 b · Neptune-like HD 102956 b · Gas Giant HD 163607 b · Gas Giant GJ 1148 b · Gas Giant HD 31253 b · Gas Giant HD 164509 b · Gas Giant

Host System: HD 177830

Spectral Class

K-type orange

Effective Temperature

4,949 K — cooler than the Sun (5,778 K)

Estimated Age

4.40 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.620 R☉

Stellar Mass

1.470 M☉

Metallicity [Fe/H]

0.55

Extended Stellar Properties

Surface gravity (log g)

3.650 dex

Systemic radial velocity

-72.14 km/s

Rotational v·sin i

0.68 km/s

Metallicity ratio

[Fe/H]

Distance

62.77 parsec

Light-years 204.72 ly

V-band magnitude

7.18 mag

Voyager-speed travel 3,610,231 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

15.903 mas

Total Proper Motion

66.767 mas/yr

PM Right Ascension

-41.33 mas/yr

PM Declination

-52.43 mas/yr

Galactic Cartesian (pc)

x = 0.253 · y = -0.863 · z = 0.437

Equatorial (J2000)

RA 286.33636° · Dec 25.92043°

Galactic ℓ, b

57.684° · 8.672°

Ecliptic λ, β

292.258° · 48.105°

HTM-20 index

-899348034

Observation Record

Photometric series

RV measurements

Stellar spectra

Archive notes

Similar Worlds

TOI-216.02

Neptune-like · K-type orange

Radius 8.00 R⊕ · 580.4 ly

Kepler-489 b

Neptune-like · K-type orange

Radius 7.72 R⊕ · 1,205.6 ly

KMT-2021-BLG-1689L b

Neptune-like · K-type orange

Radius 7.71 R⊕ · 23,483.2 ly

HATS-72 b

Neptune-like · K-type orange

Radius 8.10 R⊕ · 416.1 ly

K2-281 b

Neptune-like · K-type orange

Radius 8.18 R⊕ · 1,494.2 ly

TOI-1823 b

Neptune-like · K-type orange

Radius 7.54 R⊕ · 233.7 ly

Explore Related Categories

Neptune-like Planets Radial Velocity Discoveries W. M. Keck Observatory Mission K-type orange Hosts