Key parameters at a glance
- A radius of 4.59 Earth radii
- A mass of 19.07 Earth masses
- Surface gravity around 0.91 g
- An orbital period of 3.835 days
- Semi-major axis 0.0490 AU
- Distance from Earth 238.47 light-years
- Earth Similarity Index 0.501
- Travel time at Voyager 1 speed 4,205,342 years
Context from the literature
HD 219828 b is an extrasolar planet approximately 265 light years away in the constellation of Pegasus. This is a Neptune-mass planet at least 21 times more massive than Earth. The planet's composition is unknown, but it may be similar to the ice giants Uranus and Neptune, or alternatively it may be a mainly rocky like Super-Earth.
Excerpted from Wikipedia · full article
1 sibling around HD 219828
HD 219828 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 219828 b this | Neptune-like | 4.59 | 19.07 | 3.835 | — | 2007 |
| HD 219828 c | Gas Giant | 12.20 | 5,102.42 | 4,789.873 | — | 2016 |
HD 219828 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#449of 574
top 78.0%
This planet
4.59R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | HD 219828 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 4.59 | 11.21 |
| Mass (M⊕) | 1.00 | 19.07 | 317.83 |
| Density (g/cm³) | 5.51 | 1.08 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.91 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 19.070 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 219828
HIP
HIP 115100
TIC
TIC 243085377
Gaia DR2
Gaia DR2 2824958015312906240
Gaia DR3
Gaia DR3 2824958015312906240
System
HD 219828
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.83 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0490 AU.
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.501
0 = alien, 1 = Earth-identical
Discovery Paper
Primary reference
Melo et al. 2007Instrument
HARPS Spectrograph
Publication
2007-05
Observation locale
Ground
Discovery cohort
Planets confirmed in 2007 at La Silla Observatory (10 shown).
Host System: HD 219828
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,891 K — hotter than the Sun (5,778 K)
Estimated Age
5.69 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.560 R☉
Stellar Mass
1.040 M☉
Metallicity [Fe/H]
0.19
Extended Stellar Properties
Surface gravity (log g)
4.170 dex
Stellar density
0.326 g/cm³
Systemic radial velocity
-24.03 km/s
Rotational v·sin i
2.90 km/s
Rotation period
31.70 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
13.649 mas
Total Proper Motion
7.887 mas/yr
PM Right Ascension
-5.08 mas/yr
PM Declination
6.04 mas/yr
Galactic Cartesian (pc)
x = 0.932 · y = -0.170 · z = 0.320
Equatorial (J2000)
RA 349.69470° · Dec 18.64575°
Galactic ℓ, b
94.266° · -39.013°
Ecliptic λ, β
358.255° · 21.147°
HTM-20 index
1058153528
Observation Record
Photometric series
1
RV measurements
1
Stellar spectra
1
Archive notes
1
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