Key parameters at a glance

A radius of 5.38 Earth radii
A mass of 25.00 Earth masses
Surface gravity around 0.86 g
An orbital period of 37.910 days
Semi-major axis 0.2290 AU
Distance from Earth 109.38 light-years
Earth Similarity Index 0.456
Travel time at Voyager 1 speed 1,928,962 years

Context from the literature

HD 11964 c is an extrasolar planet approximately 110 light-years away in the constellation of Cetus. The planet was discovered in a close-orbit around the yellow subgiant star HD 11964. The planet has a minimum mass 35 times the mass of Earth and is located in a mildly eccentric orbit which takes almost 38 days to complete. HD 11964 c was a possible planet discovered on the same day as HD 11964 b in 2005. HD 11964 c was first proposed in a paper published in 2007, and finally confirmed with new data presented in a review of multi-planet systems which appeared on the arXiv preprint website in 2008.

Excerpted from Wikipedia · full article

1 sibling around HD 11964

HD 11964 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 11964 c this	Neptune-like	5.38	25.00	37.910	—	2008
HD 11964 b	Gas Giant	14.10	198.00	1,945.000	—	2005

HD 11964 c Planet Profile

Physical Specs

Radius

5.38 R⊕

Radius (Jupiter)

0.480 R♃

Mass

25.00 M⊕

Mass (Jupiter)

0.079 M♃

Density

0.88 g/cm³

Surface Gravity

0.86 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.456

HZ Position Unknown

Controversial No

Discovery

Year 2008

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#331of 574

top 57.5%

This planet

5.38R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Kepler-677 b 5.38 R⊕ HD 10180 e 5.39 R⊕ Kepler-1737 b 5.40 R⊕

Metric	Earth	HD 11964 c	Jupiter
Radius (R⊕)	1.00	5.38	11.21
Mass (M⊕)	1.00	25.00	317.83
Density (g/cm³)	5.51	0.88	1.33
Surface Gravity (g)	1.00	0.86	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	25.000 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 11964

HIP

HIP 9094

TIC

TIC 24978373

Gaia DR2

Gaia DR2 2462426800883134336

Gaia DR3

Gaia DR3 2462426800883134336

System

HD 11964

Percentile among Neptune-like cohort

Radius 5.380 R⊕ · percentile 42 / cohort 574

Mass 25.000 M⊕ · percentile 42 / cohort 574

Orbital period 37.91 d · percentile 65 / cohort 524

Distance 33.54 pc · percentile 10 / cohort 572

ESI 0.456 · percentile 82 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

37.910 days

Semi-major axis

0.2290 AU

Eccentricity

0.300

Inclination

— °

Year Length

A year here lasts approximately 37.91 Earth days (10.4% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.2290 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

4.650 m/s

Transit mid-time (BJD)

2,455,199.9400

Long. of periastron (ω)

102.00°

Angular separation (arcsec)

6.83000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.456

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Wright et al. 2009

Instrument

HIRES Spectrometer

Publication

2009-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2008 at W. M. Keck Observatory (7 shown).

HD 183263 c · Gas Giant HD 187123 c · Gas Giant HD 73534 b · Gas Giant HD 11506 c · Gas Giant HR 8799 d · Gas Giant HD 179079 b · Unclassified HD 7924 b · Unclassified

Host System: HD 11964

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,303 K — cooler than the Sun (5,778 K)

Estimated Age

7.45 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

2.010 R☉

Stellar Mass

0.910 M☉

Metallicity [Fe/H]

0.10

Extended Stellar Properties

Surface gravity (log g)

3.791 dex

Stellar density

0.158 g/cm³

Systemic radial velocity

-9.32 km/s

Rotational v·sin i

2.74 km/s

Activity index (log R'HK)

-5.160

Metallicity ratio

[M/H]

Distance

33.54 parsec

Light-years 109.38 ly

V-band magnitude

6.42 mag

Voyager-speed travel 1,928,962 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

29.789 mas

Total Proper Motion

439.807 mas/yr

PM Right Ascension

-366.96 mas/yr

PM Declination

-242.43 mas/yr

Galactic Cartesian (pc)

x = 0.858 · y = 0.481 · z = -0.178

Equatorial (J2000)

RA 29.28843° · Dec -10.24347°

Galactic ℓ, b

168.576° · -67.092°

Ecliptic λ, β

23.370° · -20.772°

HTM-20 index

1598494557

Observation Record

Photometric series

RV measurements

Stellar spectra

Archive notes

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