Confirmed Exoplanet Discovered 2009

61 Vir c

A neptune-like orbiting the g-type yellow (sun-like) 61 Vir, located approximately 27.7 light-years from Earth.

Key parameters at a glance

  • A radius of 4.46 Earth radii
  • A mass of 18.20 Earth masses
  • Surface gravity around 0.91 g
  • An orbital period of 38.021 days
  • Semi-major axis 0.2175 AU
  • Distance from Earth 27.73 light-years
  • Earth Similarity Index 0.511
  • Travel time at Voyager 1 speed 489,091 years

Context from the literature

61 Virginis c is an exoplanet orbiting the 5th apparent-magnitude G-type main-sequence star 61 Virginis in the constellation Virgo. 61 Virginis c has a minimum mass of 18.2 times that of Earth and orbits one-fifth the distance to the star as Earth orbits the Sun, at a precise distance of 0.2175 AU with an eccentricity of 0.14. This planet would most likely be a gas giant like Uranus and Neptune. This planet was discovered on 14 December 2009 from using a precise radial velocity method taken at Keck and Anglo-Australian Observatories.

Excerpted from Wikipedia · full article

2 siblings around 61 Vir

61 Vir c shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
61 Vir b Sub-Neptune 2.11 5.10 4.215 2009
61 Vir c this Neptune-like 4.46 18.20 38.021 2009
61 Vir d Neptune-like 5.11 22.90 123.010 2009

61 Vir c Planet Profile

Physical Specs

Radius
4.46 R⊕
Radius (Jupiter)
0.398 R♃
Mass
18.20 M⊕
Mass (Jupiter)
0.057 M♃
Density
1.13 g/cm³
Surface Gravity
0.91 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.511
HZ Position Unknown
Controversial No

Discovery

Year 2009
Method Radial Velocity
Facility Multiple Observatories
Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#464of 574

top 80.7%

This planet

4.46R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth 61 Vir c Jupiter
Radius (R⊕)1.004.4611.21
Mass (M⊕)1.0018.20317.83
Density (g/cm³)5.511.131.33
Surface Gravity (g)1.000.912.53
Insolation (S⊕)1.000.037

Alternative Mass Estimates

Method Value Interpretation
Minimum mass (M sin i) 18.200 M⊕ Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD

HD 115617

HIP

HIP 64924

TIC

TIC 422478973

Gaia DR2

Gaia DR2 3507879565090229888

Gaia DR3

Gaia DR3 3507879565090229888

System

61 Vir

Percentile among Neptune-like cohort

Radius 4.460 R⊕ · percentile 19 / cohort 574
Mass 18.200 M⊕ · percentile 23 / cohort 574
Orbital period 38.02 d · percentile 65 / cohort 524
Distance 8.50 pc · percentile 1 / cohort 572
ESI 0.511 · percentile 92 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
38.021 days
Semi-major axis
0.2175 AU
Eccentricity
0.140
Inclination
°

Year Length

A year here lasts approximately 38.02 Earth days (10.4% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.2175 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

3.620 m/s

Transit mid-time (BJD)

2,455,036.2400

Long. of periastron (ω)

341.00°

Angular separation (arcsec)

25.60000

Eq. Temperature

 

Insolation (S⊕)

Earth = 1.00

Earth Similarity (ESI)

0.511

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Vogt et al. 2010

Instrument

Multiple Instruments

Publication

2010-01

Observation locale

Ground

Discovery cohort

Planets confirmed in 2009 at Multiple Observatories (3 shown).

Host System: 61 Vir

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,577 K — cooler than the Sun (5,778 K)

Estimated Age

8.96 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.963 R☉

Stellar Mass

0.942 M☉

Metallicity [Fe/H]

-0.01

Extended Stellar Properties

Surface gravity (log g)

4.340 dex

Stellar density

1.449 g/cm³

Systemic radial velocity

-8.20 km/s

Rotational v·sin i

1.90 km/s

Activity index (log R'HK)

-5.040

Metallicity ratio

[Fe/H]

Distance
8.50 parsec
Light-years 27.73 ly
V-band magnitude
4.70 mag
Voyager-speed travel 489,091 yr

Multi-band Host Photometry — 12 bands

0.14.70.07B4.70V4.54Gaia4.09TESS3.97Ic3.33J2.97H2.96K2.14W12.79W23.09W32.99W4

Astrometric Data

Parallax

117.573 mas

Total Proper Motion

1,508.842 mas/yr

PM Right Ascension

-1,070.81 mas/yr

PM Declination

-1,063.00 mas/yr

Galactic Cartesian (pc)

x = -0.894 · y = -0.318 · z = -0.314

Equatorial (J2000)

RA 199.59646° · Dec -18.31577°

Galactic ℓ, b

311.852° · 44.089°

Ecliptic λ, β

205.001° · -9.304°

HTM-20 index

224855835

Observation Record

Photometric series

1

RV measurements

6

Stellar spectra

9

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