Key parameters at a glance

A radius of 5.08 Earth radii
A mass of 4.70 Earth masses
Surface gravity around 0.18 g
An orbital period of 8.249 days
Semi-major axis 0.0824 AU
Equilibrium temperature 953 K (680 °C)
Distance from Earth 352.90 light-years
Earth Similarity Index 0.143
Travel time at Voyager 1 speed 6,223,348 years
Almost certainly tidally locked to its host star given the close orbit

3 siblings around V1298 Tau

V1298 Tau c shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
V1298 Tau c this	Neptune-like	5.08	4.70	8.249	953	2019
V1298 Tau d	Neptune-like	6.53	6.00	12.401	831	2019
V1298 Tau b	Neptune-like	9.41	13.10	24.140	666	2019
V1298 Tau e	Gas Giant	10.17	15.30	48.678	527	2019

V1298 Tau c Planet Profile

Physical Specs

Radius

5.08 R⊕

Radius (Jupiter)

0.453 R♃

Mass

4.70 M⊕

Mass (Jupiter)

0.015 M♃

Density

0.20 g/cm³

Surface Gravity

0.18 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.143

HZ Position Inner

Controversial No

Discovery

Year 2019

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#373of 574

top 64.8%

This planet

5.08R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

TOI-6223 b 5.07 R⊕ TOI-421 c 5.09 R⊕ TOI-6651 b 5.09 R⊕

Metric	Earth	V1298 Tau c	Jupiter
Radius (R⊕)	1.00	5.08	11.21
Mass (M⊕)	1.00	4.70	317.83
Density (g/cm³)	5.51	0.20	1.33
Surface Gravity (g)	1.00	0.18	2.53
Insolation (S⊕)	1.00	146.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	4.700 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 15756231

Gaia DR2

Gaia DR2 51886335968692480

Gaia DR3

Gaia DR3 51886335968692480

System

V1298 Tau

Percentile among Neptune-like cohort

Radius 5.080 R⊕ · percentile 35 / cohort 574

Mass 4.700 M⊕ · percentile 1 / cohort 574

Orbital period 8.25 d · percentile 32 / cohort 524

Distance 108.20 pc · percentile 25 / cohort 572

ESI 0.143 · percentile 11 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

8.249 days

Semi-major axis

0.0824 AU

Eccentricity

0.009

Inclination

88.49 °

Year Length

A year here lasts approximately 8.25 Earth days (2.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0824 AU.

Transit Fingerprint

Duration

4.890 h

Impact parameter b

0.360

Rp / R★

0.035600

Transit midpoint (BJD)

2,458,293.3412

Extended Orbital Architecture

Planet / star radius ratio

0.035600

Semi-major axis / stellar radius

13.189

Impact parameter (b)

0.360

RV semi-amplitude (K)

22.000 m/s

Transit mid-time (BJD)

2,458,293.3412

Long. of periastron (ω)

87.84°

Sky-projected obliquity (λ)

4.90°

Angular separation (arcsec)

0.76200

Eq. Temperature

953K

(680 °C)

Insolation (S⊕)

146.00

Earth = 1.00

Earth Similarity (ESI)

0.143

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

David et al. 2019

Instrument

Kepler CCD Array

Publication

2019-11

Observation locale

Space

Discovery cohort

Planets confirmed in 2019 at K2 (12 shown).

EPIC 206032309 b · Rocky Terrestrial EPIC 201833600 c · Rocky Terrestrial EPIC 206215704 b · Rocky Terrestrial EPIC 201754305 d · Rocky Terrestrial EPIC 201841433 b · Rocky Terrestrial EPIC 206317286 b · Rocky Terrestrial EPIC 201615463 c · Rocky Terrestrial EPIC 212499991 b · Super-Earth EPIC 220554210 c · Super-Earth EPIC 201497682 b · Rocky Terrestrial K2-133 e · Super-Earth EPIC 206024342 b · Super-Earth

Host System: V1298 Tau

Spectral Class

K-type orange

Effective Temperature

4,970 K — cooler than the Sun (5,778 K)

Estimated Age

0.02 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.320 R☉

Stellar Mass

1.100 M☉

Metallicity [Fe/H]

0.10

Extended Stellar Properties

Surface gravity (log g)

4.227 dex

Stellar density

0.679 g/cm³

Systemic radial velocity

16.15 km/s

Rotational v·sin i

24.77 km/s

Rotation period

2.91 days

Metallicity ratio

[Fe/H]

Distance

108.20 parsec

Light-years 352.90 ly

V-band magnitude

10.12 mag

Voyager-speed travel 6,223,348 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

9.214 mas

Total Proper Motion

16.905 mas/yr

PM Right Ascension

5.23 mas/yr

PM Declination

-16.08 mas/yr

Galactic Cartesian (pc)

x = 0.450 · y = 0.824 · z = 0.345

Equatorial (J2000)

RA 61.33165° · Dec 20.15703°

Galactic ℓ, b

172.895° · -23.377°

Ecliptic λ, β

63.228° · -0.658°

HTM-20 index

-403262256

Similar Worlds

Kepler-1314 b

Neptune-like · K-type orange

Radius 5.11 R⊕ · 463.1 ly

TIC 88785435 b

Neptune-like · K-type orange

Radius 5.03 R⊕ · 399.2 ly

CoRoT-24 c

Neptune-like · K-type orange

Radius 5.00 R⊕ · 1,929.4 ly

NGTS-14 A b

Neptune-like · K-type orange

Radius 4.98 R⊕ · 1,050.7 ly

Kepler-257 d

Neptune-like · K-type orange

Radius 4.95 R⊕ · 2,544.9 ly

TOI-1272 c

Neptune-like · K-type orange

Radius 4.95 R⊕ · 448.7 ly

Explore Related Categories

Neptune-like Planets Transit Discoveries K2 Mission K-type orange Hosts