Key parameters at a glance

A radius of 2.53 Earth radii
A mass of 6.79 Earth masses
Surface gravity around 1.06 g
An orbital period of 17.181 days
Semi-major axis 0.1235 AU
Equilibrium temperature 656 K (383 °C)
Distance from Earth 146.17 light-years
Earth Similarity Index 0.383
Travel time at Voyager 1 speed 2,577,680 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around HD 15337

HD 15337 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 15337 b	Super-Earth	1.77	6.52	4.756	1,001	2019
HD 15337 c this	Sub-Neptune	2.53	6.79	17.181	656	2019

HD 15337 c Planet Profile

Physical Specs

Radius

2.53 R⊕

Radius (Jupiter)

0.225 R♃

Mass

6.79 M⊕

Mass (Jupiter)

0.021 M♃

Density

2.30 g/cm³

Surface Gravity

1.06 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.383

HZ Position Inner

Controversial No

Discovery

Year 2019

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#1145of 1978

top 57.8%

This planet

2.53R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

HIP 8152 c 2.52 R⊕ TOI-1136 g 2.53 R⊕ Kepler-313 b 2.53 R⊕

Metric	Earth	HD 15337 c	Jupiter
Radius (R⊕)	1.00	2.53	11.21
Mass (M⊕)	1.00	6.79	317.83
Density (g/cm³)	5.51	2.30	1.33
Surface Gravity (g)	1.00	1.06	2.53
Insolation (S⊕)	1.00	45.07	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	6.792 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 15337

HIP

HIP 11433

TIC

TIC 120896927

Gaia DR2

Gaia DR2 5068777809824976256

Gaia DR3

Gaia DR3 5068777809824976256

System

HD 15337

Percentile among Sub-Neptune cohort

Radius 2.526 R⊕ · percentile 42 / cohort 1978

Mass 6.792 M⊕ · percentile 37 / cohort 1978

Orbital period 17.18 d · percentile 56 / cohort 1946

Distance 44.82 pc · percentile 11 / cohort 1975

ESI 0.383 · percentile 49 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

17.181 days

Semi-major axis

0.1235 AU

Eccentricity

0.096

Inclination

88.41 °

Year Length

A year here lasts approximately 17.18 Earth days (4.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1235 AU.

Transit Fingerprint

Depth

0.076 %

Duration

2.232 h

Impact parameter b

0.876

Rp / R★

0.027070

Transit midpoint (BJD)

2,458,414.5516

Photometric dip

Transit produces a flux drop of 758 ppm lasting ≈ 2.23 h.

Extended Orbital Architecture

Planet / star radius ratio

0.027070

Semi-major axis / stellar radius

31.870

Impact parameter (b)

0.876

RV semi-amplitude (K)

1.920 m/s

Transit mid-time (BJD)

2,458,414.5516

Long. of periastron (ω)

56.63°

Angular separation (arcsec)

2.76000

Eq. Temperature

656K

(383 °C)

Insolation (S⊕)

45.07

Earth = 1.00

Earth Similarity (ESI)

0.383

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.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Gandolfi et al. 2019

Instrument

TESS CCD Array

Publication

2019-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2019 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

LP 791-18 c · Sub-Neptune LTT 1445 A b · Super-Earth TOI-270 d · Sub-Neptune L 98-59 d · Super-Earth GJ 357 b · Rocky Terrestrial GJ 143 b · Sub-Neptune HD 23472 c · Super-Earth L 98-59 c · Super-Earth LP 791-18 b · Rocky Terrestrial TOI-270 c · Sub-Neptune HD 23472 b · Sub-Neptune TOI-270 b · Super-Earth

Host System: HD 15337

Spectral Class

K-type orange

Effective Temperature

5,131 K — cooler than the Sun (5,778 K)

Estimated Age

9.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.855 R☉

Stellar Mass

0.829 M☉

Metallicity [Fe/H]

0.03

Extended Stellar Properties

Surface gravity (log g)

4.480 dex

Stellar density

1.881 g/cm³

Systemic radial velocity

-3.80 km/s

Rotational v·sin i

1.00 km/s

Rotation period

36.53 days

Metallicity ratio

[Fe/H]

Distance

44.82 parsec

Light-years 146.17 ly

V-band magnitude

9.10 mag

Voyager-speed travel 2,577,680 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

22.285 mas

Total Proper Motion

224.045 mas/yr

PM Right Ascension

-73.59 mas/yr

PM Declination

-211.61 mas/yr

Galactic Cartesian (pc)

x = 0.709 · y = 0.532 · z = -0.464

Equatorial (J2000)

RA 36.86788° · Dec -27.63612°

Galactic ℓ, b

219.862° · -68.709°

Ecliptic λ, β

23.154° · -39.569°

HTM-20 index

1724703111

Similar Worlds

K2-119 b

Sub-Neptune · K-type orange

Radius 2.53 R⊕ · 1,192.4 ly

Kepler-1350 b

Sub-Neptune · K-type orange

Radius 2.52 R⊕ · 1,111.2 ly

K2-179 b

Sub-Neptune · K-type orange

Radius 2.51 R⊕ · 622.3 ly

TOI-1648 b

Sub-Neptune · K-type orange

Radius 2.54 R⊕ · 227.8 ly

K2-118 b

Sub-Neptune · K-type orange

Radius 2.54 R⊕ · 1,049.3 ly

K2-16 c

Sub-Neptune · K-type orange

Radius 2.54 R⊕ · 1,092.5 ly

Explore Related Categories

Sub-Neptune Planets Transit Discoveries Transiting Exoplanet Survey Satellite (TESS) Mission K-type orange Hosts