Key parameters at a glance

A radius of 1.34 Earth radii
A mass of 2.73 Earth masses
Surface gravity around 1.52 g
An orbital period of 5.359 days
Semi-major axis 0.0381 AU
Equilibrium temperature 431 K (158 °C)
Distance from Earth 22.40 light-years
Earth Similarity Index 0.683
Travel time at Voyager 1 speed 395,105 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

LTT 1445 is a triple M-dwarf system 22.4 light-years distant in the constellation Eridanus. The primary LTT 1445 A hosts two exoplanets—one discovered in 2019 that transits the star every 5.36 days, and another found in 2021 that transits the star every 3.12 days, close to a 12:7 resonance. As of October 2022 it is the second closest transiting exoplanet system discovered, with the closest being HD 219134 bc.

Excerpted from Wikipedia · full article

1 sibling around LTT 1445 A

LTT 1445 A 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
LTT 1445 A c	Rocky Terrestrial	1.15	1.54	3.124	508	2022
LTT 1445 A b this	Super-Earth	1.34	2.73	5.359	431	2019

LTT 1445 A b Planet Profile

Physical Specs

Radius

1.34 R⊕

Radius (Jupiter)

0.120 R♃

Mass

2.73 M⊕

Mass (Jupiter)

0.009 M♃

Density

6.20 g/cm³

Surface Gravity

1.52 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.683

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

#1010of 1176

top 85.8%

This planet

1.34R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-442 b 1.34 R⊕ Kepler-191 b 1.34 R⊕ Kepler-285 b 1.34 R⊕

Metric	Earth	LTT 1445 A b	Jupiter
Radius (R⊕)	1.00	1.34	11.21
Mass (M⊕)	1.00	2.73	317.83
Density (g/cm³)	5.51	6.20	1.33
Surface Gravity (g)	1.00	1.52	2.53
Insolation (S⊕)	1.00	5.70	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	2.730 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HIP

HIP 14101

TIC

TIC 98796344

Gaia DR2

Gaia DR2 5153091836072107136

Gaia DR3

Gaia DR3 5153091836072107136

System

LTT 1445

Percentile among Super-Earth cohort

Radius 1.340 R⊕ · percentile 13 / cohort 1176

Mass 2.730 M⊕ · percentile 27 / cohort 1176

Orbital period 5.36 d · percentile 42 / cohort 1164

Distance 6.87 pc · percentile 1 / cohort 1171

ESI 0.683 · percentile 84 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

5.359 days

Semi-major axis

0.0381 AU

Eccentricity

0.180

Inclination

89.53 °

Year Length

A year here lasts approximately 5.36 Earth days (1.5% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0381 AU.

Transit Fingerprint

Depth

0.230 %

Duration

1.366 h

Impact parameter b

0.250

Rp / R★

0.045400

Transit midpoint (BJD)

2,458,412.7091

Photometric dip

Transit produces a flux drop of 2,300 ppm lasting ≈ 1.37 h.

Extended Orbital Architecture

Planet / star radius ratio

0.045400

Semi-major axis / stellar radius

30.900

Impact parameter (b)

0.250

RV semi-amplitude (K)

2.470 m/s

Transit mid-time (BJD)

2,458,412.7091

Long. of periastron (ω)

244.00°

Angular separation (arcsec)

5.55000

Eq. Temperature

431K

(158 °C)

Insolation (S⊕)

5.70

Earth = 1.00

Earth Similarity (ESI)

0.683

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

Winters et al. 2019

Instrument

TESS CCD Array

Publication

2019-10

Observation locale

Space

Discovery cohort

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

LP 791-18 c · Sub-Neptune 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 L 98-59 b · Rocky Terrestrial

Host System: LTT 1445 A

Spectral Class

M-type red dwarf

Effective Temperature

3,562 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.271 R☉

Stellar Mass

0.257 M☉

Metallicity [Fe/H]

-0.34

Extended Stellar Properties

Surface gravity (log g)

4.974 dex

Stellar density

17.300 g/cm³

Systemic radial velocity

-5.43 km/s

Rotational v·sin i

3.40 km/s

Metallicity ratio

[Fe/H]

Distance

6.87 parsec

Light-years 22.40 ly

V-band magnitude

10.59 mag

Voyager-speed travel 395,105 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

145.547 mas

Total Proper Motion

456.512 mas/yr

PM Right Ascension

-369.20 mas/yr

PM Declination

-268.51 mas/yr

Galactic Cartesian (pc)

x = 0.672 · y = 0.683 · z = -0.286

Equatorial (J2000)

RA 45.46248° · Dec -16.59450°

Galactic ℓ, b

200.487° · -58.076°

Ecliptic λ, β

37.354° · -32.259°

HTM-20 index

-102612284

Observation Record

Photometric series

Transmission spectra

Emission spectra

Archive notes

Wikipedia → Image: Wikimedia Commons · Meli thev · CC BY-SA 4.0