Key parameters at a glance

A radius of 1.15 Earth radii
A mass of 1.54 Earth masses
Surface gravity around 1.17 g
An orbital period of 3.124 days
Semi-major axis 0.0266 AU
Equilibrium temperature 508 K (235 °C)
Distance from Earth 22.40 light-years
Earth Similarity Index 0.621
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 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
LTT 1445 A c this	Rocky Terrestrial	1.15	1.54	3.124	508	2022
LTT 1445 A b	Super-Earth	1.34	2.73	5.359	431	2019

LTT 1445 A c Planet Profile

Physical Specs

Radius

1.15 R⊕

Radius (Jupiter)

0.102 R♃

Mass

1.54 M⊕

Mass (Jupiter)

0.005 M♃

Density

5.57 g/cm³

Surface Gravity

1.17 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.621

HZ Position Inner

Controversial No

Discovery

Year 2022

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#166of 570

top 28.9%

This planet

1.15R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1763 b 1.15 R⊕ Kepler-339 c 1.15 R⊕ Kepler-1240 b 1.15 R⊕

Metric	Earth	LTT 1445 A c	Jupiter
Radius (R⊕)	1.00	1.15	11.21
Mass (M⊕)	1.00	1.54	317.83
Density (g/cm³)	5.51	5.57	1.33
Surface Gravity (g)	1.00	1.17	2.53
Insolation (S⊕)	1.00	10.90	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	1.540 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 Rocky Terrestrial cohort

Radius 1.147 R⊕ · percentile 71 / cohort 570

Mass 1.540 M⊕ · percentile 63 / cohort 570

Orbital period 3.12 d · percentile 35 / cohort 567

Distance 6.87 pc · percentile 4 / cohort 566

ESI 0.621 · percentile 80 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

3.124 days

Semi-major axis

0.0266 AU

Eccentricity

0.223

Inclination

87.43 °

Year Length

A year here lasts approximately 3.12 Earth days (0.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0266 AU.

Transit Fingerprint

Depth

0.157 %

Duration

0.482 h

Impact parameter b

0.937

Rp / R★

0.039600

Transit midpoint (BJD)

2,458,412.5816

Photometric dip

Transit produces a flux drop of 1,570 ppm lasting ≈ 0.48 h.

Extended Orbital Architecture

Planet / star radius ratio

0.039600

Semi-major axis / stellar radius

21.560

Impact parameter (b)

0.937

RV semi-amplitude (K)

1.670 m/s

Transit mid-time (BJD)

2,458,412.5816

Long. of periastron (ω)

163.00°

Angular separation (arcsec)

3.87000

Eq. Temperature

508K

(235 °C)

Insolation (S⊕)

10.90

Earth = 1.00

Earth Similarity (ESI)

0.621

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. 2021

Instrument

TESS CCD Array

Publication

2021-07

Observation locale

Space

Discovery cohort

Planets confirmed in 2022 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-1452 b · Super-Earth TOI-712 d · Sub-Neptune TOI-1468 c · Sub-Neptune TOI-2136 b · Sub-Neptune TOI-712 c · Sub-Neptune LP 890-9 b · Super-Earth TOI-2081 b · Sub-Neptune GJ 3929 b · Rocky Terrestrial HD 260655 c · Super-Earth HD 73583 c · Sub-Neptune TOI-1759 b · Sub-Neptune TOI-1246 e · Sub-Neptune

Host System: LTT 1445 A

Spectral Class

M-type red dwarf

Effective Temperature

3,340 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.265 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

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