Key parameters at a glance

A radius of 0.91 Earth radii
A mass of 0.70 Earth masses
Surface gravity around 0.84 g
An orbital period of 9.977 days
Semi-major axis 0.0677 AU
Equilibrium temperature 417 K (144 °C)
Distance from Earth 101.52 light-years
Earth Similarity Index 0.732
Travel time at Voyager 1 speed 1,790,322 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

TOI-700 is a red dwarf 101.4 light-years away from Earth located in the Dorado constellation that hosts TOI-700 d, the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS).

Excerpted from Wikipedia · full article

3 siblings around TOI-700

TOI-700 b 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
TOI-700 b this	Rocky Terrestrial	0.91	0.70	9.977	417	2020
TOI-700 c	Sub-Neptune	2.60	7.27	16.051	356	2020
TOI-700 e	Rocky Terrestrial	0.95	0.82	27.810	273	2023
TOI-700 d	Rocky Terrestrial	1.07	1.25	37.424	269	2020

TOI-700 b Planet Profile

Physical Specs

Radius

0.91 R⊕

Radius (Jupiter)

0.082 R♃

Mass

0.70 M⊕

Mass (Jupiter)

0.002 M♃

Density

5.07 g/cm³

Surface Gravity

0.84 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.732

HZ Position Inner

Controversial No

Discovery

Year 2020

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#403of 570

top 70.5%

This planet

0.91R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1934 b 0.91 R⊕ YZ Cet b 0.91 R⊕ Kepler-1525 b 0.91 R⊕

Metric	Earth	TOI-700 b	Jupiter
Radius (R⊕)	1.00	0.91	11.21
Mass (M⊕)	1.00	0.70	317.83
Density (g/cm³)	5.51	5.07	1.33
Surface Gravity (g)	1.00	0.84	2.53
Insolation (S⊕)	1.00	4.98	0.037

Star Catalogue Identifiers

TIC

TIC 150428135

Gaia DR2

Gaia DR2 5284517766615492736

Gaia DR3

Gaia DR3 5284517766615850752

System

TOI-700

Percentile among Rocky Terrestrial cohort

Radius 0.914 R⊕ · percentile 29 / cohort 570

Mass 0.704 M⊕ · percentile 25 / cohort 570

Orbital period 9.98 d · percentile 78 / cohort 567

Distance 31.13 pc · percentile 14 / cohort 566

ESI 0.732 · percentile 84 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

9.977 days

Semi-major axis

0.0677 AU

Eccentricity

0.075

Inclination

89.60 °

Year Length

A year here lasts approximately 9.98 Earth days (2.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0677 AU.

Transit Fingerprint

Depth

0.046 %

Duration

2.170 h

Impact parameter b

0.240

Rp / R★

0.019930

Transit midpoint (BJD)

2,458,880.0993

Photometric dip

Transit produces a flux drop of 460 ppm lasting ≈ 2.17 h.

Extended Orbital Architecture

Planet / star radius ratio

0.019930

Semi-major axis / stellar radius

34.300

Impact parameter (b)

0.240

Transit mid-time (BJD)

2,458,880.0993

Long. of periastron (ω)

-150.00°

Angular separation (arcsec)

2.17000

Eq. Temperature

417K

(144 °C)

Insolation (S⊕)

4.98

Earth = 1.00

Earth Similarity (ESI)

0.732

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.

Discovery Paper

Primary reference

Gilbert et al. 2020

Instrument

TESS CCD Array

Publication

2020-09

Observation locale

Space

Discovery cohort

Planets confirmed in 2020 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-700 d · Rocky Terrestrial TOI-237 b · Super-Earth TOI-1266 c · Super-Earth LTT 3780 c · Sub-Neptune TOI-700 c · Sub-Neptune TOI-776 c · Sub-Neptune TOI-942 c · Neptune-like TOI-776 b · Super-Earth TOI-1266 b · Sub-Neptune TOI-540 b · Rocky Terrestrial LHS 1815 b · Rocky Terrestrial TOI-122 b · Sub-Neptune

Host System: TOI-700

Spectral Class

M-type red dwarf

Effective Temperature

3,459 K — cooler than the Sun (5,778 K)

Estimated Age

1.50 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.421 R☉

Stellar Mass

0.415 M☉

Metallicity [Fe/H]

-0.07

Extended Stellar Properties

Surface gravity (log g)

4.809 dex

Stellar density

7.860 g/cm³

Systemic radial velocity

-4.40 km/s

Rotation period

54.00 days

Metallicity ratio

[Fe/H]

Distance

31.13 parsec

Light-years 101.52 ly

V-band magnitude

13.15 mag

Voyager-speed travel 1,790,322 yr

Multi-band Host Photometry — 15 bands

Astrometric Data

Parallax

32.098 mas

Total Proper Motion

191.673 mas/yr

PM Right Ascension

-102.75 mas/yr

PM Declination

161.81 mas/yr

Galactic Cartesian (pc)

x = -0.051 · y = 0.410 · z = -0.911

Equatorial (J2000)

RA 97.09572° · Dec -65.57861°

Galactic ℓ, b

275.468° · -26.881°

Ecliptic λ, β

164.422° · -86.961°

HTM-20 index

-455754236

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