Key parameters at a glance

A radius of 1.40 Earth radii
A mass of 2.02 Earth masses
Surface gravity around 1.04 g
An orbital period of 0.447 days
Semi-major axis 0.0106 AU
Equilibrium temperature 2,319 K (2046 °C)
Distance from Earth 279.84 light-years
Earth Similarity Index 0.112
Travel time at Voyager 1 speed 4,934,953 years

1 sibling around TOI-561

TOI-561 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
TOI-561 b this	Super-Earth	1.40	2.02	0.447	2,319	2020
TOI-561 c	Sub-Neptune	2.87	5.93	10.779	802	2020

TOI-561 b Planet Profile

Physical Specs

Radius

1.40 R⊕

Radius (Jupiter)

0.125 R♃

Mass

2.02 M⊕

Mass (Jupiter)

0.006 M♃

Density

4.10 g/cm³

Surface Gravity

1.04 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.112

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

#935of 1176

top 79.4%

This planet

1.40R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-186 d 1.40 R⊕ K2-85 b 1.40 R⊕ TOI-5489 b 1.40 R⊕

Metric	Earth	TOI-561 b	Jupiter
Radius (R⊕)	1.00	1.40	11.21
Mass (M⊕)	1.00	2.02	317.83
Density (g/cm³)	5.51	4.10	1.33
Surface Gravity (g)	1.00	1.04	2.53
Insolation (S⊕)	1.00	4,709.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	2.020 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 377064495

Gaia DR2

Gaia DR2 3850421005290172416

Gaia DR3

Gaia DR3 3850421005290172416

System

TOI-561

Percentile among Super-Earth cohort

Radius 1.397 R⊕ · percentile 20 / cohort 1176

Mass 2.020 M⊕ · percentile 1 / cohort 1176

Orbital period 0.45 d · percentile 1 / cohort 1164

Distance 85.80 pc · percentile 16 / cohort 1171

ESI 0.112 · percentile 1 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

0.447 days

Semi-major axis

0.0106 AU

Eccentricity

0.000

Inclination

87.00 °

Year Length

A year here lasts roughly 10.7 hours long on a nearly circular orbit at a mean orbital distance of 0.0106 AU.

Transit Fingerprint

Depth

0.029 %

Duration

1.308 h

Impact parameter b

0.140

Rp / R★

0.015190

Transit midpoint (BJD)

2,459,317.7500

Photometric dip

Transit produces a flux drop of 294 ppm lasting ≈ 1.31 h.

Extended Orbital Architecture

Planet / star radius ratio

0.015190

Semi-major axis / stellar radius

2.683

Impact parameter (b)

0.140

RV semi-amplitude (K)

1.950 m/s

Transit mid-time (BJD)

2,459,317.7500

Long. of periastron (ω)

0.00°

Angular separation (arcsec)

0.12400

Eq. Temperature

2,319K

(2046 °C)

Insolation (S⊕)

4,709.00

Earth = 1.00

Earth Similarity (ESI)

0.112

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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

Lacedelli et al. 2020

Instrument

TESS CCD Array

Publication

2020-12

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-700 b · Rocky Terrestrial 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

Host System: TOI-561

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,342 K — cooler than the Sun (5,778 K)

Estimated Age

16.10 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.843 R☉

Stellar Mass

0.806 M☉

Metallicity [Fe/H]

-0.41

Extended Stellar Properties

Surface gravity (log g)

4.470 dex

Stellar density

1.847 g/cm³

Systemic radial velocity

79.54 km/s

Rotational v·sin i

2.00 km/s

Activity index (log R'HK)

-5.003

Metallicity ratio

[Fe/H]

Distance

85.80 parsec

Light-years 279.84 ly

V-band magnitude

10.25 mag

Voyager-speed travel 4,934,953 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

11.627 mas

Total Proper Motion

124.664 mas/yr

PM Right Ascension

-108.43 mas/yr

PM Declination

-61.51 mas/yr

Galactic Cartesian (pc)

x = -0.845 · y = 0.524 · z = 0.108

Equatorial (J2000)

RA 148.18515° · Dec 6.21610°

Galactic ℓ, b

230.849° · 42.729°

Ecliptic λ, β

148.190° · -6.265°

HTM-20 index

1626683458