Stellar HostProfile

TOI-521

M3 • 60.94 pc

Records

literature rows

Planets

system count

References

distinct source labels

TIC: TIC 27649847

Approximate color

from effective temperature

Stellar source: Lacedelli et al. 2026 • System source: TICv8

Temperature

3544 K

3439 to 3544

3 values • 3 distinct

Mass

0.42 Msun

0.41 to 0.42

2 values • 2 distinct

Radius

0.42 Rsun

0.42 to 0.42

3 values • 2 distinct

Age

0.80 Gyr

single adopted value

1 values • 1 distinct

Luminosity

-1.60 log(Lsun)

-1.64 to -1.60

2 values • 2 distinct

Distance

60.94 pc

single adopted value

3 values • 1 distinct

Spectral Type

Consistent across records

M3 (1)

Planets

Stable across source rows

Sun

1.0 R☉ baseline

TOI-521

0.42 R☉

Discovery

2025

Period

1.54 days

Radius

1.98 R⊕

Mass

5.30 M⊕

Eq. Temp

794 K

TOI-521 b: A Close-Range Super-Earth Around a Cool Red Dwarf

TOI-521 is an M3 star 199 light-years away, with a reported lower limit of 0.8 billion years of age. Its measurements include 0.42 solar masses, 0.421 solar radii, and a temperature of 3540 K. The star's reported mass estimate is smaller than the Sun's, its reported radius estimate is smaller than the Sun's, and its reported temperature is cooler than the Sun's. One planet orbits this host.

TOI-521 b is a Super-Earth discovered by Transit in 2025. In a transit, a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness, and repeated dips help establish orbital periods. The planet's mass is 5.3 Earth masses, larger than Earth's, and its radius is 1.98 Earth radii, also larger than Earth's. Its orbital period is 1.54 days. The mean density of TOI-521 b is 3.76 g/cm³, 0.683 times Earth's.

Evidence Summary

Rows

Stellar refs

System refs

Distancestable

3 values • 1 distinct

Parallaxstable

3 values • 1 distinct

Temperaturedisputed

3 values • 3 distinct

Massdisputed

2 values • 2 distinct

Radiusdisputed

3 values • 2 distinct

Agestable

1 values • 1 distinct

Luminositydisputed

2 values • 2 distinct

Surface Gravitydisputed

3 values • 3 distinct

Metallicitystable

1 values • 1 distinct

Spectral Typestable

1 values • 1 distinct

ST TEFF	ST MASS	ST RAD	ST AGE	ST LUM	ST SPECTYPE	SY DIST	Stellar Ref	System Ref
3544	0.42	0.42	0.80	-1.60	M3	60.94	Lacedelli et al. 2026	TICv8
3439	—	0.42	—	—	—	60.94	ExoFOP	TICv8
3465	0.41	0.42	—	-1.64	—	60.94	TICv8	TICv8

TOI-521

Adopted host values from one source row

Radius against the Sun

Known planets

TOI-521 b

TOI-521 b: A Close-Range Super-Earth Around a Cool Red Dwarf

Underlying measurements and references