Key parameters at a glance
- A radius of 3.82 Earth radii
- A mass of 30.30 Earth masses
- Surface gravity around 2.08 g
- An orbital period of 0.883 days
- Semi-major axis 0.0171 AU
- Equilibrium temperature 1,722 K (1449 °C)
- Distance from Earth 978.93 light-years
- Earth Similarity Index 0.126
- Travel time at Voyager 1 speed 17,263,392 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-3261 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#54of 1978
top 2.7%
This planet
3.82R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-3261 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 3.82 | 11.21 |
| Mass (M⊕) | 1.00 | 30.30 | 317.83 |
| Density (g/cm³) | 5.51 | 3.00 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.08 | 2.53 |
| Insolation (S⊕) | 1.00 | 1,466.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 30.300 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 358070912
Gaia DR2
Gaia DR2 4640654168385886592
Gaia DR3
Gaia DR3 4640654168385886592
System
TOI-3261
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts roughly 21.2 hours long on a nearly circular orbit at a mean orbital distance of 0.0171 AU.
Transit Fingerprint
Depth
0.207 %
Duration
1.618 h
Impact parameter b
0.170
Rp / R★
0.041100
Transit midpoint (BJD)
2,459,112.4004
Photometric dip
Transit produces a flux drop of 2,068 ppm lasting ≈ 1.62 h.
Extended Orbital Architecture
Planet / star radius ratio
0.041100
Semi-major axis / stellar radius
4.333
Impact parameter (b)
0.170
RV semi-amplitude (K)
22.100 m/s
Transit mid-time (BJD)
2,459,112.4004
Long. of periastron (ω)
0.00°
Angular separation (arcsec)
0.05710
Eq. Temperature
1,722K
(1449 °C)
Insolation (S⊕)
1,466.00
Earth = 1.00
Earth Similarity (ESI)
0.126
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. 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
Nabbie et al. 2024Instrument
TESS CCD Array
Publication
2024-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2024 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-3261
Spectral Class
K-type orange
Effective Temperature
5,068 K — cooler than the Sun (5,778 K)
Estimated Age
6.50 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.849 R☉
Stellar Mass
0.861 M☉
Metallicity [Fe/H]
0.14
Extended Stellar Properties
Surface gravity (log g)
4.190 dex
Stellar density
1.400 g/cm³
Rotational v·sin i
2.83 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
3.303 mas
Total Proper Motion
61.034 mas/yr
PM Right Ascension
50.29 mas/yr
PM Declination
34.59 mas/yr
Galactic Cartesian (pc)
x = 0.191 · y = 0.210 · z = -0.959
Equatorial (J2000)
RA 47.72852° · Dec -73.53197°
Galactic ℓ, b
290.698° · -40.111°
Ecliptic λ, β
315.249° · -74.426°
HTM-20 index
31811661
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