Key parameters at a glance
- A radius of 2.54 Earth radii
- A mass of 7.40 Earth masses
- Surface gravity around 1.15 g
- An orbital period of 7.332 days
- Semi-major axis 0.0694 AU
- Equilibrium temperature 799 K (526 °C)
- Distance from Earth 227.77 light-years
- Earth Similarity Index 0.318
- Travel time at Voyager 1 speed 4,016,742 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-1648 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1117of 1978
top 56.4%
This planet
2.54R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-1648 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.54 | 11.21 |
| Mass (M⊕) | 1.00 | 7.40 | 317.83 |
| Density (g/cm³) | 5.51 | 2.49 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.15 | 2.53 |
| Insolation (S⊕) | 1.00 | 27.40 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 7.400 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 376353509
Gaia DR2
Gaia DR2 540977282990133888
Gaia DR3
Gaia DR3 540977282990133888
System
TOI-1648
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 7.33 Earth days (2.0% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0694 AU.
Transit Fingerprint
Depth
0.089 %
Duration
1.540 h
Impact parameter b
0.736
Rp / R★
0.028700
Transit midpoint (BJD)
2,459,925.3431
Photometric dip
Transit produces a flux drop of 893 ppm lasting ≈ 1.54 h.
Extended Orbital Architecture
Planet / star radius ratio
0.028700
Semi-major axis / stellar radius
26.400
Impact parameter (b)
0.736
RV semi-amplitude (K)
2.830 m/s
Transit mid-time (BJD)
2,459,925.3431
Long. of periastron (ω)
286.00°
Angular separation (arcsec)
0.99400
Eq. Temperature
799K
(526 °C)
Insolation (S⊕)
27.40
Earth = 1.00
Earth Similarity (ESI)
0.318
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
Carleo et al. 2025Instrument
TESS CCD Array
Publication
2025-11
Observation locale
Space
Discovery cohort
Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-1648
Spectral Class
K-type orange
Effective Temperature
4,850 K — cooler than the Sun (5,778 K)
Estimated Age
5.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.810 R☉
Stellar Mass
0.830 M☉
Metallicity [Fe/H]
0.20
Extended Stellar Properties
Surface gravity (log g)
4.500 dex
Stellar density
1.823 g/cm³
Systemic radial velocity
-32.18 km/s
Activity index (log R'HK)
-4.950
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
14.291 mas
Total Proper Motion
17.205 mas/yr
PM Right Ascension
16.32 mas/yr
PM Declination
5.43 mas/yr
Galactic Cartesian (pc)
x = 0.249 · y = 0.253 · z = 0.935
Equatorial (J2000)
RA 45.40118° · Dec 69.22992°
Galactic ℓ, b
134.075° · 9.224°
Ecliptic λ, β
67.579° · 49.237°
HTM-20 index
-1011154072
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