Key parameters at a glance
- A radius of 22.75 Earth radii
- A mass of 1,021.19 Earth masses
- Surface gravity around 1.97 g
- An orbital period of 0.981 days
- Semi-major axis 0.0178 AU
- Equilibrium temperature 1,411 K (1138 °C)
- Distance from Earth 201.52 light-years
- Earth Similarity Index 0.075
- Travel time at Voyager 1 speed 3,553,760 years
- Almost certainly tidally locked to its host star given the close orbit
HIP 65 A b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#12of 1771
top 0.6%
This planet
22.75R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HIP 65 A b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 22.75 | 11.21 |
| Mass (M⊕) | 1.00 | 1,021.19 | 317.83 |
| Density (g/cm³) | 5.51 | 0.48 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.97 | 2.53 |
| Insolation (S⊕) | 1.00 | 661.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,021.188 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 937.594 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HIP
HIP 65 A
TIC
TIC 201248411
Gaia DR2
Gaia DR2 4923860051276772608
Gaia DR3
Gaia DR3 4923860051276772608
System
HIP 65
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts roughly 23.5 hours long on a nearly circular orbit at a mean orbital distance of 0.0178 AU.
Transit Fingerprint
Depth
8.200 %
Duration
0.786 h
Impact parameter b
1.169
Rp / R★
0.287000
Transit midpoint (BJD)
2,458,326.1042
Photometric dip
Transit produces a flux drop of 82,000 ppm lasting ≈ 0.79 h.
Extended Orbital Architecture
Planet / star radius ratio
0.287000
Semi-major axis / stellar radius
5.289
Impact parameter (b)
1.169
RV semi-amplitude (K)
753.700 m/s
Transit mid-time (BJD)
2,458,326.1042
Long. of periastron (ω)
291.42°
Angular separation (arcsec)
0.28800
Eq. Temperature
1,411K
(1138 °C)
Insolation (S⊕)
661.00
Earth = 1.00
Earth Similarity (ESI)
0.075
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
Nielsen et al. 2020Instrument
TESS CCD Array
Publication
2020-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2020 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: HIP 65 A
Spectral Class
K-type orange
Effective Temperature
4,590 K — cooler than the Sun (5,778 K)
Estimated Age
4.10 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.724 R☉
Stellar Mass
0.781 M☉
Metallicity [Fe/H]
0.18
Extended Stellar Properties
Surface gravity (log g)
4.611 dex
Stellar density
2.898 g/cm³
Systemic radial velocity
21.04 km/s
Rotational v·sin i
2.50 km/s
Rotation period
13.20 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
16.156 mas
Total Proper Motion
215.055 mas/yr
PM Right Ascension
-202.82 mas/yr
PM Declination
-71.52 mas/yr
Galactic Cartesian (pc)
x = 0.576 · y = 0.002 · z = -0.817
Equatorial (J2000)
RA 0.18561° · Dec -54.83082°
Galactic ℓ, b
317.943° · -60.795°
Ecliptic λ, β
330.679° · -48.655°
HTM-20 index
874778930
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