Key parameters at a glance
- A radius of 12.80 Earth radii
- A mass of 1,891.00 Earth masses
- Surface gravity around 11.54 g
- An orbital period of 3.312 days
- Semi-major axis 0.0490 AU
- Distance from Earth 51.05 light-years
- Earth Similarity Index 0.438
- Travel time at Voyager 1 speed 900,271 years
Context from the literature
Tau Boötis b, or more precisely Tau Boötis Ab, is an extrasolar planet approximately 51 light-years away. The planet and its host star is one of the planetary systems selected by the International Astronomical Union as part of NameExoWorlds, their public process for giving proper names to exoplanets and their host star. The process involved public nomination and voting for the new names, and the IAU planned to announce the new names in mid-December 2015. However, the IAU annulled the vote as the winning name was judged not to conform with the IAU rules for naming exoplanets.
Excerpted from Wikipedia · full article
tau Boo b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1063of 1771
top 60.0%
This planet
12.80R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | tau Boo b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 12.80 | 11.21 |
| Mass (M⊕) | 1.00 | 1,891.00 | 317.83 |
| Density (g/cm³) | 5.51 | 4.95 | 1.33 |
| Surface Gravity (g) | 1.00 | 11.54 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,891.000 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 1,373.026 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 120136
HIP
HIP 67275
TIC
TIC 72506701
Gaia DR2
Gaia DR2 1244571953471006720
Gaia DR3
Gaia DR3 1244571953471006720
System
tau Boo
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.31 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0490 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
471.730 m/s
Transit mid-time (BJD)
2,453,104.8280
Long. of periastron (ω)
113.40°
Angular separation (arcsec)
3.13000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.438
0 = alien, 1 = Earth-identical
Discovery Paper
Primary reference
Butler et al. 1997Instrument
Hamilton Echelle Spectrograph
Publication
1997-01
Observation locale
Ground
Discovery cohort
Planets confirmed in 1996 at Lick Observatory (4 shown).
Host System: tau Boo
Spectral Class
F-type yellow-white
Effective Temperature
6,466 K — hotter than the Sun (5,778 K)
Estimated Age
2.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.426 R☉
Stellar Mass
1.320 M☉
Metallicity [Fe/H]
0.26
Extended Stellar Properties
Surface gravity (log g)
4.251 dex
Stellar density
0.642 g/cm³
Systemic radial velocity
-16.40 km/s
Rotational v·sin i
14.98 km/s
Rotation period
4.00 days
Activity index (log R'HK)
-4.700
Metallicity ratio
[M/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
63.864 mas
Total Proper Motion
472.360 mas/yr
PM Right Ascension
-467.91 mas/yr
PM Declination
64.69 mas/yr
Galactic Cartesian (pc)
x = -0.851 · y = -0.430 · z = 0.300
Equatorial (J2000)
RA 206.81346° · Dec 17.45716°
Galactic ℓ, b
358.933° · 73.891°
Ecliptic λ, β
197.926° · 26.513°
HTM-20 index
-1979046250
Observation Record
Photometric series
1
RV measurements
3
Stellar spectra
1
Archive notes
5
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