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The Struve 1341 binary star system on GALEX sky survey |
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| Observation data Epoch J2000.0 Equinox J2000.0 |
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|---|---|
| Constellation | Ursa Major |
| Struve 1341 A or HD 80607 | |
| Right ascension | 09h 22m 39.7266s |
| Declination | +50° 36′ 13.927″ |
| Apparent magnitude (V) | +9.07 |
| Struve 1341 B or HD 80606 | |
| Right ascension | 09h 22m 37.5679s |
| Declination | +50° 36′ 13.397″ |
| Apparent magnitude (V) | +8.93 |
| Characteristics | |
| Spectral type | G5V / G5V |
| Astrometry | |
| Radial velocity (Rv) | 3.6 / 3.3 km/s |
| Proper motion (μ) | RA: 42.80 / 46.98 mas/yr Dec.: 8.26 / 6.92 mas/yr |
| Parallax (π) | 9.51 / 17.13 mas |
| Distance | 190.41 ly (58.38 pc) |
| Details | |
| HD 80606 | |
| Mass | 0.9 M☉ |
| Temperature | 5370 K |
| Metallicity | 0.43 |
| Age | 7.63 ×109 years |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Database references | |
| SIMBAD | data |
| Extrasolar Planets Encyclopaedia |
data |
Struve 1341 is a binary star system approximately 190 light-years away in the constellation of Ursa Major. Both stars orbit each other at an average distance of 1,200 astronomical units. Both stars are more commonly referred to by their Henry Draper Catalogue numbers: Struve 1341 A is called HD 80607, and Struve 1341 B is called HD 80606. An extrasolar planet has been confirmed to orbit HD 80606 in a highly elliptical orbit.
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Naef's team in 2001 discovered HD 80606 b.[1] As of June 2007, its orbit remains the most eccentric orbit of any extrasolar planet known. It has an eccentricity of 0.9336,[2] comparable to that of Comet Halley in our solar system. The eccentricity may be a result of the Kozai mechanism, which would occur if the planet's orbit is significantly inclined to that of the binary stars. This conclusion is reinforced by the possible detection of a significant misalignment between the planet's orbit and the star's equator, which would be an expected result of the Kozai mechanism.[3]
As a result of this high eccentricity, the planet's distance from its star varies from 0.03 to 0.88 AU. At apoapsis it would receive an insolation similar to that of Earth, while at periapsis the insolation would be around 800 times greater, far more than that experienced by Mercury. This results in extreme temperature variations: observations made when the planet was eclipsed by its star revealed that the temperature rose from 800 K (500 °C / 1000 °F) to 1500 K (1200 °C / 2200 °F) in just six hours around periastron.[4]
In a simulation of a 10 million year span, the planet "sweeps clean" most test particles within 1.75 AU of HD 80606. The 8:1 resonance hollows out another Kirkwood gap at 1.9 AU. There cannot be any habitable planets in this system. Also, observation has ruled out planets heavier than 0.7 Jupiter mass with a period of one year or less.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity |
|---|---|---|---|---|
| b | 4.0 ± 0.3[3] MJ | 0.453 ± 0.015[3] | 111.436 ± 0.003[3] | 0.9336 ± 0.0002[2] |