16h58m08.85s, +25° 44′ 38.97″Gliese 649 is a small star with an orbiting exoplanet in the constellation Hercules. It has an apparent visual magnitude of 9.7,[3] which is too faint to be seen with the naked eye. The system is located at a distance of 33.9 light years based on parallax, and is drifting further away with a radial velocity of 3.8 km/s.[2]
This is an M-type main-sequence star, a red dwarf, with a stellar classification of M1.0V.[3] It has 52% of the mass of the Sun and 53% of the Sun's girth. In the visible light band, the star is radiating 4.4% of the luminosity of the Sun from its photosphere at an effective temperature of 3,621 K.[4] It is spinning slowly with a rotation period of 24.9 days.[3]
A Saturn-mass planet was detected around the red dwarf star by J. A. Johnson and associates in 2010.[7] It has a minimum mass 32.8% of Jupiter's mass and is located 1.15 astronomical units from its star in eccentric orbit (e=0.3). Assuming a luminosity of 4.5% that of the Sun, the habitable zone is located at 0.21 AU, thus the planet should be as cold as if it were located at 5.5 AU from a Solar-like star. Also accounting for different periastron and apastron positions of 0.8 and 1.49 AU respectively, the planet could likely show seasonal temperature changes.
Using results from the Herschel Space Observatory survey of 21 late-type stars carried out in 2010, a debris disk was discovered between approximately 6 and 30 AU. The disk was not detected at 22μm by NASA's Wide-field Infrared Survey Explorer so therefore it is likely to be below 100 Kelvin and similar to the Kuiper belt. The disk was marginally resolved, appearing very asymmetric, and so is probably consistent with being closer to edge-on, rather than face-on, in its inclination.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥0.258+0.023 −0.022 MJ |
1.112+0.035 −0.037 |
600.1±1.7 | 0.083+0.068 −0.055 |
— | — |
| Kuiper belt | ~6–~30 AU | ~45-90° | — | |||
|
| |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||||
| Stars |
| ||||||||||||
| |||||||||||||
| |||||||||||||
| |||||||||||||
| Galaxies |
| ||||||||||||
| |||||||||||||
| |||||||||||||
