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Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Draco |
A | |
Right ascension | 19h 07m 14.0376s[1] |
Declination | +49° 18′ 59.091″[1] |
Apparent magnitude (V) | 11.41 |
B | |
Right ascension | ~19h 07m 14s[2] |
Declination | ~+49° 18′ 59″[2] |
Characteristics | |
A | |
Spectral type | G0V[3] |
Apparent magnitude (B) | ~12.030[4] |
Apparent magnitude (V) | 11.411±0.005[4] |
Apparent magnitude (I) | 11.07[2] |
Apparent magnitude (Z) | 11.04[2] |
Apparent magnitude (J) | 10.232±0.020[5] |
Apparent magnitude (H) | 9.920±0.026[5] |
Apparent magnitude (K) | 9.846±0.022[5] |
Variable type | Planetary transit[3] |
B | |
Spectral type | K[2] |
Apparent magnitude (I) | 14.73[2] |
Apparent magnitude (Z) | 14.47[2] |
Astrometry | |
Proper motion (μ) | RA: 5.434(15) mas/yr[1] Dec.: 1.572(16) mas/yr[1] |
Parallax (π) | 4.6308 ± 0.0116 mas[1] |
Distance | 704 ± 2 ly (215.9 ± 0.5 pc) |
Details | |
A | |
Mass | 1.05[2] M☉ |
Radius | 1.000+0.036 −0.033[6] R☉ |
Temperature | 5850±50[6] K |
Metallicity | −0.15±0.1[6] |
Age | 5.1+2.7 −2.3×109[6] years |
B | |
Mass | 0.67[2] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
GSC 03549-02811 (sometimes referred to as Kepler-1, or either TrES-2A or TrES-2 parent star in reference to its exoplanet TrES-2b)[7] is a binary star containing a yellow main-sequence star similar to the Sun. This star is located approximately 750 light-years away in the constellation of Draco. The apparent magnitude of this star is 11.41, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night. The age of this star is about 5 billion years.[4]
In 2006 the exoplanet TrES-2b was discovered by the TrES program using the transit method. It is also within the field of view of the previously operational Kepler Mission planet-hunter spacecraft.[3] This system continues to be studied by other projects and the parameters are continuously improved.[6] The planet orbits the primary star.[2]
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 1.199(52) MJ | 0.03555(75) | 2.4706133738(187) | 0 (assumed) | 83.908(9)° | 1.189(25) RJ |
Though TrES-2b is currently the darkest known exoplanet, reflecting less than 1 percent of local sunlight, it shows a faint red glow. This is because its surface is 1,100 °C, it is so hot that it glows red. It is assumed to be tidally locked to its parent star.[9]
In 2008 a study was undertaken of fourteen stars with exoplanets that were originally discovered using the transit method through relatively small telescopes. These systems were re-examined with the 2.2M reflector telescope at the Calar Alto Observatory in Spain. This star system, along with two others, was determined to be a previously unknown binary star system. The previously unknown secondary star is a dim magnitude 15 K-type star separated by about 232 AU from the primary, appearing offset from the primary by about one arc second in the images. This discovery resulted in a significant recalculation of parameters for both the planet and the primary star.[2]
In March 2009 NASA launched the Kepler spacecraft. This spacecraft was a dedicated mission to discover extrasolar planets by the transit method from solar orbit. In April 2009 the project released the first light images from the spacecraft and TrES-2b was one of two objects highlighted in these images. Although TrES-2b is not the only known exoplanet in the field of view of this spacecraft it is the only one identified in the first-light images. This object is important for calibration and check-out.[10]