About the Book
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 90. Chapters: 107 Piscium, 111 Tauri, 12 Ophiuchi, 14 Herculis, 1RXS J160929.1 210524, 2 Aurigae, 36 Arietis, 36 Ophiuchi, 41 G. Arae, 51 Aurigae, 54 Piscium, 61 Cygni, 63 Aurigae, 66 Aurigae, 70 Ophiuchi, 83 Leonis, 85 Pegasi, AB Pictoris, Alpha Centauri, BD+14 4559, BD+20 1790, BD-08 2823, BD-17 63, BD -19 733, BO Microscopii, Chi Draconis, Delta Cygni, Delta Trianguli, Delta Virginis, DE Bootis, Epsilon Eridani, Epsilon Indi, Eta Cassiopeiae, Gliese 146, Gliese 167, Gliese 169, Gliese 250, Gliese 320, Gliese 349, Gliese 40, Gliese 453, Gliese 481, Gliese 505, Gliese 532, Gliese 546, Gliese 556, Gliese 570, Gliese 604, Gliese 615, Gliese 667, Gliese 673, Gliese 688, Gliese 69, Gliese 710, Gliese 775, Gliese 783, Gliese 818, Gliese 833, Gliese 86, Gliese 868, Gliese 892, Gliese 898, Gliese 902, Groombridge 1618, GSC 02652-01324, Habitability of orange dwarf systems, HAT-P-11, HAT-P-3, HD 101930, HD 102195, HD 103197, HD 104067, HD 113538, HD 114386, HD 114783, HD 125595, HD 128311, HD 130322, HD 158633, HD 162020, HD 164604, HD 164922, HD 170657, HD 175167, HD 181433, HD 189733, HD 192263, HD 20868, HD 215497, HD 216770, HD 221148, HD 27894, HD 35519, HD 37605, HD 40307, HD 40325, HD 41004, HD 45652, HD 4628, HD 53143, HD 69830, HD 73267, HD 7924, HD 83443, HD 85390, HD 85512, HD 87883, HD 92945, HD 93083, HD 97658, HD 99109, HIP 5158, HIP 70849, HR 1614, HR 511, HR 5256, HR 6806, HR 753, HR 7722, HR 857, HR 9038, K-type main-sequence star, Kappa2 Apodis, Lupus-TR-3, OGLE-2003-BLG-235/MOA-2003-BLG-53, P Eridani, Sigma2 Ursae Majoris, Sigma Draconis, SZ Crateris, Theta Aurigae, TW Hydrae, TW Piscis Austrini, WASP-10, WASP-11/HAT-P-10, WASP-2, Wolf 635, Xi Bootis, XO-2 (star), Zeta Herculis. Excerpt: Epsilon Eridani ( Eri, Eridani) is a star in the southern constellation Eridanus, along a declination 9.46 south of the celestial equator. This allows the star to be viewed from most of the Earth's surface. At a distance of 10.5 light years (ly), it has an apparent magnitude of 3.73. It is the third closest of the individual stars or star systems visible to the unaided eye and was the closest star known to host a planet until the discovery of Alpha Centauri Bb. Its age is estimated at less than a billion years. Because of its youth, Epsilon Eridani has a higher level of magnetic activity than the present-day Sun, with a stellar wind 30 times as strong. Its rotation period is 11.2 days at the equator. Epsilon Eridani is smaller and less massive than the Sun, and has a comparatively lower level of elements heavier than helium. Astronomers categorize it as a main-sequence star of spectral class K2, which means that energy generated at the core through nuclear fusion of hydrogen is emitted from the surface at a temperature of about 5,000 K, giving the star an orange hue. The motion of this star along the line of sight to the Earth, known as the radial velocity, has been regularly observed for more than twenty years. Periodic changes in this data yielded evidence of a giant planet orbiting Epsilon Eridani, making it one of the nearest extrasolar system with a candidate exoplanet. This object, Epsilon Eridani b, was formally announced in 2000 by a team of astronomers led by Artie Hatzes. Current data indicate that this planet orbits with a period of about 7 years at a mean separation of 3.4 astronomical units (AU), where 1 AU is the mean distance between the Earth and the Sun. Although this discovery has been controversial because of the amount of background noise in the radial velocity data, many astronomers now regard the planet as confirmed. The system includes two belts of rocky asteroids: one at about 3 AU and a second at about 20 AU, whose structure may be maint
