{"content":[{"text":"– 2 –","bbox":{"left":0.479216,"top":0.093224,"width":0.04151199999999999,"height":0.015109999999999998}},{"text":"1.","bbox":{"left":0.42,"top":0.139333,"width":0.017075000000000007,"height":0.015094999999999997}},{"text":"Introduction","bbox":{"left":0.459019,"top":0.139333,"width":0.121033,"height":0.015094999999999997}},{"text":"The ﬁrst successful detection produced by radial velocity surveys of a planet orbiting a \n star occured in 1995 when a near Jupiter-mass planet was found around the main sequence \n star 51 Pegasus (Mayor & Queloz 1995). Subsequent observations veriﬁed the existence of \n the companion and reﬁned its orbital parameters (Marcy & Butler 1995; Marcy et al. 1997). \n By 2007, over 200 planetary systems have been discovered via the radial velocity method \n and the statistics of various properties of the planets have been catalogued (Butler et al. \n 2006)","bbox":{"left":0.117647,"top":0.176103,"width":0.7647250000000001,"height":0.135413}},{"text":"Most radial velocity surveys have been conducted on main sequence stars typically older \n than 1 Gyr. The use of the radial velocity method on younger stars is challenging because \n of increased activity, speciﬁcally in the form of signals caused by star spots. Spots on the \n surface of the star rotate in and out of view of the observer, potentially creating spurious \n radial velocity signatures.","bbox":{"left":0.117647,"top":0.326254,"width":0.7647710000000001,"height":0.09541300000000003}},{"text":"Paulson et al. (2004) looked for planetary companions to stars in the Hyades cluster \n (∼790 Myr). They found activity induced jitter consistent with the empirical relationship \n between activity and radial velocity described in Saar & Donahue (1997). Paulson et al. \n (2004) also found one binary (K = 1152 m s−1) and two candidate binaries with linear \n velocity trends, but no planetary companions. More recently, Paulson & Yelda (2006) ex- \n amined 61 stars in the β Pic moving group (∼12 Myr) and the Ursa Majoris association \n (∼300 Myr) and found no Jupiter mass planets in short period orbits. The authors found \n these results unsurprising, as planetary companions are rare around main sequence stars \n with the small orbital separations (< 0.1 AU) that these surveys were able to probe. They \n measured maximum radial velocity amplitudes of 30-100 m s−1 for targets in Ursa Majoris \n and 250-600 m s−1 for targets in β Pic.","bbox":{"left":0.117646,"top":0.436406,"width":0.764726,"height":0.21571599999999996}},{"text":"These searches were motivated, as is ours, by an interest in understanding the formation \n of both stellar and planetary systems. By probing the youngest stars for planetary compan- \n ions, we can learn at what stage planets form. Since the time scale for the core accretion \n model (Pollack et al. 1996) is longer than formation due to disk instability (Boss 1997), a \n detection of a young planet around a T Tauri star should also provide clues to the formation \n mechanism itself. We can also explore the level of stellar activity in young stars and how \n this can eﬀect our ability to measure radial velocity variations, and therefore detect planets. \n Recently, Setiawan et al. (2007) have reported the detection of a planet around the 100 Myr \n star HD 70573.","bbox":{"left":0.117646,"top":0.66686,"width":0.764725,"height":0.17556499999999997}},{"text":"An additional motivation to search for companions around young stars is to understand \n the origin of the so-called “brown dwarf desert.” As more planetary companions were dis-","bbox":{"left":0.117646,"top":0.857163,"width":0.7646029999999999,"height":0.035109999999999975}}],"images_bbox":[],"images_bbox_not_text_overlap":[]}