Planet--61 Vir c Essay Example | Topics and Well Written Essays - 1250 words

Planet--61 Vir c - Essay Example The three planets forming the planetary system of 61 vir are vir b, vir c, vir d (table 2). They were discovered by a team of astronomers including Steven S. Vogt, Robert A. Wittenmyer, R. Paul Butler, Simon O’Toole, Gregory W. Henry, Eugenio J. Rivera, Stefano Meschiari, Gregory Laughlin, C. G. Tinney, Hugh R. A. Jones, Jeremy Bailey, Brad D. Carter, and Konstantin Batygin. The data leading to discovery of this planetary system was obtained from W. M. Keck observatory in Hawaii added to the observations made by Anglo-Australian Telescope (AAT) in New South Wales, Australia. The research was conducted in affiliation with National Science Foundation and NASA, who supported the research (Stephens). Table 1: Parameters of star 61 virginis 61 VIR Parameter Parameter Value References Year Stellar Type G5V Takeda et al. 2007 Mass 0.942(-0.029+0.034) solar masses Takeda et al. 2007 Radius 0.98Â ±0.03 solar radius Takeda et al. 2007 Age 8.96 (-3.08+2.76) Gyr Takeda et al. 2007 Distan ce from Solar System 27.8 light years Takeda et al 2007 Planets 3- Vir b, vir c, vir d Vogt et al. 2010 Table 2: Characteristics of planet 61 vir c (Vogt et al., 1366) 61 VIR C CHARACTERISTICS Characteristic Value Distance from its star (Semi major axis) 0.2175 (Â ±0.0001) AU Mass of Planet (M.sin i) 0.0573(Â ±0.0035)MJ Discovery method/date code RV09 Sibling Planets Vir b and Vir d Orbital period 38.012Â ±0.036 days (Epoch JD 2453369.166) 38.021Â ±0.034 days (Keplerian orbital solutions) Eccentricity 0.14 61 VIRGINIS: 61 Viginis or HD 115617, is located at a distance of 28 light years (8.52 parsecs from the solar system, and is a part of the constellation virgo, along with many other stars namely Spica, ? virginis, ?virginis 70 virginis, chi virginis. The constellation virgo can easily be located on the basis of Spica, which is the brightest star of this constellation. Continuing on the curve formed by the seven major stars of ursa major, known as big dipper; to the star Arctur us of bootes constellation; the star spica can be located. The star belongs to the category of GV5 star, i.e. it is a main sequence star of G type while V is indicative of its luminosity. Main sequence refers to the stage of the life of a star. Stars occupying a position on Hertzsprung-Russel plot as a consequence of their absolute levels of brightness and colour index are known as main sequence stars (figure 1). Both of these properties are dependent on the mass of star which in turn is determined by the chemical composition and chemical reactions responsible for energy of the star (Habets and Heintze, 193). Figure 1: Hertzsprung-Russel plot (http://www.bibliotecapleyades.net) Thus the primary feature of a main sequence star is that it is in hydrostatic equilibrium, converting hydrogen in its core to helium by nuclear fusion; while simultaneously increasing in size. They form 91% of the stars known, are also known as dwarf stars in contrast to the rest which are known as white dwar fs (8%) and giants (1%). Our sun is a main sequence star and so is Virginis 61. The main sequence stars are further classified in to spectral classes depending on their temperature and other features such as luminosity and mass. Vir 61 belongs to spectral class G5, i.e. with a surface temperature of 10,000? C, Mass of 0.92 solar mass, luminosity 0.8 solar luminosity and lifespan of 15 billion years. (Habets and Heint