83 research outputs found

    Mars: The Next Steps

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    In 1993, the National Aeronautics and Space Administration (NASA) began the Mars Surveyor program to fly small, focused missions to Mars at every launch opportunity (2-year intervals) using the “faster, better, cheaper” approach championed by administrator Dan Goldin. NASA's plans are now under intense scrutiny because of the loss of all spacecraft arriving at Mars within the past six months. Panels commissioned to study the failures have released reports enumerating technical, managerial, and program problems and made recommendations to address these lapses. Recent events also provide an opportunity to reconsider the larger picture of Mars exploration: What are the program's goals within the context of both the scientific community and the society that supports it, and what is the best strategy to achieve those goals

    Remote infrared thermography for boundary layer measurements

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991.Includes bibliographical references (leaves 50-51).by Eric J. Gaidos.M.S

    Paleocosmology : observational constraints on the evolution of galaxies and large-scale structure

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1996.Includes bibliographical references (p. 168-175).by Eric James Gaidos.Ph.D

    Spectroscopy and Photometry of Nearby Young Solar Analogs

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    We present new photometry and spectroscopy of 34 stars from a catalog of 38 nearby (d \u3c 25 pc) G and K dwarfs selected as analogs to the early Sun. We report that the least active star in our sample is also slowly rotating and probably of solar age. Two other stars appear to be evolved objects that have recently acquired angular momentum. A fourth star may be a spectroscopic binary. Many of the other stars belong to previously identified common proper-motion groups. Space motions, lithium abundances, and Ca II emission of these stars suggest ages between 70 and 800 Myr

    Kepler-445, Kepler-446 And The Occurrence Of Compact Multiples Orbiting Mid-M Dwarf Stars

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    We confirm and characterize the exoplanetary systems Kepler-445 and Kepler-446: two mid-M dwarf stars, each with multiple, small, short-period transiting planets. Kepler-445 is a metal-rich ([ Fe/H] = + 0.25 0.10) M4 dwarf with three transiting planets, and Kepler-446 is a metal-poor ([ Fe/H] = -0.30 0.10) M4 dwarf also with three transiting planets. Kepler-445c is similar toGJ 1214b: both in planetary radius and the properties of the host star. The Kepler-446 system is similar to the Kepler-42 system: both are metal-poor with large galactic space velocities and three short-period, likely rocky transiting planets that were initially assigned erroneously large planet-to-star radius ratios. We independently determined stellar parameters from spectroscopy and searched for and fitted the transit light curves for the planets, imposing a strict prior on stellar density in order to remove correlations between the fitted impact parameter and planet-to-star radius ratio for short-duration transits. Combining Kepler-445, Kepler-446, and Kepler-42, and isolating all mid-M dwarf stars observed by Kepler with the precision necessary to detect similar systems, we calculate that 21+ 7 -5 % of mid-M dwarf stars host compact multiples ( multiple planets with periods of less than 10 days) for a wide range of metallicities. We suggest that the inferred planet masses for these systems support highly efficient accretion of protoplanetary disk metals by mid-M dwarf protoplanets.NSF DGE1144152, AST-1005313NASA NAS5-26555NASA Office of Space Science NNX13AC07GAstronom

    M2K: I. A Jovian mass planet around the M3V star HIP79431

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    Doppler observations from Keck Observatory reveal the presence of a planet with Msini of 2.1 Mjup orbiting the M3V star HIP79431. This is the sixth giant planet to be detected in Doppler surveys of M dwarfs and it is one of the most massive planets discovered around an M dwarf star. The planet has an orbital period of 111.7 days and an orbital eccentricity of 0.29. The host star is metal rich, with an estimated [Fe/H] = +0.4. This is the first planet to emerge from our new survey of 1600 M-to-K dwarf stars.Comment: 5 figure
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