Gregory Laughlin

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This paper outlines astrophysical issues related to the long term fate of the universe. We consider the evolution of planets, stars, stellar populations, galaxies, and the universe itself over time scales which greatly exceed the current age of the universe. Our discussion starts with new stellar evolution calculations which follow the future evolution of(More)
When stars form within small groups (with N⋆ ≈ 100 − 500 members), their circumstellar disks are exposed to relatively little EUV (hν > 13.6 eV) radiation but a great deal of FUV (6 eV < hν < 13.6 eV) radiation (∼ 10 times the local interstellar FUV field) from the most massive stars in the group. This paper calculates the mass loss rates and evaporation(More)
The favored theoretical explanation for giant planet formation – in both our solar system and others – is the core accretion model (although it still has some serious difficulties). In this scenario, planetesimals accumulate to build up planetary cores, which then accrete nebular gas. With current opacity estimates for protoplanetary envelopes, this model(More)
We report the detection of a second exoplanet orbiting the G6V dwarf HD 73526. This second planet has an orbital period of 377 days, putting it in a 2:1 resonance with the previously known exoplanet, the orbital period for which is updated to 188 days. Dynamical modeling of the combined system allows solution for a self-consistent set of orbital elements(More)
Precise Doppler velocity measurments during 13 years at Lick Observatory reveal the presence of two planets orbiting the star 47 UMa. The previously detected inner planet is confirmed by the newer velocities which yield a revised orbital period Pb = 1089.0 ± 2.9 d, M sin i = 2.54 MJUP, and eccentricity eb = 0.061 ± 0.014. The residuals to that(More)
The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its 2-year mission, TESS will employ four wide-field optical(More)
We have computed evolutionary models for extrasolar planets which range in mass from 0.1 MJUP to 3.0 MJUP, and which range in equilibrium temperature from 113 K to 2000 K. We present four sequences of models, designed to show the structural effects of a solid (20 M⊕) core and of internal heating due to the conversion of kinetic to thermal energy at(More)
Near-infrared observations of more than a dozen 'hot-Jupiter' extrasolar planets have now been reported. These planets display a wide diversity of properties, yet all are believed to have had their spin periods tidally spin-synchronized with their orbital periods, resulting in permanent star-facing hemispheres and surface flow patterns that are most likely(More)