Observations of the gravitational microlensing event MOA 2003-BLG-32/OGLE 2003-BLG-219 are presented, for which the peak magnification was over 500, the highest yet reported. Continuous observations around the peak enabled a sensitive search for planets orbiting the lens star. No planets were detected. Planets 1.3 times heavier than Earth were excluded from more than 50% of the projected annular region from approximately 2.3 to 3.6 astronomical units surrounding the lens star, Uranus-mass planets were excluded from 0.9 to 8.7 astronomical units, and planets 1.3 times heavier than Saturn were excluded from 0.2 to 60 astronomical units. These are the largest regions of sensitivity yet achieved in searches for extrasolar planets orbiting any star.
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http://dx.doi.org/10.1126/science.1100714 | DOI Listing |
Entropy (Basel)
October 2024
Institute of Space Science INFLPR Subsidiary, Atomiștilor 409, 077125 Măgurele, Romania.
Astrobiology
December 2024
School of Physics and Astronomy, University of Edinburgh, Scotland, UK.
Standard definitions of habitability assume that life requires the presence of planetary gravity wells to stabilize liquid water and regulate surface temperature. Here, the consequences of relaxing this assumption are evaluated. Temperature, pressure, volatile loss, radiation levels, and nutrient availability all appear to be surmountable obstacles to the survival of photosynthetic life in space or on celestial bodies with thin atmospheres.
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November 2024
Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
Astronomers have found more than a dozen planets transiting stars that are 10-40 million years old, but younger transiting planets have remained elusive. The lack of such discoveries may be because planets have not fully formed at this age or because our view is blocked by the protoplanetary disk. However, we now know that many outer disks are warped or broken; provided the inner disk is depleted, transiting planets may thus be visible.
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November 2024
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
Evidence suggests that, when compact objects such as black holes and neutron stars form, they may receive a 'natal kick', during which the stellar remnant gains momentum. Observational evidence for neutron star kicks is substantial, yet is limited for black hole natal kicks, and some proposed black hole formation scenarios result in very small kicks. Here we report that the canonical black hole low-mass X-ray binary (LMXB) V404 Cygni is part of a wide hierarchical triple with a tertiary companion at least 3,500 astronomical units (AU) away from the inner binary.
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October 2024
European Southern Observatory, Garching, Germany.
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