1,714 research outputs found
Observational Constraints on Trojans of Transiting Extrasolar Planets
Theoretical studies predict that Trojans are likely a frequent byproduct of
planet formation and evolution. We present a novel method of detecting Trojan
companions to transiting extrasolar planets which involves comparing the time
of central eclipse with the time of the stellar reflex velocity null. We
demonstrate that this method offers the potential to detect terrestrial-mass
Trojans using existing ground-based observatories. This method rules out Trojan
companions to HD 209458b and HD 149026b more massive than ~13 Earth masses and
\~25 Earth masses at a 99.9% confidence level. Such a Trojan would be
dynamically stable, would not yet have been detected by photometric or
spectroscopic monitoring, and would be unrecognizable from radial velocity
observations alone. We outline the future prospects for this method, and show
that the detection of a "Hot Trojan" of any mass would place a significant
constraint on theories of orbital migration.Comment: 6 pages, 2 figures, 1 table, accepted to ApJL. Added references, new
transiting planets to table; minor correction
Detectability of Oort cloud objects using Kepler
The size distribution and total mass of objects in the Oort Cloud have
important implications to the theory of planets formation, including the
properties of, and the processes taking place in the early solar system. We
discuss the potential of space missions like Kepler and CoRoT, designed to
discover transiting exo-planets, to detect Oort Cloud, Kuiper Belt and main
belt objects by occultations of background stars. Relying on published
dynamical estimates of the content of the Oort Cloud, we find that Kepler's
main program is expected to detect between 0 and ~100 occultation events by
deca-kilometer-sized Oort Cloud objects. The occultations rate depends on the
mass of the Oort cloud, the distance to its "inner edge", and the size
distribution of its objects. In contrast, Kepler is unlikely to find
occultations by Kuiper Belt or main belt asteroids, mainly due to the fact that
it is observing a high ecliptic latitude field. Occultations by Solar System
objects will appear as a photometric deviation in a single measurement,
implying that the information regarding the time scale and light-curve shape of
each event is lost. We present statistical methods that have the potential to
verify the authenticity of occultation events by Solar System objects, to
estimate the distance to the occulting population, and to constrain their size
distribution. Our results are useful for planning of future space-based
exo-planet searches in a way that will maximize the probability of detecting
solar system objects, without hampering the main science goals.Comment: Submitted to ApJL, 5 pages, 1 figur
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