134 research outputs found
Exoplanet Detection Techniques
We are still in the early days of exoplanet discovery. Astronomers are
beginning to model the atmospheres and interiors of exoplanets and have
developed a deeper understanding of processes of planet formation and
evolution. However, we have yet to map out the full complexity of multi-planet
architectures or to detect Earth analogues around nearby stars. Reaching these
ambitious goals will require further improvements in instrumentation and new
analysis tools. In this chapter, we provide an overview of five observational
techniques that are currently employed in the detection of exoplanets: optical
and IR Doppler measurements, transit photometry, direct imaging, microlensing,
and astrometry. We provide a basic description of how each of these techniques
works and discuss forefront developments that will result in new discoveries.
We also highlight the observational limitations and synergies of each method
and their connections to future space missions.Comment: 24 pages, 19 figures, PPVI proceedings. Appears as 2014, Protostars
and Planets VI, Henrik Beuther, Ralf S. Klessen, Cornelis P. Dullemond, and
Thomas Henning (eds.), University of Arizona Press, Tucson, 914 pp.,
p.715-73
A 4-Planet System Orbiting the K0V Star HD 141399
We present precision radial velocity (RV) data sets from Keck-HIRES and from
Lick Observatory's new Automated Planet Finder Telescope and Levy Spectrometer
on Mt. Hamilton that reveal a multiple-planet system orbiting the nearby,
slightly evolved, K-type star HD 141399. Our 91 observations over 10.5 years
suggest the presence of four planets with orbital periods of 94.35, 202.08,
1070.35, and 3717.35 days and minimum masses of 0.46, 1.36, 1.22, and 0.69
Jupiter masses respectively. The orbital eccentricities of the three inner
planets are small, and the phase curves are well sampled. The inner two planets
lie just outside the 2:1 resonance, suggesting that the system may have
experienced dissipative evolution during the protoplanetary disk phase. The
fourth companion is a Jupiter-like planet with a Jupiter-like orbital period.
Its orbital eccentricity is consistent with zero, but more data will be
required for an accurate eccentricity determination.Comment: 11 pages, 13 figures, To appear in the Astrophysical Journa
Transformation of Statistics in Fractional Quantum Hall Systems
A Fermion to Boson transformation is accomplished by attaching to each
Fermion a tube carrying a single quantum of flux oriented opposite to the
applied magnetic field. When the mean field approximation is made in Haldane's
spherical geometry, the Fermion angular momentum l_F is replaced by
l_B=l_F-(N-1)/2. The set of allowed total angular momentum multiplets is
identical in the two different pictures. The Fermion and Boson energy spectra
in the presence of many body interactions are identical only if the
pseudopotential V (interaction energy as a function of pair angular momentum
L_12) increases as L_12(L_12+1). Similar bands of low energy states occur in
the two spectra if V increases more quickly than this.Comment: 4 pages, 1 figure, poster at ARW in Queenstown, New Zealand (2001
The Fermion-Boson Transformation in Fractional Quantum Hall Systems
A Fermion to Boson transformation is accomplished by attaching to each
Fermion a single flux quantum oriented opposite to the applied magnetic field.
When the mean field approximation is made in the Haldane spherical geometry,
the Fermion angular momentum is replaced by .
The set of allowed total angular momentum multiplets is identical in the two
different pictures. The Fermion and Boson energy spectra in the presence of
many body interactions are identical if and only if the pseudopotential is
``harmonic'' in form. However, similar low energy bands of states with Laughlin
correlations occur in the two spectra if the interaction has short range. The
transformation is used to clarify the relation between Boson and Fermion
descriptions of the hierarchy of condensed fractional quantum Hall states.Comment: 5 pages, 4 figures, submitted to Physica
A Six-Planet System Around the Star HD 34445
We present a new precision radial velocity dataset that reveals a
multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists
of 333 precision radial velocity observations, 56 of which were previously
published, and 277 which are new data from Keck Observatory, Magellan at Las
Campanas Observatory, and the Automated Planet Finder at Lick Observatory.
These data indicate the presence of six planet candidates in Keplerian motion
about the host star with periods of 1057, 215, 118, 49, 677, and 5700 days, and
minimum masses of 0.63, 0.17, 0.1, 0.05, 0.12 and 0.38 Jupiter masses
respectively. The HD 34445 planetary system, with its high degree of
multiplicity, its long orbital periods, and its induced stellar radial velocity
half-amplitudes in the range is fundamentally unlike either our own solar system (in which only
Jupiter and Saturn induce significant reflex velocities for the Sun), or the
Kepler multiple-transiting systems (which tend to have much more compact
orbital configurations)Comment: 10 pages, 11 figure
Conditional Glycosylation in Eukaryotic Cells Using a Biocompatible Chemical Inducer of Dimerization
Preparing Students for Team-Based Care for Vulnerable Populations
Health professionals have an obligation to improve both the health of the individual and the public in a time of scarce resources. The Institute of Medicine (IOM), Healthy People Curriculum Task Force and professional education accreditation standards indicate the need for health care professionals to demonstrate competencies related to community engagement, basic health promotion skills and the ability to work effectively in interprofessional teams. An Interprofessional Course, IPE 413: Developing Care for a Vulnerable Population provides students the opportunity to collaborate to address health needs in cooperation with a community partner. Students work in teams to address the complex health care needs of an individual community member. The one hour elective course is open to students from nursing, occupational therapy, pharmacy, social work, and exercise science. Efforts are underway to explore the possibility of offering this course to medical students. Students are assessed on the knowledge and experience gained through this interprofessional experience using the Team Skills Scale and student reflections. Faculties from each of the disciplines utilize a collaborative model in the instructional design of the course. The content is co-taught and faculty not only role model interprofessional care, but also serve as mentors and resource personnel for the students as they work with their clients
Interstellar Comets from Post-Main Sequence Systems as Tracers of Extrasolar Oort Clouds
Interstellar small bodies are unique probes into the histories of
exoplanetary systems. One hypothesized class of interlopers are "Jurads,"
exo-comets released into the Milky Way during the post-main sequence as the
thermally-pulsing asymptotic giant branch (AGB) host stars lose mass. In this
study, we assess the prospects for the Legacy Survey of Space and Time (LSST)
to detect a Jurad and examine whether such an interloper would be
observationally distinguishable from exo-comets ejected during the (pre-)main
sequence. Using analytic and numerical methods, we estimate the fraction of
exo-Oort Cloud objects that are released from 1-8 solar mass stars during
post-main sequence evolution. We quantify the extent to which small bodies are
altered by the increased luminosity and stellar outflows during the AGB,
finding that some Jurads may lack hypervolatiles and that stellar winds could
deposit dust that covers the entire exo-comet surface. Next, we construct
models of the interstellar small body reservoir for various size-frequency
distribution slopes, characteristic sizes, and the total mass sequestered in
the minor planets of exo-Oort Clouds. Even with the LSST's increased search
volume compared to contemporary surveys, we find that detecting a Jurad is
unlikely but not infeasible given the current understanding of (exo)planet
formation.Comment: 28 pages, 13 figures; accepted to PS
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