Commentary on the History of Public Archaeology at Strawbery Banke, Portsmouth, New Hampshire

This commentary reflects on the ways Strawbery Banke Museum archaeology was affected by, and in turn, influenced the field of historical archaeology. It can be argued that in the late 1960s urban historical archaeology got its start in Portsmouth, New Hampshire. The stories and narrative histories told in these articles are essential to the success of the Strawbery Banke archaeology program, as they reach to the heart of the importance the Portsmouth community attaches to this place. The process of community building has always been at work in Portsmouth and has been what makes Strawbery Banke the museum that it is today. The story of public archaeology and its development at Strawbery Banke discussed in these articles has been a key part of its institutional history

Exploratory Pollen Analysis of the Ditch of the 1665 Turf Fort, Jamestown, Virginia

Pollen analysis of subsoil, slopewash, episodic fill, plowzone, and archaeological backdirt deposits in a core from a ditch associated with the 1665 Turf (earthwork) Fort at Jamestown, Virginia, record bare, slightly weedy local conditions around 17th-century artisan dwellings on the Jamestown waterfront and register the Virginia forest in the background before construction of the fort. Goosefoot dominated the earthwork slope; close relatives of the goldenrods were initially the most prominent plants in the open-ditch period. Pollen percolation rates adjusted for plowing and applied to ragweed-type (Ambrosia-type) percentages suggest that cultivation over the ditch began ca. 1729. Cultural matrix depostition, slopewash, and pollen percolation were crticial to the preservation of this record, and serve to emphasize the importance of evaluating pollen record formation processes in cultural landscape studies

Radiative Transfer for Exoplanet Atmospheres

Remote sensing of the atmospheres of distant worlds motivates a firm understanding of radiative transfer. In this review, we provide a pedagogical cookbook that describes the principal ingredients needed to perform a radiative transfer calculation and predict the spectrum of an exoplanet atmosphere, including solving the radiative transfer equation, calculating opacities (and chemistry), iterating for radiative equilibrium (or not), and adapting the output of the calculations to the astronomical observations. A review of the state of the art is performed, focusing on selected milestone papers. Outstanding issues, including the need to understand aerosols or clouds and elucidating the assumptions and caveats behind inversion methods, are discussed. A checklist is provided to assist referees/reviewers in their scrutiny of works involving radiative transfer. A table summarizing the methodology employed by past studies is provided.Comment: 7 pages, no figures, 1 table. Filled in missing information in references, main text unchange

Investigations of three, four, and five-particle exit channels of levels in light nuclei created using a 9C beam

The interactions of a E/A=70-MeV 9C beam with a Be target was used to populate levels in Be, B, and C isotopes which undergo decay into many-particle exit channels. The decay products were detected in the HiRA array and the level energies were identified from their invariant mass. Correlations between the decay products were examined to deduce the nature of the decays, specifically to what extent all the fragments were created in one prompt step or whether the disintegration proceeded in a sequential fashion through long-lived intermediate states. In the latter case, information on the spin of the level was also obtained. Of particular interest is the 5-body decay of the 8C ground state which was found to disintegrate in two steps of two-proton decay passing through the 6Beg.s. intermediate state. The isobaric analog of 8Cg.s. in 8B was also found to undergo two-proton decay to the isobaric analog of 6Beg.s. in 6Li. A 9.69-MeV state in 10C was found to undergo prompt 4-body decay to the 2p+2alpha exit channel. The two protons were found to have a strong enhancementin the diproton region and the relative energies of all four p-alpha pairs were consistent with the 5Lig.s. resonance

MESS (Multi-purpose Exoplanet Simulation System): A Monte Carlo tool for the statistical analysis and prediction of exoplanets search results

The high number of planet discoveries made in the last years provides a good sample for statistical analysis, leading to some clues on the distributions of planet parameters, like masses and periods, at least in close proximity to the host star. We likely need to wait for the extremely large telescopes (ELTs) to have an overall view of the extrasolar planetary systems. In this context it would be useful to have a tool that can be used for the interpretation of the present results,and also to predict what the outcomes would be of the future instruments. For this reason we built MESS: a Monte Carlo simulation code which uses either the results of the statistical analysis of the properties of discovered planets, or the results of the planet formation theories, to build synthetic planet populations fully described in terms of frequency, orbital elements and physical properties. They can then be used to either test the consistency of their properties with the observed population of planets given different detection techniques or to actually predict the expected number of planets for future surveys. In addition to the code description, we present here some of its applications to actually probe the physical and orbital properties of a putative companion within the circumstellar disk of a given star and to test constrain the orbital distribution properties of a potential planet population around the members of the TW Hydrae association. Finally, using in its predictive mode, the synergy of future space and ground-based telescopes instrumentation has been investigated to identify the mass-period parameter space that will be probed in future surveys for giant and rocky planetsComment: 14 pages, 16 figure

Disequilibrium Carbon, Oxygen, and Nitrogen Chemistry in the Atmospheres of HD 189733b and HD 209458b

We have developed 1-D photochemical and thermochemical kinetics and diffusion models for the transiting exoplanets HD 189733b and HD 209458b to study the effects of disequilibrium chemistry on the atmospheric composition of "hot Jupiters." Here we investigate the coupled chemistry of neutral carbon, hydrogen, oxygen, and nitrogen species, and we compare the model results with existing transit and eclipse observations. We find that the vertical profiles of molecular constituents are significantly affected by transport-induced quenching and photochemistry, particularly on cooler HD 189733b; however, the warmer stratospheric temperatures on HD 209458b can help maintain thermochemical equilibrium and reduce the effects of disequilibrium chemistry. For both planets, the methane and ammonia mole fractions are found to be enhanced over their equilibrium values at pressures of a few bar to less than a mbar due to transport-induced quenching, but CH4 and NH3 are photochemically removed at higher altitudes. Atomic species, unsaturated hydrocarbons (particularly C2H2), some nitriles (particularly HCN), and radicals like OH, CH3, and NH2 are enhanced overequilibrium predictions because of quenching and photochemistry. In contrast, CO, H2O, N2, and CO2 more closely follow their equilibrium profiles, except at pressures < 1 microbar, where CO, H2O, and N2 are photochemically destroyed and CO2 is produced before its eventual high-altitude destruction. The enhanced abundances of HCN, CH4, and NH3 in particular are expected to affect the spectral signatures and thermal profiles HD 189733b and other, relatively cool, close-in transiting exoplanets. We examine the sensitivity of our results to the assumed temperature structure and eddy diffusion coefficientss and discuss further observational consequences of these models.Comment: 40 pages, 16 figures, accepted for publication in Astrophysical Journa

Ground-state properties of H 5 from the He 6 (d, He 3) H 5 reaction

We have studied the ground state of the unbound, very neutron-rich isotope of hydrogen H5, using the He6(d,He3)H5 reaction in inverse kinematics at a bombarding energy of E(He6)=55A MeV. The present results suggest a ground-state resonance energy ER=2.4±0.3 MeV above the H3+2n threshold, with an intrinsic width of Γ=5.3±0.4 MeV in the H5 system. Both the resonance energy and width are higher than those reported in some, but not all previous studies of H5. The previously unreported He6(d,t)Heg.s.5 reaction is observed in the same measurement, providing a check on the understanding of the response of the apparatus. The data are compared to expectations from direct two-neutron and dineutron decay. The possibility of excited states of H5 populated in this reaction is discussed using different calculations of the He6→H5+p spectroscopic overlaps from shell-model and ab initio nuclear-structure calculations

Submillimeter Array Observations of the RX J1633.9-2442 Transition Disk: Evidence for Multiple Planets in the Making

We present continuum high resolution Submillimeter Array (SMA) observations of the transition disk object RX J1633.9-2442, which is located in the Ophiuchus molecular cloud and has recently been identified as a likely site of ongoing giant planet formation. The observations were taken at 340 GHz (880 micron) with the SMA in its most extended configuration, resulting in an angular resolution of 0.3" (35 AU at the distance of the target). We find that the disk is highly inclined (i ~50 deg) and has an inner cavity ~25 AU in radius, which is clearly resolved by our observations. We simultaneously model the entire optical to millimeter wavelength spectral energy distribution (SED) and SMA visibilities of RX J1633.9-2442 in order to constrain the structure of its disk. We find that an empty cavity ~25 AU in radius is inconsistent with the excess emission observed at 12, 22, and 24 micron. Instead, the mid-IR excess can be modeled by either a narrow, optically thick ring at ~10 AU or an optically thin region extending from ~7 AU to ~25 AU. The inner disk (r < 5 AU) is mostly depleted of small dust grains as attested by the lack of detectable near-IR excess. We also present deep Keck aperture masking observations in the near-IR, which rule out the presence of a companion up to 500 times fainter than the primary star (in K-band) for projected separations in the 5-20 AU range. We argue that the complex structure of the RX J1633.9-2442 disk is best explained by multiple planets embedded within the disk. We also suggest that the properties and incidence of objects such as RX J1633.9-2442, T Cha, and LkCa 15 (and those of the companions recently identified to these two latter objects) are most consistent with the runaway gas accretion phase of the core accretion model, when giant planets gain their envelopes and suddenly become massive enough to open wide gaps in the disk.Comment: Accepted for publication in Ap

The PTF Orion Project: a Possible Planet Transiting a T-Tauri Star

We report observations of a possible young transiting planet orbiting a previously known weak-lined T-Tauri star in the 7-10 Myr old Orion-OB1a/25-Ori region. The candidate was found as part of the Palomar Transient Factory (PTF) Orion project. It has a photometric transit period of 0.448413 +- 0.000040 days, and appears in both 2009 and 2010 PTF data. Follow-up low-precision radial velocity (RV) observations and adaptive optics imaging suggest that the star is not an eclipsing binary, and that it is unlikely that a background source is blended with the target and mimicking the observed transit. RV observations with the Hobby-Eberly and Keck telescopes yield an RV that has the same period as the photometric event, but is offset in phase from the transit center by approximately -0.22 periods. The amplitude (half range) of the RV variations is 2.4 km/s and is comparable with the expected RV amplitude that stellar spots could induce. The RV curve is likely dominated by stellar spot modulation and provides an upper limit to the projected companion mass of M_p sin i_orb < 4.8 +- 1.2 M_Jup; when combined with the orbital inclination, i orb, of the candidate planet from modeling of the transit light curve, we find an upper limit on the mass of the planetary candidate of M_p < 5.5 +- 1.4 M_Jup. This limit implies that the planet is orbiting close to, if not inside, its Roche limiting orbital radius, so that it may be undergoing active mass loss and evaporation.Comment: Corrected typos, minor clarifications; minor updates/corrections to affiliations and bibliography. 35 pages, 10 figures, 3 tables. Accepted to Ap

Exoplanet Characterization and the Search for Life

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces with spectroscopy. Rocky planets within their star's habitable zones have the highest priority, as these have the potential to harbor life. Our science goal is to find and characterize all nearby exoplanets; this requires that we measure the mass, orbit, and spectroscopic signature of each one at visible and infrared wavelengths. The techniques for doing this are at hand today. Within the decade we could answer long-standing questions about the evolution and nature of other planetary systems, and we could search for clues as to whether life exists elsewhere in our galactic neighborhood.Comment: 7 pages, 2 figures, submitted to Astro2010 Decadal Revie