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We present spectroscopic measurements of the Rossiter-McLaughlin effect for WASP-148b, the only known hot Jupiter with a nearby warm-Jupiter companion, from the WIYN/NEID and Keck/HIRES instruments. This is one of the first scientific results reported from the newly commissioned NEID spectrograph, as well as the second obliquity constraint for a hot Jupiter system with a close-in companion, after WASP-47. WASP-148b is consistent with being in alignment with the sky-projected spin axis of the host star, with $\lambda=-8^{\circ}.2^{{+8^{\circ}.7}}_{-9^{\circ}.7}$. The low obliquity observed in the WASP-148 system is consistent with the orderly-alignment configuration of most compact multi-planet systems around cool stars with obliquity constraints, including our solar system, and may point to an early history for these well-organized systems in which migration and accretion occurred in isolation, with relatively little disturbance. By contrast, previous results have indicated that high-mass and hot stars appear to more commonly host a wide range of misaligned planets: not only single hot Jupiters, but also compact systems with multiple super-Earths. We suggest that, to account for the high rate of spin-orbit misalignments in both compact multi-planet and isolated-hot-Jupiter systems orbiting high-mass and hot stars, spin-orbit misalignments may be caused by distant giant planet perturbers, which are most common around these stellar types., Comment: 13 pages, 4 figures, accepted for publication in ApJL

NEID is a radial velocity (RV) instrument including an ultra-stabilized fiber-fed spectrograph, installed in 2019 at the 3.5m WIYN telescope at Kitt Peak National Observatory. Accompanying it is a solar feed system built to supply the spectrograph with disk-integrated sunlight. Observing the Sun “as a star” is essential for developing and validating mitigation strategies for RV variations due to stellar activity and instrument systematics, thus enabling more-effective detections of lower-mass exoplanets. In this paper, we will detail the design of the NEID solar feed system and showcase early results addressing NEID systematics and solar RV variability.

The NEID extreme precision radial velocity spectrometer is being commissioned at the WIYN 3.5 meter telescope, Kitt Peak National Observatory, Tucson Arizona. In order to meet the stringent 27 cm per second radial velocity precision, the light to NEID comes from an extremely stable fiber feed, called the NEID Port Adapter, equipped with fast tip-tilt correction. The WIYN telescope vibration environment and the Port Adapter tip-tilt and guiding system are key to achieving the 50 milliarcsecond-level centroiding stability required. Here we describe the servo system performance, along with vibration analysis and mitigation plans. This work would be relevant to upgrade and retrofit efforts as older observatories incorporate low-order wavefront correction to stabilize light to advanced spectrometers and imagers.

Using radial-velocity data from the Habitable-zone Planet Finder, we have measured the mass of the Neptune-sized planet K2-25b, as well as the obliquity of its M4.5-dwarf host star in the 600-800MYr Hyades cluster. This is one of the youngest planetary systems for which both of these quantities have been measured, and one of the very few M dwarfs with a measured obliquity. Based on a joint analysis of the radial velocity data, time-series photometry from the K2 mission, and new transit light curves obtained with diffuser-assisted photometry, the planet's radius and mass are $3.44\pm 0.12 \mathrm{R_\oplus}$ and $24.5_{-5.2}^{+5.7} \mathrm{M_\oplus}$. These properties are compatible with a rocky core enshrouded by a thin hydrogen-helium atmosphere (5% by mass). We measure an orbital eccentricity of $e=0.43 \pm 0.05$. The sky-projected stellar obliquity is $\lambda=3 \pm 16^{\circ}$, compatible with spin-orbit alignment, in contrast to other "hot Neptunes" that have been studied around older stars., Comment: Accepted for publication in AJ, 31 pages, 14 figures

We confirm the planetary nature of a warm Jupiter transiting the early M dwarf TOI-1899, using a combination of available TESS photometry; high-precision, near-infrared spectroscopy with the Habitable-zone Planet Finder; and speckle and adaptive optics imaging. The data reveal a transiting companion on an $\sim29$-day orbit with a mass and radius of $0.66\pm0.07\ \mathrm{M_{J}}$ and $1.15_{-0.05}^{+0.04}\ \mathrm{R_{J}}$, respectively. The star TOI-1899 is the lowest-mass star known to host a transiting warm Jupiter, and we discuss the follow-up opportunities afforded by a warm ($\mathrm{T_{eq}}\sim362$ K) gas giant orbiting an M0 star. Our observations reveal that TOI-1899.01 is a puffy warm Jupiter, and we suggest additional transit observations to both refine the orbit and constrain the true dilution observed in TESS., 24 pages, 5 figures, 3 tables, published in AJ

Solar contamination, due to moonlight and atmospheric scattering of sunlight, can cause systematic errors in stellar radial velocity (RV) measurements that significantly detract from the ~10 cm s−1 sensitivity required for the detection and characterization of terrestrial exoplanets in or near habitable zones of Sun-like stars. The addition of low-level spectral contamination at variable effective velocity offsets introduces systematic noise when measuring velocities using classical mask-based or template-based cross-correlation techniques. Here we present simulations estimating the range of RV measurement error induced by uncorrected scattered sunlight contamination. We explore potential correction techniques, using both simultaneous spectrometer sky fibers and broadband imaging via coherent fiber imaging bundles, that could reliably reduce this source of error to below the photon-noise limit of typical stellar observations. We discuss the limitations of these simulations, the underlying assumptions, and mitigation mechanisms. We also present and discuss the components designed and built into the NEID (NN-EXPLORE Exoplanet Investigations with Doppler spectroscopy) precision RV instrument for the WIYN 3.5 m telescope, to serve as an ongoing resource for the community to explore and evaluate correction techniques. We emphasize that while "bright time" has been traditionally adequate for RV science, the goal of 10 cm s−1 precision on the most interesting exoplanetary systems may necessitate access to darker skies for these next-generation instruments.

The carbon-rich AGB star V Hya is believed to be in the very brief transition phase between the AGB and a planetary nebula (PN). Using HST/STIS, we previously found a high-velocity (> 200 kms−1) jet or blob of gas ejected only a few years ago from near (< 0.3 arcsec or 150 AU) the star (Sahai et al. 2003, Sahai et al. 2016). From multi-epoch high-resolution spectroscopy we found time-variable high-velocity absorption features in the CO 4.6 μm vibration-rotation lines of V Hya (Sahai et al. 2009). Modeling shows that these are produced in compact clumps of outflowing gas with significant radial temperature gradients consistent with strong shocks. Here, we present very high resolution (∼100 milliarcsecond) imaging of the central region of V Hya using the coronagraphic mode of the Gemini Planet Imager (GPI) in the 1 μm band and spectral-spatial imaging of 4.6 μm CO 1-0 transitions using the Phoenix spectrometer. We report the detection of a compact central dust disk from GPI, and molecular emission from the Phoenix observations at relatively larger scales. We discuss models for the central structures in V Hya, in particular disks and outflows, using these and complementary images in the optical and radio.

We present imaging and spectroscopic observations of 6478 Gault, a 6 km diameter inner main-belt asteroid currently exhibiting strong, comet-like characteristics. Three distinct tails indicate that ultra-slow dust (ejection speed 0.15+/-0.05 m/s) was emitted from Gault in separate episodes beginning UT 2018 October 28+/-5 (Tail A), UT 2018 December 31+/-5 (Tail B), and UT 2019 February 10+/-7, with durations of 10 to 20 days. With a mean particle radius 100 micron, the estimated masses of the tails are M_A = 2e7 kg, M_B = 3e6 kg and M_C = 3e5 kg, respectively, and the mass loss rates from the nucleus are 10 to 20 kg/s for Tail A, 2 to 3 kg/s for Tail B and about 0.2 kg/s for Tail C. In its optical colors Gault is more similar to C-type asteroids than to S-types, even though the latter are numerically dominant in the inner asteroid belt. A spectroscopic upper limit to the production of gas is set at 1 kg/s. Discrete emission in three protracted episodes effectively rules out an impact origin for the observed activity. Sublimation driven activity is unlikely given the inner belt orbit and the absence of detectable gas. In any case, sublimation would not easily account for the observed multiple ejections. The closest similarity is between Gault and active asteroid 311P/(2013 P5), an object showing repeated but aperiodic ejections of dust over a 9 month period. While Gault is 10 times larger than 311P/(2013 P5), and the spin-up time to radiation torques is 100 times longer, its properties are likewise most consistent with episodic emission from a body rotating near breakup., 40 pages, 13 Figures

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta, Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overview

Observations of active asteroid P/2017 S5 when near perihelion reveal the ejection of large (0.1 to 10 mm) particles at 0.2 to 2 m/s speeds, with estimated mass-loss rates of a few kg/s. The protracted nature of the mass loss (continuous over 150 days) is compatible with a sublimation origin, meaning that this object is likely an ice-bearing main-belt comet. Equilibrium sublimation of exposed water ice covering as little as 0.1 sq. km can match the data. Observations a year after perihelion show the object in an inactive state from which we deduce a nucleus effective radius 450(+100/-60) m (albedo 0.06+/-0.02 assumed). The gravitational escape speed from a body of this size is just 0.3 m/s, comparable to the inferred ejection speed of the dust. Time-series photometry provides tentative evidence for rapid rotation (lightcurve period 1.4 hour) that may also play a role in the loss of mass and which, if real, is a likely consequence of spin-up by sublimation torques. P/2017 S5 shares both physical and orbital similarities with the split active asteroid pair P/2016 J1-A and J1-B, and all three objects are likely members of the 7 Myr old, collisionally produced, Theobalda family., 15 pages, 6 figures

The NEID spectrometer is an optical (380-930 nm), fiber-fed, precision Doppler spectrometer currently in de- velopment for the WIYN 3.5 m telescope at Kitt Peak National Observatory as part of the NN-EXPLORE partnership. Designed to achieve a radial velocity precision of < 30 cm/s, NEID will be sensitive enough to detect terrestrial-mass exoplanets around low-mass stars. Light from the target stars is focused by the telescope to a bent Cassegrain port at the edge of the primary mirror mechanical support. The specialized NEID “Port Adapter” system is mounted at this bent Cassegrain port and is responsible for delivering the incident light from the telescope to the NEID fibers. In order to provide stable, high-quality images to the science instrument, the Port Adapter houses several sub-components designed to acquire the target stars, correct for atmospheric dis- persion, stabilize the light onto the science fibers, and calibrate the spectrometer by injecting known wavelength sources such as a laser frequency comb. Here we provide an overview of the overall opto-mechanical design and system requirements of the Port Adapter. We also describe the development of system error budgets and test plans to meet those requirements.

NEID is an ultra-stabilized, high-resolution, fiber-fed, spectrometer being built by a multi-institutional team for the 3.5 m WIYN telescope at Kitt Peak National Observatory, with a delivery date in 2019. The instrument is supported by the NN-EXPLORE program, a joint endeavor between NASA and the NSF to provide the exoplanet community with extreme ground-based Doppler radial velocity (RV) measurement capability. NEID's primary science objective is the discovery and characterization of terrestrial mass exoplanets, including follow-up of planets discovered by TESS and other spacecraft missions. Achieving these goals requires a multi-faceted approach that combines a state of the art Doppler instrument with a RV precision goal of 30 cm/s, a significantly improved understanding of the stellar radial velocity signal and intrinsic stellar variability, and large numbers of observations distributed optimally in time following guidelines refined over the past 25 years of RV exoplanet discovery. NEID uses a single-arm white pupil echelle optical design to produce R~100,000 spectra covering the complete wavelength range from 0.38 - 0.92 microns on a single 9k x 9k CCD. The optical bench and optics are stabilized with a state of the art temperature control system that achieves sub-mK stability, and are surrounded by a vacuum chamber that maintains 10^-7 Torr pressure or better. This extreme stability minimizes drift in the optics and optomechanical systems. Light is transfered from the telescope to the spectrometer using fiber-optic feeds that combine circular and octagonal fibers with a ball-lens double scrambler to provide high amounts of radial and azmuthal scrambling that minimize variations in the input illumination. These fibers interface with the WIYN telescope through a sophisticated new instrument port, which will provide atmospheric-dispersion correction and active tip-tilt to ensure precise and repeatable target positioning on the fiber. A three tiered calibration system utilizes a Laser Frequency Comb as the primary wavelength calibrator, while providing a stabilized etalon and ThAr and UNe Hollow-Cathode Lamps as high-reliability backup sources. An integrated exposure meter in the form of a low-resolution spectrometer measures precise chromatic exposure time centroids. A sophisticated data reduction pipeline that builds upon algorithms developed over decades of precision RV spectroscopy will automatically transform raw images and telemetry into RVs and other high-level data products, which will be served to users and the community through a NExScI portal. In this paper, we will provide an overview of the NEID project, including a progress update on the instrument integration and testing. We will also describe the WIYN operations plan, which is built around queue scheduled observations, and detail notional science programs that can be carried out with NEID, including the instrument team's GTO program. Finally, we will briefly discuss the impacts of stellar variability, which currently limit RV measurement precision well shy of the fundamental instrument limit, and which we and others are actively working to better understand and mitigate. Additional papers in this conference will describe the instrument subsystems in more detail.

NEID is a new extreme precision Doppler spectrometer for the WIYN telescope. It is fiber fed and employs a classical white pupil Echelle configuration. NEID has a fiber aperture of only 0.92” on sky in high-resolution mode, and its tight radial velocity error budget resulted in very stringent stability requirements for the input illumination of the spectrograph optics. Consequently, the demands on the fiber injection are challenging. In this paper, we describe the layout and optical design of the injection module, including a broadband, high image quality relay and a high-performance atmospheric dispersion corrector (ADC) across the bandwidth of 380 – 930 nm.

The NEID Port Adapter is the interface between the WIYN 3.5m Telescope and the NEID fiber-fed spectrometer. The spectrometer requires the stellar jitter to be controlled for 90% of the time to within 50 milli-arc seconds for visual magnitudes 12, and 200 milli-arc seconds for V-magnitudes 12-16. The NEID Port Adapter will use an Andor EMCCD with 13 micron pixels, and a tip/tilt piezo stage from nPoint with a lowest resonant mode of 479 Hz. We expect to meet the requirement with a closed-loop rate of 27 Hz. We have data taken at the WIYN telescope consisting of stellar centroids captured at a rate of 108.75 Hz, which we rebin to test the response at lower sampling rates. We present the results of feeding these waveforms into the nPoint controller and measuring the actual response.

We report on the upgraded One Degree Imager (ODI) at the WIYN 3.5 meter telescope at the Kitt Peak Observatory after the focal plane was expanded by an additional seventeen detectors in spring 2015. The now thirty Orthogonal Transfer Array CCD detectors provide a total field of view of 40' x 48' on the sky. The newly added detectors underwent a design revision to mitigate reduced charge transfer efficiency under low light conditions. We discuss the performance of the focal plane and challenges in the photometric calibration of the wide field of view, helped by the addition of telescope baffles. In a parallel project, we upgraded the instrument's three filter arm mechanisms, where a degrading worm-gear mechanism was replaced by a chain drive that is operating faster and with high reliability. Three more filters, a u' band and two narrow band filters were added to the instrument's complement, with two additional narrow band filters currently in procurement (including an H-alpha filter). We review the lessons learned during nearly three years of operating the instrument in the observatory environment and discuss infrastructure upgrades that were driven by ODI's needs., Comment: submitted to SPIE Astronomical Telescopes + Instrumentation conference

We present observations of the interstellar interloper 1I/2017 U1 ('Oumuamua) taken during its 2017 October flyby of Earth. The optical colors B-V = 0.70$\pm$0.06, V-R = 0.45$\pm$0.05, overlap those of the D-type Jovian Trojan asteroids and are incompatible with the ultrared objects which are abundant in the Kuiper belt. With a mean absolute magnitude $H_V$ = 22.95 and assuming a geometric albedo $p_V$ = 0.1, we find an average radius of 55 m. No coma is apparent; we deduce a limit to the dust mass production rate of only $\sim$ 2$\times$10$^{-4}$ kg s$^{-1}$, ruling out the existence of exposed ice covering more than a few m$^2$ of the surface. Volatiles in this body, if they exist, must lie beneath an involatile surface mantle $\gtrsim$0.5 m thick, perhaps a product of prolonged cosmic ray processing in the interstellar medium. The lightcurve range is unusually large at $\sim$2.0$\pm$0.2 magnitudes. Interpreted as a rotational lightcurve the body has semi-axes $\sim$230 m $\times$ 35 m. A $\sim$6:1 axis ratio is extreme relative to most small solar system asteroids and suggests that albedo variations may additionally contribute to the variability. The lightcurve is consistent with a two-peaked period $\sim$8.26 hr but the period is non-unique as a result of aliasing in the data. Except for its unusually elongated shape, 1I/2017 U1 is a physically unremarkable, sub-kilometer, slightly red, rotating object from another planetary system. The steady-state population of similar, $\sim$100 m scale interstellar objects inside the orbit of Neptune is $\sim$10$^4$, each with a residence time $\sim$10 yr., 25 Pages, 2 Tables, 7 Figures; submitted to ApJL

Two key areas of emphasis in contemporary experimental exoplanet science are the detailed characterization of transiting terrestrial planets and the search for Earth analog planets to be targeted by future imaging missions. Both of these pursuits are dependent on an order-of-magnitude improvement in the measurement of stellar radial velocities (RV), setting a requirement on single-measurement instrumental uncertainty of order 10 cm / s. Achieving such extraordinary precision on a high-resolution spectrometer requires thermomechanically stabilizing the instrument to unprecedented levels. We describe the environment control system (ECS) of the NEID spectrometer, which will be commissioned on the 3.5-m WIYN Telescope at Kitt Peak National Observatory in 2019, and has a performance specification of on-sky RV precision

We analyzed data from the first year of a survey for Near Earth Objects (NEOs) that we are carrying out with the Dark Energy Camera (DECam) on the 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory. We implanted synthetic NEOs into the data stream to derive our nightly detection efficiency as a function of magnitude and rate of motion. Using these measured efficiencies and the Solar System absolute magnitudes derived by the Minor Planet Center for the 1377 measurements of 235 unique NEOs detected, we directly derive, for the first time from a single observational data set, the NEO size distribution from 1 km down to 10 meters. We find that there are 10^6.6 NEOs larger than 10 meters. This result implies a factor of ten fewer small NEOs than some previous results, though our derived size distribution is in good agreement with several other estimates., AJ in press

The One Degree Imager-Portal, Pipeline, and Archive (ODI-PPA) is a web science gateway that provides astronomers a modern web interface that acts as a single point of access to their data, and rich computational and visualization capabilities. Its goal is to support scientists in handling complex data sets, and to enhance WIYN Observatory's scientific productivity beyond data acquisition on its 3.5m telescope. ODI-PPA is designed, with periodic user feedback, to be a compute archive that has built-in frameworks including: (1) Collections that allow an astronomer to create logical collations of data products intended for publication, further research, instructional purposes, or to execute data processing tasks (2) Image Explorer and Source Explorer, which together enable real-time interactive visual analysis of massive astronomical data products within an HTML5 capable web browser, and overlaid standard catalog and Source Extractor-generated source markers (3) Workflow framework which enables rapid integration of data processing pipelines on an associated compute cluster and users to request such pipelines to be executed on their data via custom user interfaces. ODI-PPA is made up of several light-weight services connected by a message bus; the web portal built using Twitter/Bootstrap, AngularJS and jQuery JavaScript libraries, and backend services written in PHP (using the Zend framework) and Python; it leverages supercomputing and storage resources at Indiana University. ODI-PPA is designed to be reconfigurable for use in other science domains with large and complex datasets, including an ongoing offshoot project for electron microscopy data.

We report on the implementation of a star tracker camera to improve the telescope pointing and tracking, at the WIYN 3.5 m telescope on Kitt Peak, Arizona. We base the overall concept on a star tracker system developed at the University of Wisconsin and routinely in use now for rocket and high-altitude balloon navigation. This fairly simple system provides pointing and station-keeping information, accurate to a few arcseconds, typically within a second.

The One Degree Imager (ODI) was deployed during the summer of 2012 at the WIYN 3.5m telescope, located on Kitt Peak near Tucson, AZ (USA). ODI is an optical imager designed to deliver atmosphere-limited image quality (≤ 0.4” FWHM) over a one degree field of view, and uses Orthogonal Transfer Array (OTA) detectors to also allow for on-chip tip/tilt image motion compensation. At this time, the focal plane is partially populated (”pODI”) with 13 out of 64 OTA detectors, providing a central scientifically usable field of view of about 24′ x 24′; four of the thirteen detectors are installed at outlying positions to probe image quality at all field angles. The image quality has been verified to be indeed better than 0.4′′ FWHM over the full field when atmospheric conditions allow. Based on over one year of operations, we summarize pODIs performance and lessons learned. As pODI has proven the viability of the ODI instrument, the WIYN consortium is engaging in an upgrade project to add 12 more detectors to the focal plane enlarging the scientifically usable field of view to about 40′ x 40′. A design change in the new detectors has successfully addressed a low light level charge transfer inefficiency.

We present a new lunar scintillometer, LuSci. A simple and accurate way to determine the Ground Layer (GL) turbulence profile is through measuring lunar and solar scintillation. The contribution of the first 10-100 m to the total seeing is usually significant. Measuring the seeing in this GL is important to evaluate sites, especially to set the height of future domes and to translate existing seeing data to higher domes. This holds in particular to Antarctic sites where the GL seeing is dominant, with obvious implications for AO and interferometry. We develop robust methods for turbulence profile restoration from LuSci data, incorporating the effect of lunar phases. We present restored profiles from initial campaigns. We also extract a simple model for the wind profile from the rich information present in the scintillation spectrum.

We present a parametric cost estimate for the Kilometric Optical Interferometer (KOI) in a classical array configuration: 24 telescopes, 4-meter primary mirror, up to 1 km baseline. The parametric cost estimate is based on available cost information from the Magdalena Ridge Observatory (MRO) Interferometer at New Mexico Tech. A Kilometric Optical Interferometer based on a classical array concept has an estimated construction cost between $1B and $3B if it would be built today (2008 dollars and technology). The implication of the estimated construction cost is that cost reductions are critical in the planning phase to bring the cost within a reasonable envelope. Hence we propose to set a budget ceiling that seems feasible given the support to be expected from the scientific community and funding agencies. Given a budget ceiling, a design-to-cost process should be followed. We propose to set a construction phase budget cap of $800M (2008 dollars) for KOI as an initial goal. Narrowing down of the science goals in combination with technology development to reduce cost and technological complexity are the main areas of activities for the next decade. We propose to establish a virtual project office to coordinate these activities.

We report long-baseline interferometric measurements of circumstellar dust around massive evolved stars with the MIDI instrument on the Very Large Telescope Interferometer and provide spectrally dispersed visibilities in the 8-13 micron wavelength band. We also present diffraction-limited observations at 10.7 micron on the Keck Telescope with baselines up to 8.7 m which explore larger scale structure. We have resolved the dust shells around the late type WC stars WR 106 and WR 95, and the enigmatic NaSt1 (formerly WR 122), suspected to have recently evolved from a Luminous Blue Variable (LBV) stage. For AG Car, the protoypical LBV in our sample, we marginally resolve structure close to the star, distinct from the well-studied detached nebula. The dust shells around the two WC stars show fairly constant size in the 8-13 micron MIDI band, with gaussian half-widths of ~ 25 to 40 mas. The compact dust we detect around NaSt1 and AG Car favors recent or ongoing dust formation. Using the measured visibilities, we build spherically symmetric radiative transfer models of the WC dust shells which enable detailed comparison with existing SED-based models. Our results indicate that the inner radii of the shells are within a few tens of AU from the stars. In addition, our models favor grain size distributions with large (~ 1 micron) dust grains. This proximity of the inner dust to the hot central star emphasizes the difficulty faced by current theories in forming dust in the hostile environment around WR stars. Although we detect no direct evidence for binarity for these objects, dust production in a colliding-wind interface in a binary system is a feasible mechanism in WR systems under these conditions., Comment: 21 pages, 4 tables, 13 figures. Accepted for publication in the Astrophysical Journal

During the last few years, considerable effort has been directed towards large-scale (> $1 Billion) missions to detect and characterize earth-like planets around nearby stars, such as the Terrestrial Planet Finder Interferometer and Darwin missions. However, technological issues such as formation flying, cryocooling, obtaining sufficient null depth for broadband signals, and control of systematic noise sources will likely prevent these missions from entering Phase A until at least the end of the present decade. Futhermore, a large mission like TPF-I will also need the endorsement of the next Astronomical Decadal Survey to obtain a Phase A start in the next decade. Thus, given the present circumstances, we can expect TPF-I to launch no earlier than about 2020 or even as late as 2025. Presently more than 168 planets have been discovered by precision radial velocity survey techniques, and little is known about the majority of them. A simplified nulling interferometer operating in the near- to mid-infrared (e.g. ~ 3-8 microns), like the Fourier Kelvin Stellar Interferometer (FKSI), can characterize the atmospheres of a large sample of the known planets. Many other scientific problems can be addressed with a system like FKSI, including the imaging of debris disks, active galactic nuclei, and low mass companions around nearby stars. We discuss the rationale, both scientific and technological, for a competed mission in the $450-600 Million range, of which FKSI is an example. Such a mission is essential to develop our community and keep the larger community, including young scientists, engaged in the long-term effort towards the detection of Earth-like planets.

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging and nulling interferometer for the near infrared to mid-infrared spectral region (3-8 microns). FKSI is a scientific and technological pathfinder to TPF/DARWIN as well as SPIRIT, SPECS, and SAFIR. It will also be a high angular resolution system complementary to JWST. There are four key scientific issues the FKSI mission is designed to address. First, we plan to characterize the atmospheres of the known extra-solar giant planets. Second, we will explore the morphology of debris disks to look for resonant structures to find and characterize extrasolar planets. Third, we will observe young stellar systems to understand their evolution and planet forming potential, and study circumstellar material around a variety of stellar types to better understand their evolutionary state. Finally, we plan to measure detailed structures inside active galactic nuclei. We report results of simulation studies of the imaging capabilities of the FKSI with various configurations of two to five telescopes including the effects of thermal noise and local and exozodiacal dust emission. We also report preliminary results from our symmetric Mach-Zehnder nulling testbed.

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for a nulling interferometer for the near-to-mid-infrared spectral region (3-8µm). FKSI is conceived as a scientific and technological precursor to TPF. The scientific emphasis of the mission is on the evolution of protostellar systems, from just after the collapse of the precursor molecular cloud core, through the formation of the disk surrounding the protostar, the formation of planets in the disk, and eventual dispersal of the disk material. FKSI will answer key questions about extrasolar planets: Σ What are the characteristics of the known extrasolar giant planets? Σ What are the characteristics of the extrasolar zodiacal clouds around nearby stars? Σ Are there giant planets around classes of stars other than those already studied? We present preliminary results of a detailed design study of the FKSI. Using a nulling interferometer configuration, the optical system consists of two 0.5m telescopes on a 12.5m boom feeding a Mach-Zender beam combiner with a fiber wavefront error reducer to produce a 0.01% null of the central starlight. With this system, planets around nearby stars can be detected and characterized using a combination of spectral and spatial resolution.