arXiv subjects

B. Scott Gaudi

Publications and source records attributed to B. Scott Gaudi.

At least 127 records · Page 7Linked to original sources

arXiv2017

A survey of eight hot Jupiters in secondary eclipse using WIRCam at CFHT

We present near infrared high-precision photometry for eight transiting hot Jupiters observed during their predicted secondary eclipses. Our observations were carried out using the staring mode of the WIRCam instrument on the Canada-France-Hawaii Telescope (CFHT). We present the observing strategies and data reduction methods which delivered time series photometry with statistical photometric precisionas low as 0.11%. We performed a Bayesian analysis to model the eclipse parameters and systematics simultaneously. The measured planet-to-star flux ratios allowed us to constrain the thermal emission from the day side of these hot Jupiters, as we derived the planet brightness temperatures. Our results combined with previously observed eclipses reveal an excess in the brightness temperatures relative to the blackbody prediction for the equilibrium temperatures of the planets for a wide range of heat redistribution factors. We find a trend that this excess appears to be larger for planets with lower equilibrium temperatures. This may imply some additional sources of radiation, such as reflected light from the host star and/or thermal emission from residual internal heat from the formation of the planet.

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arXiv2017

The Architecture of the GW Ori Young Triple Star System and Its Disk: Dynamical Masses, Mutual Inclinations, and Recurrent Eclipses

We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust orbiting the pre-main sequence hierarchical triple star system GW Ori. A forward-modeling of the ${}^{13}$CO and C${}^{18}$O $J$=2-1 transitions permits a measurement of the total stellar mass in this system, $5.29 \pm 0.09\,M_\odot$, and the circum-triple disk inclination, $137.6 \pm 2.0^\circ$. Optical spectra spanning a 35 year period were used to derive new radial velocities and, coupled with a spectroscopic disentangling technique, revealed that the A and B components of GW Ori form a double-lined spectroscopic binary with a $241.50\pm0.05$ day period; a tertiary companion orbits that inner pair with a $4218\pm50$ day period. Combining the results from the ALMA data and the optical spectra with three epochs of astrometry in the literature, we constrain the individual stellar masses in the system ($M_\mathrm{A} \approx 2.7\,M_\odot$, $M_\mathrm{B} \approx 1.7\,M_\odot$, $M_\mathrm{C} \approx 0.9\,M_\odot$) and find strong evidence that at least one (and likely both) stellar orbital planes are misaligned with the disk plane by as much as $45^\circ$. A $V$-band light curve spanning 30 years reveals several new $\sim$30 day eclipse events 0.1-0.7~mag in depth and a 0.2 mag sinusoidal oscillation that is clearly phased with the AB-C orbital period. Taken together, these features suggest that the A-B pair may be partially obscured by material in the inner disk as the pair approaches apoastron in the hierarchical orbit. Lastly, we conclude that stellar evolutionary models are consistent with our measurements of the masses and basic photospheric properties if the GW Ori system is $\sim$1 Myr old.

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arXiv2017

Variability Properties of 4 Million Sources in the $TESS$ Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey

The Kilodegree Extremely Little Telescope (KELT) has been surveying more than $70\%$ of the celestial sphere for nearly a decade. While the primary science goal of the survey is the discovery of transiting, large-radii planets around bright host stars, the survey has collected more than $10^6$ images, with a typical cadence between $10-30$ minutes, for more than $4$ million sources with apparent visual magnitudes in the approximate range $7<V<13$. Here we provide a catalog of 52,741 objects showing significant large-amplitude fluctuations likely caused by stellar variability and 62,229 objects identified with likely stellar rotation periods. The detected variability ranges in $rms$-amplitude from 3 mmag to 2.3 mag, and the detected periods range from $\sim$0.1 days to $\gtrsim$2000 days. We provide variability upper limits for all other $\sim$4 million sources. These upper limits are principally a function of stellar brightness, but we achieve typical 1$σ$ sensitivity on 30-minute timescales down to $\sim5$ mmag at $V\sim 8$, and down to $\sim43$ mmag at $V\sim 13$. We have matched our catalog to the $TESS$ Input catalog and the AAVSO Variable Star Index to precipitate the follow up and classification of each source. The catalog is maintained as a living database on the Filtergraph visualization portal at the URL https://filtergraph.com/kelt$\_$vars

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arXiv2017

The Science Case for an Extended Spitzer Mission

Although the final observations of the Spitzer Warm Mission are currently scheduled for March 2019, it can continue operations through the end of the decade with no loss of photometric precision. As we will show, there is a strong science case for extending the current Warm Mission to December 2020. Spitzer has already made major impacts in the fields of exoplanets (including microlensing events), characterizing near Earth objects, enhancing our knowledge of nearby stars and brown dwarfs, understanding the properties and structure of our Milky Way galaxy, and deep wide-field extragalactic surveys to study galaxy birth and evolution. By extending Spitzer through 2020, it can continue to make ground-breaking discoveries in those fields, and provide crucial support to the NASA flagship missions JWST and WFIRST, as well as the upcoming TESS mission, and it will complement ground-based observations by LSST and the new large telescopes of the next decade. This scientific program addresses NASA's Science Mission Directive's objectives in astrophysics, which include discovering how the universe works, exploring how it began and evolved, and searching for life on planets around other stars.

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arXiv2017

The DEdicated MONitor of EXotransits and Transients (DEMONEXT): System Overview and Year One Results from a Low-Cost Robotic Telescope for Follow-Up of Exoplanetary Transits and Transients

We report on the design and first year of operations of the DEdicated MONitor of EXotransits and Transients (DEMONEXT). DEMONEXT is a 20 inch (0.5-m) robotic telescope using a PlaneWave CDK20 telescope on a Mathis instruments MI-750/1000 fork mount. DEMONEXT is equipped with a $2048\times2048$ pixel Finger Lakes Instruments (FLI) detector, a 10-position filter wheel with an electronic focuser and $B$, $V$, $R$, $I$, $g'$, $r'$, $i'$, $z'$, and clear filters. DEMONEXT operates in a continuous observing mode and achieves 2-4 mmag raw, unbinned, precision on bright $V<13$ targets with 20-120 second exposures, and 1 mmag precision achieved by binning on 5-6 minute timescales. DEMONEXT maintains sub-pixel ($<0.5$ pixels) target position stability on the CCD over 8 hours in good observing conditions, with degraded performance in poor weather ($<1$ pixel). DEMONEXT achieves 1-10% photometry on single-epoch targets with $V<17$ in 5 minute exposures, with detection thresholds of $V\approx21$. The DEMONEXT automated software has produced 143 planetary candidate transit light curves for the KELT collaboration, and 48 supernovae and transient light curves for the ASAS-SN supernovae group in the first year of operation. DEMONEXT has also observed for a number of ancillary science projects including Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation.

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arXiv2017

Identification of Young Stellar Variables with KELT for K2 I: Campaign 13 Taurus Dippers and Rotators

One of the most well-studied young stellar associations, Taurus-Auriga, will be observed by the extended Kepler mission, K2, in the spring of 2017. K2 Campaign 13 (C13) will be a unique opportunity to study many stars in this young association at high photometric precision and cadence. Using observations from the Kilodegree Extremely Little Telescope (KELT) survey, we identify "dippers", stochastic variables, and periodic variables among K2 C13 target stars. This release of the KELT data (lightcurve data in e-tables) provides the community with long-time baseline observations to assist in the understanding of the more exotic variables in the association. Transient-like phenomena on timescales of months to years are known characteristics in the light curves of young stellar objects, making contextual pre- and post-K2 observations critical to understanding their underlying processes. We are providing a comprehensive set of the KELT light curves for known Taurus-Auriga stars in K2 C13. The combined data sets from K2 and KELT should permit a broad array of investigations related to star formation, stellar variability, and protoplanetary environments.

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arXiv2017

Identification of Young Stellar Variables with KELT for K2 II: The Upper Scorpius Association

High-precision photometry from space-based missions such as K2 and TESS enables detailed studies of young star variability. However, because space-based observing campaigns are often short (e.g., 80 days for K2), complementary long-baseline photometric surveys are critical for obtaining a complete understanding of young star variability, which can change on timescales of minutes to years. We therefore present and analyze light curves of members of the Upper Scorpius association made over 5.5 years by the ground-based Kilodegree Extremely Little Telescope (KELT), which complement the high-precision observations of this region taken by K2 during its Campaigns~2 and 15. We show that KELT data accurately identify the periodic signals found with high-precision K2 photometry, demonstrating the power of ground-based surveys in deriving stellar rotation periods of young stars. We also use KELT data to identify sources exhibiting variability that is likely related to circumstellar material and/or stellar activity cycles; these signatures are often unseen in the short-term K2 data, illustrating the importance of long-term monitoring surveys for studying the full range of young star variability. We provide the KELT light curves as electronic tables in an ongoing effort to establish legacy time-series datasets for young stellar clusters.

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arXiv2017

The Broadband and Spectrally-Resolved H-band Eclipse of KELT-1b and the Role of Surface Gravity in Stratospheric Inversions in Hot Jupiters

We present a high precision H-band emission spectrum of the transiting brown dwarf KELT-1b, which we spectrophotometrically observed during a single secondary eclipse using the LUCI1 multi-object spectrograph on the Large Binocular Telescope. Using a Gaussian-process regression model, we are able to clearly measure the broadband eclipse depth as Delta-H=1418+/-94ppm. We are also able to spectrally-resolve the H-band into five separate wavechannels and measure the eclipse spectrum of KELT-1b at R~50 with an average precision of +/-135ppm. We find that the day side has an average brightness temperature of 3250+/-50K, with significant variation as a function of wavelength. Based on our observations, and previous measurements of KELT-1b's eclipse at other wavelengths, we find that KELT-1b's day side appears identical to an isolated 3200K brown dwarf, and our modeling of the atmospheric emission shows a monotonically decreasing temperature-pressure profile. This is in contrast to hot Jupiters with similar day side brightness temperatures near 3000K, all of which appear to be either isothermal or posses a stratospheric temperature inversion. We hypothesize that the lack of an inversion in KELT-1b is due to its high surface gravity, which we argue could be caused by the increased efficiency of cold-trap processes within its atmosphere.

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arXiv2017

Empirical Bolometric Fluxes and Angular Diameters of 1.6 Million Tycho-2 Stars and Radii of 350,000 Stars with \emph{Gaia} DR1 Parallaxes

We present bolometric fluxes and angular diameters for over 1.6 million stars in the {\it Tycho-2} catalog, determined using previously-determined empirical color-temperature and color-flux relations. We vet these relations via full fits to the full broadband spectral energy distributions for a subset of benchmark stars, and perform quality checks against the large set of stars for which spectroscopically-determined parameters are available from LAMOST, RAVE, and/or APOGEE. We then estimate radii for the 355,502 {\it Tycho-2} stars in our sample whose \emph{Gaia} DR1 parallaxes are precise to $\lesssim$10\%. For the 64,960 of these stars with external spectroscopic information, we achieve median uncertainties on the effective temperatures, bolometric fluxes, angular diameters, and radii of $1.0\%$, $1.4\%$, $2.4\%$, and $7.5\%$, respectively. For the 290,542 remaining stars, we achieve median uncertainties of $0.9\%$, $1.3\%$, $2.2\%$, and $7.5\%$, respectively. These stellar parameters are shown to be reliable for stars with $T_{\rm eff}\lesssim$7000~K. The over half a million bolometric fluxes and angular diameters presented here will serve as an immediate trove of empirical stellar radii with the {\it Gaia\/} second data release, at which point effective temperature uncertainties will dominate the radius uncertainties. Already, dwarf, subgiant, and giant populations are readily identifiable in our purely empirical luminosity-effective temperature (theoretical) Hertzsprung-Russell diagrams.

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arXiv2017

KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603

We report the discovery of KELT-20b, a hot Jupiter transiting a V~7.6 early A star with an orbital period of P~3.47 days. We identified the initial transit signal in KELT-North survey data. Archival and follow-up photometry, the Gaia parallax, radial velocities, Doppler tomography, and adaptive optics imaging were used to confirm the planetary nature of the companion and characterize the system. From global modeling we infer that the host star HD 185603 is a rapidly-rotating (VsinI~120 km/s) A2V star with an effective temperature of $T_{eff}$=8730K, mass of $M_{star}=1.76M_{sun}$, radius of $R_{star}=1.561R_{sun}$, surface gravity of logg=4.292, and age of <600 Myr. The planetary companion has a radius of $1.735^{+0.070}_{-0.075}~R_{J}$, a semimajor axis of $a=0.0542^{+0.0014}_{-0.0021}$AU, and a linear ephemeris of $BJD_{TDB}=2457503.120049 \pm 0.000190 + E(3.4741070\pm0.0000019)$. We place a $3σ$ upper limit of ~3.5 $M_{J}$ on the mass of the planet. The Doppler tomographic measurement indicates that the planetary orbit is well aligned with the projected spin-axis of the star ($λ= 3.4\pm {2.1}$ degrees). The inclination of the star is constrained to be $24.4<I_*<155.6$ degrees, implying a true (three-dimensional) spin-orbit alignment of $1.3<ψ<69.8$ degrees. The planet receives an insolation flux of $\sim 8\times 10^9~{\rm erg~s^{-1}~cm^{-2}}$, implying an equilibrium temperature of of ~ 2250 K, assuming zero albedo and complete heat redistribution. Due to the high stellar $T_{eff}$, the planet also receives an ultraviolet (wavelengths $d\le 91.2$~nm) insolation flux of $\sim 9.1\times 10^4~{\rm erg~s^{-1}~cm^{-2}}$, which may lead to significant ablation of the planetary atmosphere. Together with WASP-33, Kepler-13 A, HAT-P-57, KELT-17, and KELT-9, KELT-20 is the sixth A star host of a transiting giant planet, and the third-brightest host (in V) of a transiting planet.

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arXiv2017

A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host

The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extra-solar planets now known, only four giant planets have been found that transit hot, A-type stars (temperatures of 7300-10,000K), and none are known to transit even hotter B-type stars. WASP-33 is an A-type star with a temperature of ~7430K, which hosts the hottest known transiting planet; the planet is itself as hot as a red dwarf star of type M. The planet displays a large heat differential between its day-side and night-side, and is highly inflated, traits that have been linked to high insolation. However, even at the temperature of WASP-33b's day-side, its atmosphere likely resembles the molecule-dominated atmospheres of other planets, and at the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be significantly ablated over the lifetime of its star. Here we report observations of the bright star HD 195689, which reveal a close-in (orbital period ~1.48 days) transiting giant planet, KELT-9b. At ~10,170K, the host star is at the dividing line between stars of type A and B, and we measure the KELT-9b's day-side temperature to be ~4600K. This is as hot as stars of stellar type K4. The molecules in K stars are entirely dissociated, and thus the primary sources of opacity in the day-side atmosphere of KELT-9b are likely atomic metals. Furthermore, KELT-9b receives ~700 times more extreme ultraviolet radiation (wavelengths shorter than 91.2 nanometers) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.

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arXiv2017

A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass-Radius Relationship for M-dwarfs

We report the discovery of KELT J041621-620046, a moderately bright (J$\sim$10.2) M dwarf eclipsing binary system at a distance of 39$\pm$3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extremely Little Telescope (KELT) survey. The system has a short orbital period of $\sim$1.11 days and consists of components with M$_1$ = $0.447^{-0.047}_{+0.052}\,M_\odot$ and M$_2$ = $0.399^{-0.042}_{+0.046}\,M_\odot$ in nearly circular orbits. The radii of the two stars are R$_1$ = $0.540^{-0.032}_{+0.034}\,R_\odot$ and R$_2$ = $0.453\pm0.017\,R_\odot$. Full system and orbital properties were determined (to $\sim$10% error) by conducting an EBOP global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17-28% and cooler by 4-10% than predicted by standard (non-magnetic) stellar models. Strong H$α$ emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.

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arXiv2017

KELT-18b: Puffy Planet, Hot Host, Probably Perturbed

We report the discovery of KELT-18b, a transiting hot Jupiter in a 2.87d orbit around the bright (V=10.1), hot, F4V star BD+60 1538 (TYC 3865-1173-1). We present follow-up photometry, spectroscopy, and adaptive optics imaging that allow a detailed characterization of the system. Our preferred model fits yield a host stellar temperature of 6670+/-120 K and a mass of 1.524+/-0.069 Msun, situating it as one of only a handful of known transiting planets with hosts that are as hot, massive, and bright. The planet has a mass of 1.18+/-0.11 Mjup, a radius of 1.57+/-0.04 Rjup, and a density of 0.377+/-0.040 g/cm^3, making it one of the most inflated planets known around a hot star. We argue that KELT-18b's high temperature and low surface gravity, which yield an estimated ~600 km atmospheric scale height, combined with its hot, bright host make it an excellent candidate for observations aimed at atmospheric characterization. We also present evidence for a bound stellar companion at a projected separation of ~1100 AU, and speculate that it may have contributed to the strong misalignment we suspect between KELT-18's spin axis and its planet's orbital axis. The inferior conjunction time is 2457542.524998 +/-0.000416 (BJD_TDB) and the orbital period is 2.8717510 +/- 0.0000029 days. We encourage Rossiter-McLaughlin measurements in the near future to confirm the suspected spin-orbit misalignment of this system.

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arXiv2017

Photometric Variability of the Be Star Population

Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, baseline of up to ten years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the Northern and Southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-type. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectral Database (BeSS) allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.

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arXiv2017

Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes

We present empirical measurements of the radii of 116 stars that host transiting planets. These radii are determined using only direct observables-the bolometric flux at Earth, the effective temperature, and the parallax provided by the Gaia first data release-and thus are virtually model independent, extinction being the only free parameter. We also determine each star's mass using our newly determined radius and the stellar density, itself a virtually model independent quantity from previously published transit analyses. These stellar radii and masses are in turn used to redetermine the transiting planet radii and masses, again using only direct observables. The median uncertainties on the stellar radii and masses are ~8% and ~30%, respectively, and the resulting uncertainties on the planet radii and masses are ~9% and ~22%, respectively. These accuracies are generally larger than previously published model-dependent precisions of ~5% and ~6% on the planet radii and masses, respectively, but the newly determined values are purely empirical. We additionally report radii for 242 stars hosting radial-velocity (non-transiting) planets, with median achieved accuracy of ~2%. Using our empirical stellar masses we verify that the majority of putative "retired A stars" in the sample are indeed more massive than ~1.2 Msun. Most importantly, the bolometric fluxes and angular radii reported here for a total of 498 planet host stars-with median accuracies of 1.7% and 1.8%, respectively-serve as a fundamental dataset to permit the re-determination of transiting planet radii and masses with the Gaia second data release to ~3% and ~5% accuracy, better than currently published precisions, and determined in an entirely empirical fashion.

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arXiv2017

KELT-16b: A highly irradiated, ultra-short period hot Jupiter nearing tidal disruption

We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright ($V = 11.7$) star TYC 2688-1839-1. A global analysis of the system shows KELT-16 to be an F7V star with $T_\textrm{eff} = 6236\pm54$ K, $\log{g_\star} = 4.253_{-0.036}^{+0.031}$, [Fe/H] = -0.002$_{-0.085}^{+0.086}$, $M_\star = 1.211_{-0.046}^{+0.043} M_\odot$, and $R_\star = 1.360_{-0.053}^{+0.064} R_\odot$. The planet is a relatively high mass inflated gas giant with $M_\textrm{P} = 2.75_{-0.15}^{+0.16} M_\textrm{J}$, $R_\textrm{P} = 1.415_{-0.067}^{+0.084} R_\textrm{J}$, density $ρ_\textrm{P} = 1.20\pm0.18$ g cm$^{-3}$, surface gravity $\log{g_\textrm{P}} = 3.530_{-0.049}^{+0.042}$, and $T_\textrm{eq} = 2453_{-47}^{+55}$ K. The best-fitting linear ephemeris is $T_\textrm{C} = 2457247.24791\pm0.00019$ BJD$_{tdb}$ and $P = 0.9689951 \pm 0.0000024$ d. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with $P < 1$ day. Its ultra-short period and high irradiation make it a benchmark target for atmospheric studies by HST, Spitzer, and eventually JWST. For example, as a hotter, higher mass analog of WASP-43b, KELT-16b may feature an atmospheric temperature-pressure inversion and day-to-night temperature swing extreme enough for TiO to rain out at the terminator. KELT-16b could also join WASP-43b in extending tests of the observed mass-metallicity relation of the Solar System gas giants to higher masses. KELT-16b currently orbits at a mere $\sim$ 1.7 Roche radii from its host star, and could be tidally disrupted in as little as a few $\times 10^{5}$ years (for a stellar tidal quality factor of $Q_*' = 10^5$). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov oscillations played a role in driving KELT-16b inward to its current precarious orbit.

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arXiv2017

The Mysterious Dimmings of the T Tauri Star V1334 Tau

We present the discovery of two extended $\sim$0.12 mag dimming events of the weak-lined T-Tauri star V1334. The start of the first event was missed but came to an end in late 2003, and the second began in February 2009, and continues as of November 2016. Since the egress of the current event has not yet been observed, it suggests a period of $>$13 years if this event is periodic. Spectroscopic observations suggest the presence of a small inner disk, although the spectral energy distribution shows no infrared excess. We explore the possibility that the dimming events are caused by an orbiting body (e.g. a disk warp or dust trap), enhanced disk winds, hydrodynamical fluctuations of the inner disk, or a significant increase in the magnetic field flux at the surface of the star. We also find a $\sim$0.32 day periodic photometric signal that persists throughout the 2009 dimming which appears to not be due to ellipsoidal variations from a close stellar companion. High precision photometric observations of V1334 Tau during K2 campaign 13, combined with simultaneous photometric and spectroscopic observations from the ground, will provide crucial information about the photometric variability and its origin.

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arXiv2016

iLocater: A Diffraction-limited Doppler Spectrometer for the Large Binocular Telescope

We are developing a stable and precise spectrograph for the Large Binocular Telescope (LBT) named "iLocater." The instrument comprises three principal components: a cross-dispersed echelle spectrograph that operates in the YJ-bands (0.97-1.30 microns), a fiber-injection acquisition camera system, and a wavelength calibration unit. iLocater will deliver high spectral resolution (R~150,000-240,000) measurements that permit novel studies of stellar and substellar objects in the solar neighborhood including extrasolar planets. Unlike previous planet-finding instruments, which are seeing-limited, iLocater operates at the diffraction limit and uses single mode fibers to eliminate the effects of modal noise entirely. By receiving starlight from two 8.4m diameter telescopes that each use "extreme" adaptive optics (AO), iLocater shows promise to overcome the limitations that prevent existing instruments from generating sub-meter-per-second radial velocity (RV) precision. Although optimized for the characterization of low-mass planets using the Doppler technique, iLocater will also advance areas of research that involve crowded fields, line-blanketing, and weak absorption lines.

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