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783 results on '"Everett, Mark E."'

152. Groundwater erosion of coastal gullies along the Canterbury coast (New Zealand) : a rapid and episodic process controlled by rainfall intensity and substrate variability

Author

Micallef, Aaron, Marchis, Remus, Saadatkhah, Nader, Pondthai, Potpreecha, Everett, Mark E., Avram, Anca, Timar-Gabor, Alida, Cohen, Denis, Preca Trapani, Rachel, Weymer, Bradley A., and Wernette, Phillipe

Subjects
Geotechnical engineering, Environmental management, Groundwater -- New Zealand, Hydrogeology, Hydrology
Abstract

Gully formation has been associated to groundwater seepage in unconsolidated sand- to gravel-sized sediments. Our understanding of gully evolution by groundwater seepage mostly relies on experiments and numerical simulations, and these rarely take into consideration contrasts in lithology and permeability. In addition, process-based observations and detailed instrumental analyses are rare. As a result, we have a poor understanding of the temporal scale of gully formation by groundwater seepage and the influence of geological heterogeneity on their formation. This is particularly the case for coastal gullies, where the role of groundwater in their formation and evolution has rarely been assessed. We address these knowledge gaps along the Canterbury coast of the South Island (New Zealand) by integrating field observations, luminescence dating, multi-temporal unoccupied aerial vehicle and satellite data, time domain electromagnetic data and slope stability modelling. We show that gully formation is a key process shaping the sandy gravel cliffs of the Canterbury coastline. It is an episodic process associated to groundwater flow that occurs once every 227 d on average, when rainfall intensities exceed 40mmd􀀀1. The majority of the gullies in a study area southeast (SE) of Ashburton have undergone erosion, predominantly by elongation, during the last 11 years, with the most recent episode occurring 3 years ago. Gullies longer than 200m are relict features formed by higher groundwater flow and surface erosion >2 ka ago. Gullies can form at rates of up to 30md􀀀1 via two processes, namely the formation of alcoves and tunnels by groundwater seepage, followed by retrogressive slope failure due to undermining and a decrease in shear strength driven by excess pore pressure development. The location of gullies is determined by the occurrence of hydraulically conductive zones, such as relict braided river channels and possibly tunnels, and of sand lenses exposed across sandy gravel cliffs.We also show that the gully planform shape is generally geometrically similar at consecutive stages of evolution. These outcomes will facilitate the reconstruction and prediction of a prevalent erosive process and overlooked geohazard along the Canterbury coastline., peer-reviewed

Published
2021

153. An Ultra-short Period Rocky Super-Earth with a Secondary Eclipse and a Neptune-like Companion around K2-141

Author

Massachusetts Institute of Technology. Department of Physics, Malavolta, Luca, Mayo, Andrew W., Louden, Tom, Rajpaul, Vinesh M., Bonomo, Aldo S., Crossfield, Ian Jm, Buchhave, Lars A., Kreidberg, Laura, Kristiansen, Martti H., Lopez-Morales, Mercedes, Mortier, Annelies, Vanderburg, Andrew, Coffinet, Adrien, Ehrenreich, David, Lovis, Christophe, Bouchy, Francois, Charbonneau, David, Ciardi, David R., Cameron, Andrew Collier, Cosentino, Rosario, Damasso, Mario, Dressing, Courtney D., Dumusque, Xavier, Everett, Mark E., Figueira, Pedro, Fiorenzano, Aldo F. M., Gonzales, Erica J., Haywood, Raphaëlle D., Harutyunyan, Avet, Hirsch, Lea, Howell, Steve B., Johnson, John Asher, Latham, David W., Lopez, Eric, Mayor, Michel, Micela, Giusi, Molinari, Emilio, Nascimbeni, Valerio, Pepe, Francesco, Phillips, David F., Piotto, Giampaolo, Rice, Ken, Sasselov, Dimitar, Ségransan, Damien, Sozzetti, Alessandro, Udry, Stéphane, Watson, Chris, Massachusetts Institute of Technology. Department of Physics, Malavolta, Luca, Mayo, Andrew W., Louden, Tom, Rajpaul, Vinesh M., Bonomo, Aldo S., Crossfield, Ian Jm, Buchhave, Lars A., Kreidberg, Laura, Kristiansen, Martti H., Lopez-Morales, Mercedes, Mortier, Annelies, Vanderburg, Andrew, Coffinet, Adrien, Ehrenreich, David, Lovis, Christophe, Bouchy, Francois, Charbonneau, David, Ciardi, David R., Cameron, Andrew Collier, Cosentino, Rosario, Damasso, Mario, Dressing, Courtney D., Dumusque, Xavier, Everett, Mark E., Figueira, Pedro, Fiorenzano, Aldo F. M., Gonzales, Erica J., Haywood, Raphaëlle D., Harutyunyan, Avet, Hirsch, Lea, Howell, Steve B., Johnson, John Asher, Latham, David W., Lopez, Eric, Mayor, Michel, Micela, Giusi, Molinari, Emilio, Nascimbeni, Valerio, Pepe, Francesco, Phillips, David F., Piotto, Giampaolo, Rice, Ken, Sasselov, Dimitar, Ségransan, Damien, Sozzetti, Alessandro, Udry, Stéphane, and Watson, Chris

Abstract

Ultra-short period (USP) planets are a class of low-mass planets with periods shorter than one day. Their origin is still unknown, with photo-evaporation of mini-Neptunes and in situ formation being the most credited hypotheses. Formation scenarios differ radically in the predicted composition of USP planets, and it is therefore extremely important to increase the still limited sample of USP planets with precise and accurate mass and density measurements. We report here the characterization of a USP planet with a period of 0.28 days around K2-141 (EPIC 246393474), and the validation of an outer planet with a period of 7.7 days in a grazing transit configuration. We derived the radii of the planets from the K2 light curve and used high-precision radial velocities gathered with the HARPS-N spectrograph for mass measurements. For K2-141b, we thus inferred a radius of 1.51 ±0.05 R and a mass of 5.08 ±0.41 M, consistent with a rocky composition and lack of a thick atmosphere. K2-141c is likely a Neptune-like planet, although due to the grazing transits and the non-detection in the RV data set, we were not able to put a strong constraint on its density. We also report the detection of secondary eclipses and phase curve variations for K2-141b. The phase variation can be modeled either by a planet with a geometric albedo of 0.30 ±0.06 in the Kepler bandpass, or by thermal emission from the surface of the planet at ∼3000 K. Only follow-up observations at longer wavelengths will allow us to distinguish between these two scenarios., United States. National Aeronautics and Space Administration (Grant NNX15AC90G), United States. National Aeronautics and Space Administration (Grant NNX17AB59G)

Published
2021

154. HAT-P-68b: A Transiting Hot Jupiter Around a K5 Dwarf Star

Author

Lindor, Bethlee M., Hartman, Joel D., Bakos, Gáspár Á., Bhatti, Waqas, Csubry, Zoltan, Penev, Kaloyan, Bieryla, Allyson, Latham, David W., Torres, Guillermo, Buchhave, Lars A., Kovács, Géza, de Val-Borro, Miguel, Howard, Andrew W., Isaacson, Howard, Fulton, Benjamin J., Boisse, Isabelle, Santerne, Alexandre, Hébrard, Guillaume, Kovács, Támás, Huang, Chelsea X., Dembicky, Jack, Falco, Emilio, Everett, Mark E., Horch, Elliott P., Lázár, József, Papp, István, Sári, Pál, Lindor, Bethlee M., Hartman, Joel D., Bakos, Gáspár Á., Bhatti, Waqas, Csubry, Zoltan, Penev, Kaloyan, Bieryla, Allyson, Latham, David W., Torres, Guillermo, Buchhave, Lars A., Kovács, Géza, de Val-Borro, Miguel, Howard, Andrew W., Isaacson, Howard, Fulton, Benjamin J., Boisse, Isabelle, Santerne, Alexandre, Hébrard, Guillaume, Kovács, Támás, Huang, Chelsea X., Dembicky, Jack, Falco, Emilio, Everett, Mark E., Horch, Elliott P., Lázár, József, Papp, István, and Sári, Pál

Abstract

We report the discovery by the ground-based Hungarian-made Automated Telescope Network (HATNet) survey of the transiting exoplanet HAT-P-68b, which has a mass of 0.724 ± 0.043 M J, and radius of 1.072 ± 0.012 R J. The planet is in a circular P = 2.2984 day orbit around a moderately bright V = 13.937 ± 0.030 magnitude K-dwarf star of mass M ⊙, and radius 0.6726 ± 0.0069 R ⊙. The planetary nature of this system is confirmed through follow-up transit photometry obtained with the Fred L. Whipple Observatory (FLWO) 1.2 m telescope, high-precision radial velocities measured using Keck I/High Resolution Echelle Spectrometer (HIRES), FLWO 1.5 m/Tillinghast Reflector Echelle Spectrograph (TRES), and Observatoire de Haute-Provence (OHP) 1.9 m/Sophie, and high-spatial-resolution speckle imaging from WIYN 3.5 m/DSSI. HAT-P-68 is at an ecliptic latitude of +3° and outside the field of view of both the NASA Transiting Exoplanet Survey Satellite primary mission and the K2 mission. The large transit depth of 0.036 mag (r band) makes HAT-P-68b a promising target for atmospheric characterization via transmission spectroscopy.

Published
2021

156. The NEID precision radial velocity spectrometer: Commissioning of the Port Adapter

Author

Logsdon, Sarah E., Wolf, Marsha J., Everett, Mark E., Gong, Qian, Golub, Eli, Valdenebro, Jesus, Hunting, Emily, Jaehnig, Kurt P., Klusmeyer, Jessica, Li, Dan, Liang, Ming, Liu, Wilson, McBride, William, McElwain, Michael W., Percival, Jeffrey W., Rajagopal, Jayadev, Ridgway, Susan, Schweiker, Heidi, Smith, Michael P., Timmermann, Erik, Santoro, Fernando, Schwab, Christian, Bender, Chad F., Blake, Cullen, Halverson, Samuel P., Hearty, Fred, Kanodia, Shubham, Mahadevan, Suvrath, Monson, Andrew J., Ninan, Joe P., Ramsey, Lawrence W., Robertson, Paul, Roy, Arpita, Terrien, Ryan C., Wright, Jason T., Evans, Christopher J., Bryant, Julia J., and Motohara, Kentaro

Abstract

In October 2019, the NEID instrument (PI Suvrath Mahadevan, PSU) was delivered to the WIYN 3.5 m Telescope at Kitt Peak National Observatory. Commissioning began shortly after delivery, but was paused due to a COVID-19 imposed observatory shutdown in March 2020. The observatory has recently reopened and NEID commissioning has resumed. NEID is an optical (380-930 nm), fiber-fed, precision Doppler radial velocity system developed as part of the NN-EXPLORE partnership. While the spectrometer and calibration system are maintained in a highly controlled environment on the basement level of the WIYN, the NEID Port Adapter mounts directly to a bent-Cassegrain port on the telescope and is responsible for precisely and stably placing target light on the science fibers. Here we present a brief overview of the as-built Port Adapter and its sub-components. We then discuss preliminary on-sky performance compared to requirements as well as next steps as we complete commissioning.

Published
2020

161. Speckle Imaging Characterization of Radial Velocity Exoplanet Systems

Author

Dalba, Paul A., primary, Kane, Stephen R., additional, Howell, Steve B., additional, Horch, Elliott P., additional, Li, Zhexing, additional, Hirsch, Lea A., additional, Burt, Jennifer, additional, Brandt, Timothy D., additional, Močnik, Teo, additional, Henry, Gregory W., additional, Everett, Mark E., additional, Rosenthal, Lee J., additional, and Howard, Andrew W., additional

Published
2021
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162. The NEID precision radial velocity spectrometer: Commissioning of the Port Adapter

Author

Evans, Christopher J., Bryant, Julia J., Motohara, Kentaro, Logsdon, Sarah E., Wolf, Marsha J., Everett, Mark E., Gong, Qian, Golub, Eli, Valdenebro, Jesus, Hunting, Emily, Jaehnig, Kurt P., Klusmeyer, Jessica, Li, Dan, Liang, Ming, Liu, Wilson, McBride, William, McElwain, Michael W., Percival, Jeffrey W., Rajagopal, Jayadev, Ridgway, Susan, Schweiker, Heidi, Smith, Michael P., Timmermann, Erik, Santoro, Fernando, Schwab, Christian, Bender, Chad F., Blake, Cullen, Halverson, Samuel P., Hearty, Fred, Kanodia, Shubham, Mahadevan, Suvrath, Monson, Andrew J., Ninan, Joe P., Ramsey, Lawrence W., Robertson, Paul, Roy, Arpita, Terrien, Ryan C., Wright, Jason T., Evans, Christopher J., Bryant, Julia J., Motohara, Kentaro, Logsdon, Sarah E., Wolf, Marsha J., Everett, Mark E., Gong, Qian, Golub, Eli, Valdenebro, Jesus, Hunting, Emily, Jaehnig, Kurt P., Klusmeyer, Jessica, Li, Dan, Liang, Ming, Liu, Wilson, McBride, William, McElwain, Michael W., Percival, Jeffrey W., Rajagopal, Jayadev, Ridgway, Susan, Schweiker, Heidi, Smith, Michael P., Timmermann, Erik, Santoro, Fernando, Schwab, Christian, Bender, Chad F., Blake, Cullen, Halverson, Samuel P., Hearty, Fred, Kanodia, Shubham, Mahadevan, Suvrath, Monson, Andrew J., Ninan, Joe P., Ramsey, Lawrence W., Robertson, Paul, Roy, Arpita, Terrien, Ryan C., and Wright, Jason T.

Abstract

In October 2019, the NEID instrument (PI Suvrath Mahadevan, PSU) was delivered to the WIYN 3.5 m Telescope at Kitt Peak National Observatory. Commissioning began shortly after delivery, but was paused due to a COVID-19 imposed observatory shutdown in March 2020. The observatory has recently reopened and NEID commissioning has resumed. NEID is an optical (380-930 nm), fiber-fed, precision Doppler radial velocity system developed as part of the NN-EXPLORE partnership. While the spectrometer and calibration system are maintained in a highly controlled environment on the basement level of the WIYN, the NEID Port Adapter mounts directly to a bent-Cassegrain port on the telescope and is responsible for precisely and stably placing target light on the science fibers. Here we present a brief overview of the as-built Port Adapter and its sub-components. We then discuss preliminary on-sky performance compared to requirements as well as next steps as we complete commissioning.

Published
2020

163. Multi-Layered High Permeability Conduits Connecting Onshore and Offshore Coastal Aquifers

Author

Weymer, Bradley A., Wernette, Phillipe A., Everett, Mark E., Pondthai, Potpreecha, Jegen, Marion, Micallef, Aaron, Weymer, Bradley A., Wernette, Phillipe A., Everett, Mark E., Pondthai, Potpreecha, Jegen, Marion, and Micallef, Aaron

Abstract

Groundwater resources in coastal regions are facing enormous pressure caused by population growth and climate change. Few studies have investigated whether offshore freshened groundwater systems are connected with terrestrial aquifers recharged by meteoric water, or paleo-groundwater systems that are no longer associated with terrestrial aquifers. Distinguishing between the two has important implications for potential extraction to alleviate water stress for many coastal communities, yet very little is known about these connections, mainly because it is difficult to acquire continuous subsurface information across the coastal transition zone. This study presents a first attempt to bridge this gap by combining three complementary near-surface electromagnetic methods to image groundwater pathways within braided alluvial gravels along the Canterbury coast, South Island, New Zealand. We show that collocated electromagnetic induction, ground penetrating radar, and transient electromagnetic measurements, which are sensitive to electrical contrasts between fresh (low conductivity) and saline (high conductivity) groundwater, adequately characterize hydrogeologic variations beneath a mixed sand gravel beach in close proximity to the Ashburton River mouth. The combined measurements – providing information at three different depths of investigation and resolution – show several conductive zones that are correlated with spatial variations in subsurface hydrogeology. We interpret the conductive zones as high permeability conduits corresponding to lenses of well-sorted gravels and secondary channel fill deposits within the braided river deposit architecture. The geophysical surveys provide the basis for a discharge model that fits our observations, namely that there is evidence of a multilayered system focusing groundwater flow through stacked high permeability gravel layers analogous to a subterranean river network. Coincident geophysical surveys in a region further offshore ind

Published
2020
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164. 3D Characterization of a Coastal Freshwater Aquifer in SE Malta (Mediterranean Sea) by Time-Domain Electromagnetics

Author

Pondthai, Potpreecha, Everett, Mark E., Micallef, Aaron, Weymer, Bradley A., Faghih, Zahra, Haroon, Amir, Jegen, Marion, Pondthai, Potpreecha, Everett, Mark E., Micallef, Aaron, Weymer, Bradley A., Faghih, Zahra, Haroon, Amir, and Jegen, Marion

Abstract

Electromagnetic (EM) geophysical methods are well equipped to distinguish electrical resistivity contrasts between freshwater-saturated and seawater-saturated formations. Beneath the semi-arid, rapidly urbanizing island of Malta, offshore groundwater is an important potential resource but it is not known whether the regional mean sea-level aquifer (MSLA) extends offshore. To address this uncertainty, land-based alongshore and across-shore time-domain electromagnetic (TDEM) responses were acquired with the G-TEM instrument (Geonics Ltd., Mississauga, ON, Canada) and used to map the onshore structure of the aquifer. 1-D inversion results suggest that the onshore freshwater aquifer resides at 4–24 m depth, underlain by seawater-saturated formations. The freshwater aquifer thickens with distance from the coastline. We present 2D and 3D electromagnetic forward modeling based on finite-element (FE) analysis to further constrain the subsurface geometry of the onshore freshwater body. We interpret the high resistivity zones that as brackish water-saturated bodies are associated with the mean sea-level aquifer. Generally, time-domain electromagnetic (TDEM) results provide valuable onshore hydrogeological information, which can be augmented with marine and coastal transition-zone measurements to assess potential hydraulic continuity of terrestrial aquifers extending offshore.

Published
2020
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166. Mutual induction and the effect of host conductivity on the EM induction response of buried plate targets using 3-D finite-element analysis

Author

Stalnaker, Jack L., Everett, Mark E., Benavides, Alfonso, and Pierce, Carl J., Jr.

Subjects
Eddy currents (Electric) -- Analysis, Induction, Electromagnetic -- Research, Finite element method -- Usage, Business, Earth sciences, Electronics and electrical industries
Abstract

A finite-element analysis of electromagnetic induction (EMI) in the presence of multiple buried metal targets is undertaken for the purpose of unexploded ordnance (UXO) detection and discrimination. The effects of mutual coupling between metal targets and the host conductivity are shown to be important. At high frequencies, mutual coupling is strong, and effects of host conductivity are relatively minor. At lower frequencies near the resistive limit, EMI responses are very small, but the effect of host conductivity becomes important. This is due to the galvanic current flow in the host medium that dissipates charge accumulations on the host/target interfaces. Qualitative analysis of induced current patterns in metal targets demonstrates that mutual coupling is strongly affected by target orientation and skin depth. Rigorous forward modeling of EMI responses is essential to understanding UXO sensor signatures so that discrimination between live UXO items and harmless fragments and clutter may become possible. Index Terms--Eddy currents, electromagnetic induction (EMI), finite-element methods (FEMs), geophysics, mutual coupling.

Published
2006

167. HAT-P-68b: A Transiting Hot Jupiter around a K5 Dwarf Star

Author

Lindor, Bethlee M., primary, Hartman, Joel D., additional, Bakos, Gáspár Á., additional, Bhatti, Waqas, additional, Csubry, Zoltan, additional, Penev, Kaloyan, additional, Bieryla, Allyson, additional, Latham, David W., additional, Torres, Guillermo, additional, Buchhave, Lars A., additional, Val-Borro, Miguel de, additional, Howard, Andrew W., additional, Isaacson, Howard, additional, Fulton, Benjamin J., additional, Boisse, Isabelle, additional, Santerne, Alexandre, additional, Hébrard, Guillaume, additional, Kovács, Támás, additional, Huang, Chelsea X., additional, Dembicky, Jack, additional, Falco, Emilio, additional, Everett, Mark E., additional, Horch, Elliott P., additional, Lázár, József, additional, Papp, István, additional, and Sári, Pál, additional

Published
2021
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170. Planetary candidates transiting cool dwarf stars from campaigns 12 to 15 of K2

Author

Castro González, A, primary, Díez Alonso, E, additional, Menéndez Blanco, J, additional, Livingston, John H, additional, de Leon, Jerome P, additional, Suárez Gómez, S L, additional, González Gutiérrez, C, additional, García Riesgo, F, additional, Bonavera, L, additional, Iglesias Rodríguez, F J, additional, Muñiz, R, additional, Everett, Mark E, additional, Scott, N J, additional, Howell, Steve B, additional, Ciardi, David R, additional, Gonzales, Erica J, additional, Schlieder, Joshua E, additional, and de Cos Juez, F J, additional

Published
2020
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174. A Warm Jupiter Transiting an M Dwarf: A TESS Single-transit Event Confirmed with the Habitable-zone Planet Finder

Author

Cañas, Caleb I., primary, Stefansson, Gudmundur, additional, Kanodia, Shubham, additional, Mahadevan, Suvrath, additional, Cochran, William D., additional, Endl, Michael, additional, Robertson, Paul, additional, Bender, Chad F., additional, Ninan, Joe P., additional, Beard, Corey, additional, Lubin, Jack, additional, Gupta, Arvind F., additional, Everett, Mark E., additional, Monson, Andrew, additional, Wilson, Robert F., additional, Lewis, Hannah M., additional, Brewer, Mary, additional, Majewski, Steven R., additional, Hebb, Leslie, additional, Dawson, Rebekah I., additional, Diddams, Scott A., additional, Ford, Eric B., additional, Fredrick, Connor, additional, Halverson, Samuel, additional, Hearty, Fred, additional, Lin, Andrea S. J., additional, Metcalf, Andrew J., additional, Rajagopal, Jayadev, additional, Ramsey, Lawrence W., additional, Roy, Arpita, additional, Schwab, Christian, additional, Terrien, Ryan C., additional, and Wright, Jason T., additional

Published
2020
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175. KELT-25 b and KELT-26 b: A Hot Jupiter and a Substellar Companion Transiting Young A Stars Observed by TESS*

Author

Martínez, Romy Rodríguez, primary, Gaudi, B. Scott, additional, Rodriguez, Joseph E., additional, Zhou, George, additional, Labadie-Bartz, Jonathan, additional, Quinn, Samuel N., additional, Penev, Kaloyan, additional, Tan, Thiam-Guan, additional, Latham, David W., additional, Paredes, Leonardo A., additional, Kielkopf, John F., additional, Addison, Brett, additional, Wright, Duncan J., additional, Teske, Johanna, additional, Howell, Steve B., additional, Ciardi, David, additional, Ziegler, Carl, additional, Stassun, Keivan G., additional, Johnson, Marshall C., additional, Eastman, Jason D., additional, Siverd, Robert J., additional, Beatty, Thomas G., additional, Bouma, Luke, additional, Bedding, Timothy, additional, Pepper, Joshua, additional, Winn, Joshua, additional, Lund, Michael B., additional, Villanueva, Steven, additional, Stevens, Daniel J., additional, Jensen, Eric L. N., additional, Kilby, Coleman, additional, Crane, Jeffrey D., additional, Tokovinin, Andrei, additional, Everett, Mark E., additional, Tinney, C. G., additional, Fausnaugh, Michael, additional, Cohen, David H., additional, Bayliss, Daniel, additional, Bieryla, Allyson, additional, Cargile, Phillip A., additional, Collins, Karen A., additional, Conti, Dennis M., additional, Colón, Knicole D., additional, Curtis, Ivan A., additional, Depoy, D. L., additional, Evans, Phil, additional, Feliz, Dax L., additional, Gregorio, Joao, additional, Rothenberg, Jason, additional, James, David J., additional, Joner, Michael D., additional, Kuhn, Rudolf B., additional, Manner, Mark, additional, Khakpash, Somayeh, additional, Marshall, Jennifer L., additional, McLeod, Kim K., additional, Penny, Matthew T., additional, Reed, Phillip A., additional, Relles, Howard M., additional, Stephens, Denise C., additional, Stockdale, Chris, additional, Trueblood, Mark, additional, Trueblood, Pat, additional, Yao, Xinyu, additional, Zambelli, Roberto, additional, Vanderspek, Roland, additional, Seager, Sara, additional, Jenkins, Jon M., additional, Henry, Todd J., additional, James, Hodari-Sadiki, additional, Jao, Wei-Chun, additional, Wang, Sharon Xuesong, additional, Butler, Paul, additional, Thompson, Ian, additional, Shectman, Stephen, additional, Wittenmyer, Robert, additional, Bowler, Brendan P., additional, Horner, Jonathan, additional, Kane, Stephen R., additional, Mengel, Matthew W., additional, Morton, Timothy D., additional, Okumura, Jack, additional, Plavchan, Peter, additional, Zhang, Hui, additional, Scott, Nicholas J., additional, Matson, Rachel A., additional, Mann, Andrew W., additional, Dragomir, Diana, additional, Günther, Max, additional, Ting, Eric B., additional, Glidden, Ana, additional, and Quintana, Elisa V., additional

Published
2020
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176. The First Habitable-zone Earth-sized Planet from TESS. I. Validation of the TOI-700 System

Author

Gilbert, Emily A., primary, Barclay, Thomas, additional, Schlieder, Joshua E., additional, Quintana, Elisa V., additional, Hord, Benjamin J., additional, Kostov, Veselin B., additional, Lopez, Eric D., additional, Rowe, Jason F., additional, Hoffman, Kelsey, additional, Walkowicz, Lucianne M., additional, Silverstein, Michele L., additional, Rodriguez, Joseph E., additional, Vanderburg, Andrew, additional, Suissa, Gabrielle, additional, Airapetian, Vladimir S., additional, Clement, Matthew S., additional, Raymond, Sean N., additional, Mann, Andrew W., additional, Kruse, Ethan, additional, Lissauer, Jack J., additional, Colón, Knicole D., additional, Kopparapu, Ravi kumar, additional, Kreidberg, Laura, additional, Zieba, Sebastian, additional, Collins, Karen A., additional, Quinn, Samuel N., additional, Howell, Steve B., additional, Ziegler, Carl, additional, Vrijmoet, Eliot Halley, additional, Adams, Fred C., additional, Arney, Giada N., additional, Boyd, Patricia T., additional, Brande, Jonathan, additional, Burke, Christopher J., additional, Cacciapuoti, Luca, additional, Chance, Quadry, additional, Christiansen, Jessie L., additional, Covone, Giovanni, additional, Daylan, Tansu, additional, Dineen, Danielle, additional, Dressing, Courtney D., additional, Essack, Zahra, additional, Fauchez, Thomas J., additional, Galgano, Brianna, additional, Howe, Alex R., additional, Kaltenegger, Lisa, additional, Kane, Stephen R., additional, Lam, Christopher, additional, Lee, Eve J., additional, Lewis, Nikole K., additional, Logsdon, Sarah E., additional, Mandell, Avi M., additional, Monsue, Teresa, additional, Mullally, Fergal, additional, Mullally, Susan E., additional, Paudel, Rishi R., additional, Pidhorodetska, Daria, additional, Plavchan, Peter, additional, Reyes, Naylynn Tañón, additional, Rinehart, Stephen A., additional, Rojas-Ayala, Bárbara, additional, Smith, Jeffrey C., additional, Stassun, Keivan G., additional, Tenenbaum, Peter, additional, Vega, Laura D., additional, Villanueva, Geronimo L., additional, Wolf, Eric T., additional, Youngblood, Allison, additional, Ricker, George R., additional, Vanderspek, Roland K., additional, Latham, David W., additional, Seager, Sara, additional, Winn, Joshua N., additional, Jenkins, Jon M., additional, Bakos, Gáspár Å., additional, Briceño, César, additional, Ciardi, David R., additional, Cloutier, Ryan, additional, Conti, Dennis M., additional, Couperus, Andrew, additional, Di Sora, Mario, additional, Eisner, Nora L., additional, Everett, Mark E., additional, Gan, Tianjun, additional, Hartman, Joel D., additional, Henry, Todd, additional, Isopi, Giovanni, additional, Jao, Wei-Chun, additional, Jensen, Eric L. N., additional, Law, Nicholas, additional, Mallia, Franco, additional, Matson, Rachel A., additional, Shappee, Benjamin J., additional, Le Wood, Mackennae, additional, and Winters, Jennifer G., additional

Published
2020
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177. Box canyon erosion along the Canterbury coast (New Zealand): A rapid and episodic process controlled by rainfall intensity and substrate variability

Author

Micallef, Aaron, primary, Marchis, Remus, additional, Saadatkhah, Nader, additional, Clavera-Gispert, Roger, additional, Pondthai, Potpreecha, additional, Everett, Mark E., additional, Avram, Anca, additional, Timar-Gabor, Alida, additional, Cohen, Denis, additional, Preca Trapani, Rachel, additional, and Weymer, Bradley A., additional

Published
2020
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178. Supplementary material to "Box canyon erosion along the Canterbury coast (New Zealand): A rapid and episodic process controlled by rainfall intensity and substrate variability"

Author

Micallef, Aaron, primary, Marchis, Remus, additional, Saadatkhah, Nader, additional, Clavera-Gispert, Roger, additional, Pondthai, Potpreecha, additional, Everett, Mark E., additional, Avram, Anca, additional, Timar-Gabor, Alida, additional, Cohen, Denis, additional, Preca Trapani, Rachel, additional, and Weymer, Bradley A., additional

Published
2020
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180. Orbital Refinement and Stellar Properties for the HD 9446, HD 43691, and HD 179079 Planetary Systems

Author

Hill, Michelle L., primary, Močnik, Teo, additional, Kane, Stephen R., additional, Henry, Gregory W., additional, Pepper, Joshua, additional, Hinkel, Natalie R., additional, Dalba, Paul A., additional, Fulton, Benjamin J., additional, Stassun, Keivan G., additional, Rosenthal, Lee J., additional, Howard, Andrew W., additional, Howell, Steve B., additional, Everett, Mark E., additional, Boyajian, Tabetha S., additional, Fischer, Debra A., additional, Rodriguez, Joseph E., additional, Beatty, Thomas G., additional, and James, David J., additional

Published
2020
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182. Kepler Planet-Detection Mission: Introduction and First Results

Author

Borucki, William J., Koch, David, Basri, Gibor, Batalha, Natalie, Brown, Timothy, Caldwell, Douglas, Caldwell, John, Christensen-Dalsgaard, Jørgen, Cochran, William D., DeVore, Edna, Dunham, Edward W., Dupree, Andrea K., Gautier, Thomas N., III, Geary, John C., Gilliland, Ronald, Gould, Alan, Howell, Steve B., Jenkins, Jon M., Kondo, Yoji, Latham, David W., Marcy, Geoffrey W., Meibom, Søren, Kjeldsen, Hans, Lissauer, Jack J., Monet, David G., Morrison, David, Sasselov, Dimitar, Tarter, Jill, Boss, Alan, Brownlee, Don, Owen, Toby, Buzasi, Derek, Charbonneau, David, Doyle, Laurance, Fortney, Jonathan, Ford, Eric B., Holman, Matthew J., Seager, Sara, Steffen, Jason H., Welsh, William F., Rowe, Jason, Anderson, Howard, Buchhave, Lars, Ciardi, David, Walkowicz, Lucianne, Sherry, William, Horch, Elliott, Isaacson, Howard, Everett, Mark E., Fischer, Debra, Torres, Guillermo, Johnson, John Asher, Endl, Michael, MacQueen, Phillip, Bryson, Stephen T., Dotson, Jessie, Haas, Michael, Kolodziejczak, Jeffrey, Van Cleve, Jeffrey, Chandrasekaran, Hema, Twicken, Joseph D., Quintana, Elisa V., Clarke, Bruce D., Allen, Christopher, Li, Jie, Wu, Haley, Tenenbaum, Peter, Verner, Ekaterina, Bruhweiler, Frederick, Barnes, Jason, and Prsa, Andrej

Published
2010
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184. An Ultra-short Period Rocky Super-Earth with a Secondary Eclipse and a Neptune-like Companion around K2-141

Author

Massachusetts Institute of Technology. Department of Physics, Malavolta, Luca, Mayo, Andrew W., Louden, Tom, Rajpaul, Vinesh M., Bonomo, Aldo S., Crossfield, Ian Jm, Buchhave, Lars A., Kreidberg, Laura, Kristiansen, Martti H., Lopez-Morales, Mercedes, Mortier, Annelies, Vanderburg, Andrew, Coffinet, Adrien, Ehrenreich, David, Lovis, Christophe, Bouchy, Francois, Charbonneau, David, Ciardi, David R., Cameron, Andrew Collier, Cosentino, Rosario, Damasso, Mario, Dressing, Courtney D., Dumusque, Xavier, Everett, Mark E., Figueira, Pedro, Fiorenzano, Aldo F. M., Gonzales, Erica J., Haywood, Raphaëlle D., Harutyunyan, Avet, Hirsch, Lea, Howell, Steve B., Johnson, John Asher, Latham, David W., Lopez, Eric, Mayor, Michel, Micela, Giusi, Molinari, Emilio, Nascimbeni, Valerio, Pepe, Francesco, Phillips, David F., Piotto, Giampaolo, Rice, Ken, Sasselov, Dimitar, Ségransan, Damien, Sozzetti, Alessandro, Udry, Stéphane, Watson, Chris, Massachusetts Institute of Technology. Department of Physics, Malavolta, Luca, Mayo, Andrew W., Louden, Tom, Rajpaul, Vinesh M., Bonomo, Aldo S., Crossfield, Ian Jm, Buchhave, Lars A., Kreidberg, Laura, Kristiansen, Martti H., Lopez-Morales, Mercedes, Mortier, Annelies, Vanderburg, Andrew, Coffinet, Adrien, Ehrenreich, David, Lovis, Christophe, Bouchy, Francois, Charbonneau, David, Ciardi, David R., Cameron, Andrew Collier, Cosentino, Rosario, Damasso, Mario, Dressing, Courtney D., Dumusque, Xavier, Everett, Mark E., Figueira, Pedro, Fiorenzano, Aldo F. M., Gonzales, Erica J., Haywood, Raphaëlle D., Harutyunyan, Avet, Hirsch, Lea, Howell, Steve B., Johnson, John Asher, Latham, David W., Lopez, Eric, Mayor, Michel, Micela, Giusi, Molinari, Emilio, Nascimbeni, Valerio, Pepe, Francesco, Phillips, David F., Piotto, Giampaolo, Rice, Ken, Sasselov, Dimitar, Ségransan, Damien, Sozzetti, Alessandro, Udry, Stéphane, and Watson, Chris

Abstract

Ultra-short period (USP) planets are a class of low-mass planets with periods shorter than one day. Their origin is still unknown, with photo-evaporation of mini-Neptunes and in situ formation being the most credited hypotheses. Formation scenarios differ radically in the predicted composition of USP planets, and it is therefore extremely important to increase the still limited sample of USP planets with precise and accurate mass and density measurements. We report here the characterization of a USP planet with a period of 0.28 days around K2-141 (EPIC 246393474), and the validation of an outer planet with a period of 7.7 days in a grazing transit configuration. We derived the radii of the planets from the K2 light curve and used high-precision radial velocities gathered with the HARPS-N spectrograph for mass measurements. For K2-141b, we thus inferred a radius of 1.51 ±0.05 R and a mass of 5.08 ±0.41 M, consistent with a rocky composition and lack of a thick atmosphere. K2-141c is likely a Neptune-like planet, although due to the grazing transits and the non-detection in the RV data set, we were not able to put a strong constraint on its density. We also report the detection of secondary eclipses and phase curve variations for K2-141b. The phase variation can be modeled either by a planet with a geometric albedo of 0.30 ±0.06 in the Kepler bandpass, or by thermal emission from the surface of the planet at ∼3000 K. Only follow-up observations at longer wavelengths will allow us to distinguish between these two scenarios., United States. National Aeronautics and Space Administration (Grant NNX15AC90G), United States. National Aeronautics and Space Administration (Grant NNX17AB59G)

Published
2019

186. Coupling hydrogeophysics with hydrodynamic modelling to infer subsurface hydraulic architecture of an alluvial floodplain.

Author

Martin, J. Michael, Everett, Mark E., and Knappett, Peter S.K.

Subjects
HYDRAULIC conveying, FLOODPLAINS, HYDRODYNAMICS, WATER management, UNDERGROUND construction, GEOPHYSICAL observations
Abstract

This paper underscores the importance of spatially dense geophysical data sets for making informed decisions in water management strategies. Such decisions may require understanding how site‐specific subsurface architecture – especially hydraulic connectivity – impacts the response of a shallow aquifer to anthropogenic hydrologic disturbances (e.g. over‐pumping of a shallow aquifer). At a 0.2‐km2 alluvial floodplain site characterized by thick clay over fine sand to gravel and shale bedrock in the subtropical, sub‐humid belt of the Gulf Coast of the United States, we image an asymmetrically shaped, compartmentalized, sand‐dominated channel‐belt using electrical resistivity tomography and 31 time‐domain electromagnetic soundings probing to depths of ∼40 m and ∼90 m, respectively. Lithological interpretation and a hydrological model are developed based on the geophysical data and nearby sediment cores, where the resistivity of the groundwater is 9.1 Ωm. In a modelling scenario wherein the compartmentalized sand channel‐belt starts out dry (i.e. an over‐pumped shallow aquifer), we simulate 26 weeks of infiltration due to flooding of the surface. Preferential filling of the channel‐belt occurs through its sides rather than from above, generating a new understanding of the hydraulic connectivity around and into asymmetrically shaped, sand‐dominated channel‐belts. This insight can inform decisions about the optimal placement of shallow water wells in a heterogeneous alluvial floodplain aquifer system and also highlights the dangers of over‐pumping. [ABSTRACT FROM AUTHOR]

Published
2021
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187. A Substellar Companion to a Hot Star in K2's Campaign 0 Field

Author

Dholakia, S., primary, Dholakia, S., additional, Cody, Ann Marie, additional, Howell, Steve B., additional, Johnson, Marshall C., additional, Isaacson, Howard, additional, Everett, Mark E., additional, Ciardi, David R., additional, Howard, Andrew W., additional, and Shporer, Avi, additional

Published
2019
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190. The L 98-59 System: Three Transiting, Terrestrial-size Planets Orbiting a Nearby M Dwarf

Author

Kostov, Veselin B., primary, Schlieder, Joshua E., additional, Barclay, Thomas, additional, Quintana, Elisa V., additional, Colón, Knicole D., additional, Brande, Jonathan, additional, Collins, Karen A., additional, Feinstein, Adina D., additional, Hadden, Samuel, additional, Kane, Stephen R., additional, Kreidberg, Laura, additional, Kruse, Ethan, additional, Lam, Christopher, additional, Matthews, Elisabeth, additional, Montet, Benjamin T., additional, Pozuelos, Francisco J., additional, Stassun, Keivan G., additional, Winters, Jennifer G., additional, Ricker, George, additional, Vanderspek, Roland, additional, Latham, David, additional, Seager, Sara, additional, Winn, Joshua, additional, Jenkins, Jon M., additional, Afanasev, Dennis, additional, Armstrong, James J. D., additional, Arney, Giada, additional, Boyd, Patricia, additional, Barentsen, Geert, additional, Barkaoui, Khalid, additional, Batalha, Natalie E., additional, Beichman, Charles, additional, Bayliss, Daniel, additional, Burke, Christopher, additional, Burdanov, Artem, additional, Cacciapuoti, Luca, additional, Carson, Andrew, additional, Charbonneau, David, additional, Christiansen, Jessie, additional, Ciardi, David, additional, Clampin, Mark, additional, Collins, Kevin I., additional, Conti, Dennis M., additional, Coughlin, Jeffrey, additional, Covone, Giovanni, additional, Crossfield, Ian, additional, Delrez, Laetitia, additional, Domagal-Goldman, Shawn, additional, Dressing, Courtney, additional, Ducrot, Elsa, additional, Essack, Zahra, additional, Everett, Mark E., additional, Fauchez, Thomas, additional, Foreman-Mackey, Daniel, additional, Gan, Tianjun, additional, Gilbert, Emily, additional, Gillon, Michaël, additional, Gonzales, Erica, additional, Hamann, Aaron, additional, Hedges, Christina, additional, Hocutt, Hannah, additional, Hoffman, Kelsey, additional, Horch, Elliott P., additional, Horne, Keith, additional, Howell, Steve, additional, Hynes, Shane, additional, Ireland, Michael, additional, Irwin, Jonathan M., additional, Isopi, Giovanni, additional, Jensen, Eric L. N., additional, Jehin, Emmanuël, additional, Kaltenegger, Lisa, additional, Kielkopf, John F., additional, Kopparapu, Ravi, additional, Lewis, Nikole, additional, Lopez, Eric, additional, Lissauer, Jack J., additional, Mann, Andrew W., additional, Mallia, Franco, additional, Mandell, Avi, additional, Matson, Rachel A., additional, Mazeh, Tsevi, additional, Monsue, Teresa, additional, Moran, Sarah E., additional, Moran, Vickie, additional, Morley, Caroline V., additional, Morris, Brett, additional, Muirhead, Philip, additional, Mukai, Koji, additional, Mullally, Susan, additional, Mullally, Fergal, additional, Murray, Catriona, additional, Narita, Norio, additional, Palle, Enric, additional, Pidhorodetska, Daria, additional, Quinn, David, additional, Relles, Howard, additional, Rinehart, Stephen, additional, Ritsko, Matthew, additional, Rodriguez, Joseph E., additional, Rowden, Pamela, additional, Rowe, Jason F., additional, Sebastian, Daniel, additional, Sefako, Ramotholo, additional, Shahaf, Sahar, additional, Shporer, Avi, additional, Reyes, Naylynn Tañón, additional, Tenenbaum, Peter, additional, Ting, Eric B., additional, Twicken, Joseph D., additional, van Belle, Gerard T., additional, Vega, Laura, additional, Volosin, Jeffrey, additional, Walkowicz, Lucianne M., additional, and Youngblood, Allison, additional

Published
2019
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191. Detection of Planetary and Stellar Companions to Neighboring Stars via a Combination of Radial Velocity and Direct Imaging Techniques

Author

Kane, Stephen R., primary, Dalba, Paul A., additional, Li, Zhexing, additional, Horch, Elliott P., additional, Hirsch, Lea A., additional, Horner, Jonathan, additional, Wittenmyer, Robert A., additional, Howell, Steve B., additional, Everett, Mark E., additional, Butler, R. Paul, additional, Tinney, Christopher G., additional, Carter, Brad D., additional, Wright, Duncan J., additional, Jones, Hugh R. A., additional, Bailey, Jeremy, additional, and O’Toole, Simon J., additional

Published
2019
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195. Discovery of a Compact Companion to a Nearby Star

Author

Kane, Stephen R., primary, Dalba, Paul A., additional, Horner, Jonathan, additional, Li, Zhexing, additional, Wittenmyer, Robert A., additional, Horch, Elliott P., additional, Howell, Steve B., additional, and Everett, Mark E., additional

Published
2019
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196. Identifying Exoplanets with Deep Learning. II. Two New Super-Earths Uncovered by a Neural Network in K2 Data

Author

Dattilo, Anne, primary, Vanderburg, Andrew, additional, Shallue, Christopher J., additional, Mayo, Andrew W., additional, Berlind, Perry, additional, Bieryla, Allyson, additional, Calkins, Michael L., additional, Esquerdo, Gilbert A., additional, Everett, Mark E., additional, Howell, Steve B., additional, Latham, David W., additional, Scott, Nicholas J., additional, and Yu, Liang, additional

Published
2019
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197. Observations of Binary Stars with the Differential Speckle Survey Instrument. VIII. Measures of Metal-poor and Triple Stars from 2015 to 2018

Author

Horch, Elliott P., primary, Tokovinin, Andrei, additional, Weiss, Samuel A., additional, Löbb, János, additional, Casetti-Dinescu, Dana I., additional, Granucci, Nicole M., additional, Hess, Nicole M., additional, Everett, Mark E., additional, van Belle, Gerard T., additional, Winters, Jennifer G., additional, Nusdeo, Daniel A., additional, Henry, Todd J., additional, Howell, Steve B., additional, Teske, Johanna K., additional, Hirsch, Lea A., additional, Scott, Nicholas J., additional, Matson, Rachel A., additional, and Kane, Stephen R., additional

Published
2019
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198. The Discovery and Mass Measurement of a New Ultra-short-period Planet: EPIC 228732031b

Author

Dai, Fei, Winn, Joshua N., Gandolfi, Davide, Wang, Sharon X., Teske, Johanna K., Burt, Jennifer, Albrecht, Simon, BarragÁn, Oscar, Cochran, William D., Endl, Michael, Fridlund, Malcolm, Hatzes, Artie P., Hirano, Teruyuki, Hirsch, Lea A., Johnson, Marshall C., Justesen, Anders Bo, Livingston, John, Persson, Carina M., Prieto-arranz, Jorge, Vanderburg, Andrew, Alonso, Roi, Antoniciello, Giuliano, Arriagada, Pamela, Butler, R. p., Cabrera, Juan, Crane, Jeffrey D., Cusano, Felice, Csizmadia, SzilÁrd, Deeg, Hans, Dieterich, Sergio B., EigmÜller, Philipp, Erikson, Anders, Everett, Mark E., Fukui, Akihiko, Grziwa, Sascha, Guenther, Eike W., Henry, Gregory W., Howell, Steve B., Johnson, John Asher, Korth, Judith, Kuzuhara, Masayuki, Narita, Norio, Nespral, David, Nowak, Grzegorz, Palle, Enric, PÄtzold, Martin, Rauer, Heike, RodrÍguez, Pilar MontaÑÉs, Shectman, Stephen A., Smith, Alexis M. s., Thompson, Ian B., Van Eylen, Vincent, Williamson, Michael W., and Wittenmyer, Robert A.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, individual: EPIC 228732031 [stars], planetary systems, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a new ultra-short-period planet and summarize the properties of all such planets for which the mass and radius have been measured. The new planet, EPIC~228732031b, was discovered in {\it K2} Campaign 10. It has a radius of 1.81$^{+0.16}_{-0.12}~R_{\oplus}$ and orbits a G dwarf with a period of 8.9 hours. Radial velocities obtained with Magellan/PFS and TNG/HARPS-N show evidence for stellar activity along with orbital motion. We determined the planetary mass using two different methods: (1) the "floating chunk offset" method, based only on changes in velocity observed on the same night, and (2) a Gaussian process regression based on both the radial-velocity and photometric time series. The results are consistent and lead to a mass measurement of $6.5 \pm 1.6~M_{\oplus}$, and a mean density of $6.0^{+3.0}_{-2.7}$~g~cm$^{-3}$., Comment: 24 pages, 14 figures, accepted to AJ

Published
2017

200. Geophysical mapping of gypsum for exploration of reserves in the Nong Bua area of Thailand.

Author

Arjwech, Rungroj, Everett, Mark E., Saengchomphu, Sakhon, Somchat, Kittipong, and Pondthai, Potpreecha

Subjects
GYPSUM, SEISMIC refraction method, ELECTRICAL resistivity, ORE deposits, DRILL core analysis, CONSTRUCTION projects
Abstract

The increasing demand for gypsum as a raw material for construction projects motivates exploration for additional reserves. Electrical resistivity tomography (ERT) and seismic refraction geophysical methods, augmented with borehole and laboratory measurements on core samples, are used here to delineate the top, bottom and lateral boundaries of an important gypsum ore deposit in Thailand, an economically developing region. The gypsum-bearing formation is found throughout the study area to have an irregular upper boundary on account of karstic dissolution processes. The deeper transition from gypsum to anhydrite, however, is not constrained by the measurements. The P-wave velocity measured in the field is consistent with the core specimen measurements. The electrical resistivity of the core specimens, however, is substantially higher than the values measured in the field. The specimen measurements may depend on the presence of micro cracks, whereas electrical resistivity in the field may be affected by the enclosing clay-rich materials. [ABSTRACT FROM AUTHOR]

Published
2021
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