Inclined Massive Planets In A Protoplanetary Disc: Gap Opening, Disc Breaking, And Observational Signatures,
2018
University of Nevada, Las Vegas
Inclined Massive Planets In A Protoplanetary Disc: Gap Opening, Disc Breaking, And Observational Signatures, Zhaohuan Zhu
Physics & Astronomy Faculty Research
We carry out 3D hydrodynamical simulations to study planet–disc interactions for inclined high-mass planets, focusing on the disc’s secular evolution induced by the planet. We find that, when the planet is massive enough and the induced gap is deep enough, the disc inside the planet’s orbit breaks from the outer disc. The inner and outer discs precess around the system’s total angular momentum vector independently at different precession rates, which causes significant disc misalignment. We derive the analytical formulae, which are also verified numerically, for: (1) the relationship between the planet mass and the depth/width of the induced gap, (2) …
Application Of Bradford’S Law Of Scattering On Research Publication In Astronomy & Astrophysics Of India,
2018
Bharathiar University, Coimbatore & IIT(ISM) Dhanbad
Application Of Bradford’S Law Of Scattering On Research Publication In Astronomy & Astrophysics Of India, Satish Kumar, Senthilkumar R.
Library Philosophy and Practice (e-journal)
The present study is focused on examining the application of Bradford’s law of scattering on research articles published in the field of Astronomy & Astrophysics by Indian scientist during 1988-2017. The bibliographic data was retrieved from Web of Science (WoS) bibliographic data base for different period of time. Total 18,877 journal’s article have been published by Indian scientist in the field of Astronomy & Astrophysics during 1988-2017 which was further retrieved and analyzed separately for different blocks of 10 years as well as for 30 years consolidated too. The core journal of the field was identified. The Bradford law of …
On The Apparent Absence Of Wolf–Rayet+Neutron Star Systems: The Curious Case Of Wr124,
2018
UNAM Campus Morelia
On The Apparent Absence Of Wolf–Rayet+Neutron Star Systems: The Curious Case Of Wr124, Jesus A. Toala, Lidi Oskinova, W.R. Hamann, Richard Ignace, A.A. C. Sander, H. Todt, Y.H. Chu, M. A. Guerrero, R. Hainich, R. Hainich, J. M. Terrejon
ETSU Faculty Works
Among the different types of massive stars in advanced evolutionary stages is the enigmatic WN8h type. There are only a few Wolf–Rayet (WR) stars with this spectral type in our Galaxy. It has long been suggested that WN8h-type stars are the products of binary evolution that may harbor neutron stars (NS). One of the most intriguing WN8h stars is the runaway WR 124 surrounded by its magnificent nebula M1-67. We test the presence of an accreting NS companion in WR 124 using ~100 ks long observations by the Chandra X-ray observatory. The hard X-ray emission from WR 124 with a …
The Dynamical State Of A Young Stellar Cluster,
2018
University of Missouri, St. Louis
The Dynamical State Of A Young Stellar Cluster, Timothy Sullivan
Dissertations
The dynamical state of the young star-forming cluster Rho Ophiuchi is considered, with emphasis on the L1688 cloud. Radial velocities are derived for 32 YSOs, with some being multi-epoch, using Markov-Chain Monte Carlo routines based upon the package emcee. Sources are chosen based upon their spectral index to focus on the earlier stages of star formation, in this case, Class I and Flat spectrum objects, and compared with a sample of Class II and III objects from the same embedded cluster. It is found that the radial velocity dispersion for these younger objects is ∆v = 2.8 ± 0.6 km …
Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run,
2018
The University of Texas Rio Grande Valley
Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Robert Stone, Darkhan Tuyenbayev, Wenhui Wang
Physics & Astronomy Faculty Publications
We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2 M-1.0 M using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2 M, 0.2 M) ultracompact binaries to be less than 1.0×106 Gpc-3 yr-1 and the coalescence rate of a similar distribution of (1.0 M, 1.0 M) ultracompact binaries to be less than 1.9×104 Gpc-3 yr-1 (at 90% confidence). Neither black holes nor neutron stars are expected to …
The Hst Pancet Program: Hints Of Na I And Evidence Of A Cloudy Atmosphere For The Inflated Hot Jupiter Wasp-52b,
2018
Harvard-Smithsonian Center for Astrophysics
The Hst Pancet Program: Hints Of Na I And Evidence Of A Cloudy Atmosphere For The Inflated Hot Jupiter Wasp-52b, Munazza K. Alam, Nikolay Nikolov, Mercedes López-Morales, David K. Sing, Jayesh M. Goyal, Gregory W. Henry, Jorge Sanz-Forcada, Michael H. Williamson, Thomas M. Evans, Hannah R. Wakeford, Giovanni Bruno, Gilda E. Ballester, Kevin B. Stevenson, Nikole K. Lewis, Joanna K. Barstow, Vincent Bourrier, Lars A. Buchhave, David Ehrenreich, Antonio García Muñoz
Information Systems and Engineering Management Research Publications
We present an optical to near-infrared transmission spectrum of the inflated hot Jupiter WASP-52b using three transit observations from the Space Telescope Imaging Spectrograph mounted on the Hubble Space Telescope, combined with Spitzer/Infrared Array Camera photometry at 3.6 and 4.5 μm. Since WASP-52 is a moderately active (log(Lx/Lbol) = −4.7) star, we correct the transit light curves for the effect of stellar activity using ground-based photometric monitoring data from the All-sky Automated Survey for Supernovae (ASAS-SN) and Tennessee State University's Automatic Imaging Telescope. We bin the data in 38 spectrophotometric light curves from 0.29 to 4.5 μm and measure the …
Mirach’S Goblin: Discovery Of A Dwarf Spheroidal Galaxy Behind The Andromeda Galaxy,
2018
Universität Heidelberg
Mirach’S Goblin: Discovery Of A Dwarf Spheroidal Galaxy Behind The Andromeda Galaxy, David Martínez-Delgado, Eva Grebel, Behnam Javanmardi, Walter Boschin, Nicolas Longeard, Julio Carballo-Bello, Dmitry Makarov, Michael Beasley, Giuseppe Donatiello, Martha Haynes, Duncan Forbes, Aaron Romanowsky
Faculty Publications
Context. It is of broad interest for galaxy formation theory to carry out a full inventory of the numbers and properties of dwarf galaxies, both satellite and isolated, in the Local Volume.Aims. Ultra-deep imaging in wide areas of the sky with small amateur telescopes can help to complete the census of these hitherto unknown low-surface-brightness galaxies, which cannot be detected by the current resolved stellar population and HI surveys. We report the discovery of Donatiello I, a dwarf spheroidal galaxy located one degree from the star Mirach (β And) in a deep image taken with an amateur telescope.Methods. The color-magnitude …
Covariations Of Chromospheric And Photometric Variability Of The Young Sun Analogue Hd 30495: Evidence For And Interpretation Of Mid-Term Periodicities,
2018
Harvard-Smithsonian Center for Astrophysics
Covariations Of Chromospheric And Photometric Variability Of The Young Sun Analogue Hd 30495: Evidence For And Interpretation Of Mid-Term Periodicities, Willie Soon, Victor M. Velasco Herrera, Rodolfo G. Cionco, S. Qiu, Sallie Baliunas, Ricky Egeland, Gregory W. Henry, Ivanka Charvátová
Information Systems and Engineering Management Research Publications
This study reports the synchronization between the chromospheric and photometric variability at time-scale of about 1.6–1.8 yr as observed for the young, rapidly rotating solar analogue HD 30495. In addition, HD 30495 may be presenting evidence of surface differential rotation at time-scales of about 11 d and 21 d, as well as the sunspot-like decadal cycles at 11–12 yr or so. We apply a new gapped wavelet method of time–frequency analysis for studying the variability in a new composite of the chromospheric S-index (1967–2018) and the longest photometric Δ(b + y)/2 index (1993–2018). We discuss and interpret our results in …
Angular Momentum And Galaxy Formation Revisited: Scaling Relations For Disks And Bulges,
2018
Space Telescope Science Institute
Angular Momentum And Galaxy Formation Revisited: Scaling Relations For Disks And Bulges, S. Michael Fall, Aaron Romanowsky
Faculty Publications
We show that the stellar specific angular momentum j, mass M, and bulge fraction of normal galaxies of all morphological types are consistent with a simple model based on a linear superposition of independent disks and bulges. In this model, disks and bulges follow scaling relations of the form and with but offset from each other by a factor of 8 ± 2 over the mass range . Separate fits for disks and bulges alone give and , respectively. This model correctly predicts that galaxies follow a curved 2D surface in the 3D space of , , and . We …
The Circular Restricted Four-Body Problem With Triaxial Primaries And Variable Infinitesimal Mass,
2018
Majmaah University
The Circular Restricted Four-Body Problem With Triaxial Primaries And Variable Infinitesimal Mass, Abdullah A. Ansari
Applications and Applied Mathematics: An International Journal (AAM)
This paper investigates the circular restricted four-body problem in which three primaries are taken as triaxial rigid body which are placed at the vertices of an equilateral triangle and the fourth infinitesimal body is varying its mass with time. We used the Jeans law to determine equations of motion and then evaluated the Jacobi integral. In the next section, we have performed the computational work to draw the graphs of the equilibrium points in different planes, zero velocity curves, surfaces and the Newton-Raphson basins of attraction with the variations of the triaxiality parameters. Finally, we have examined the linear stability …
Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay,
2018
University of Arkansas, Fayetteville
Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern
Biological Sciences Undergraduate Honors Theses
Methanogens, some of Earth’s most primitive prokaryotic organisms, are candidates for possible life forms capable of inhabiting Mars. Specifically, four different species (Methanobacterium formicicum, Methanococcus maripaludis, Methanosarcina barkeri, Methanothermobacter wolfeii) were analyzed for their tolerance to the presence of illite clay. Illite is a crystalline mineral that has been identified from regions of Mars’s surface. Results indicated that all four species grew with some success in the illite at different concentrations. This experimentation with methanogens’ abilities to survive and reproduce in the presence of illite allows for a more accurate understanding of the potential capability of microbial …
Gaps And Rings In An Alma Survey Of Disks In The Taurus Star-Forming Region,
2018
Peking University
Gaps And Rings In An Alma Survey Of Disks In The Taurus Star-Forming Region, Feng Long, Paola Pinilla, Gregory J. Herczeg, Daniel Harsono, Giovanni Dipierro, Ilaria Pascucci, Nathan Hendler, Marco Tazzari, Enrico Ragusa, Colette Salyk, Suzan Edwards, Giuseppe Lodato, Gerrit Van De Plas, Doug Johnstone, Yao Liu, Yann Boehler, Sylvie Cabrit, Carlo F. Manara, Francois Menard, Gijs D. Mulders, Brunella Nisini, William J. Fischer, Elisabetta Rigliaco, Andrea Banzatti, Henning Avenhaus, Michael Gully-Santiago
Astronomy: Faculty Publications
Rings are the most frequently revealed substructure in ALMA dust observations of protoplanetary disks, but their origin is still hotly debated. In this paper, we identify dust substructures in 12 disks and measure their properties to investigate how they form. This subsample of disks is selected from a high-resolution (∼ 0.1200) ALMA 1.33 mm survey of 32 disks in the Taurus star-forming region, which was designed to cover a wide range of sub-mm brightness and to be unbiased to previously known substructures. While axisymmetric rings and gaps are common within our sample, spiral patterns and high contrast azimuthal asymmetries are …
Book Review: Life On Mars: What To Know Before We Go,
2018
Embry-Riddle Aeronautical University
Book Review: Life On Mars: What To Know Before We Go, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of Life on Mars: what to know before we go. Princeton, 2018. 302p index ISBN 9780691180533, $29.95; ISBN 9781400889945 ebook, contact publisher for price.
A Plausible Resolution To Hilbert’S Failed Attempt To Unify Gravitation & Electromagnetism,
2018
University of New Mexico
A Plausible Resolution To Hilbert’S Failed Attempt To Unify Gravitation & Electromagnetism, Florentin Smarandache, Victor Christianto, Robert Neil Boyd
Branch Mathematics and Statistics Faculty and Staff Publications
In this paper, we explore the reasons why Hilbert’s axiomatic program to unify gravitation theory and electromagnetism failed and outline a plausible resolution of this problem. The latter is based on Gödel’s incompleteness theorem and Newton’s aether stream model.
Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering,
2018
Old Dominion University
Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, B. Wang
Physics Faculty Publications
We survey the current phenomenological status of semi-inclusive deeply inelastic scattering at moderate hard scales and in the limit of very large transverse momentum. As the transverse momentum becomes comparable to or larger than the overall hard scale, the differential cross sections should be calculable with fixed order perturbative QCD (pQCD) methods, while small transverse momentum (transverse-momentum-dependent factorization) approximations should eventually break down. We find large disagreement between HERMES and COMPASS data and fixed order calculations done with modern parton densities, even in regions of kinematics where such calculations should be expected to be very accurate. Possible interpretations are suggested.
Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories,
2018
University of Louisville
Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories, Benne W. Holwerda, J. S. Bridge, R. Ryan, M. A. Kenworthy, N. Pirzkal, M. Andersen, S. Wilkins, R. Smit, S. R. Bernard, T. Meshkat, R. Steele, R. C. Bouwens
Faculty and Staff Scholarship
Aims. We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. Methods. We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color-color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and …
Cm-Wavelength Obserations Of Mwc 758: Resolved Dust Trapping In A Vortex,
2018
Universidad de Chile
Cm-Wavelength Obserations Of Mwc 758: Resolved Dust Trapping In A Vortex, Simon Casassus, Sebastián Marino, Wladimir Lyra, Clément Baruteau, Matías Vidal, Alwyn Wootten, Sebastián Pérez, Felipe Alarcon, Marcelo Barraza, Miguel Cárcamo, Ruobing Dong, Anibal Sierra, Zhaohuan Zhu, Luca Ricci, Valentin Christiaens, Lucas Cieza
Physics & Astronomy Faculty Research
The large crescents imaged by ALMA in transition discs suggest that azimuthal dust trapping concentrates the larger grains, but centimetre–wavelengths continuum observations are required to map the distribution of the largest observable grains. A previous detection at ∼1 cm of an unresolved clump along the outer ring of MWC 758 (Clump 1), and buried inside more extended sub-mm continuum, motivates followup VLA observations. Deep multiconfiguration integrations reveal the morphology of Clump 1 and additional cm-wave components that we characterize via comparison with a deconvolution of recent 342 GHz data (∼1 mm). ... See full text for complete abstract.
Detection Of Helium In The Atmosphere Of The Exo-Neptune Hat-P-11b,
2018
University of Chicago
Detection Of Helium In The Atmosphere Of The Exo-Neptune Hat-P-11b, Megan Mansfield, Jacob L. Bean, Antonija Oklopčić, Laura Kreidberg, Jean-Michel Désert, Eliza M. R. Kempton, Michael R. Line, Jonathan J. Fortney, Gregory W. Henry, Matthias Mallonn, Kevin B. Stevenson, Diana Dragomir, Romain Allart, Vincent Bourrier
Information Systems and Engineering Management Research Publications
The helium absorption triplet at a wavelength of 10833 Å has been proposed as a way to probe the escaping atmospheres of exoplanets. Recently this feature was detected for the first time using Hubble Space Telescope (HST) WFC3 observations of the hot Jupiter WASP-107b. We use similar HST/WFC3 observations to detect helium in the atmosphere of the hot Neptune HAT-P-11b at the 4σ confidence level. We compare our observations to a grid of 1D models of hydrodynamic escape to constrain the thermospheric temperatures and mass loss rate. We find that our data are best fit by models with high mass …
An Optical Transmission Spectrum For The Ultra-Hot Jupiter Wasp-121b Measured With The Hubble Space Telescope,
2018
Massachusetts Institute of Technology
An Optical Transmission Spectrum For The Ultra-Hot Jupiter Wasp-121b Measured With The Hubble Space Telescope, Thomas M. Evans, David K. Sing, Jayesh M. Goyal, Nikolay Nikolov, Mark S. Marley, Kevin Zahnle, Gregory W. Henry, Joanna K. Barstow, Munazza K. Alam, Jorge Sanz-Forcada, Tiffany Kataria, Nikole K. Lewis, Panayotis Lavvas, Gilda E. Ballester, Lotfi Ben-Jaffel, Sarah D. Blumenthal, Vincent Bourrier, Benjamin Drummond, Antonio García Muñoz, Mercedes López-Morales, Pascal Tremblin, David Ehrenreich, Hannah R. Wakeford, Lars A. Buchhave, Alain Lecavelier Des Etangs, Éric Hébrard, Michael H. Williamson
Information Systems and Engineering Management Research Publications
We present an atmospheric transmission spectrum for the ultra-hot Jupiter WASP-121b, measured using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. Across the 0.47–1 wavelength range, the data imply an atmospheric opacity comparable to—and in some spectroscopic channels exceeding—that previously measured at near-infrared wavelengths (1.15–1.65 ). Wavelength-dependent variations in the opacity rule out a gray cloud deck at a confidence level of 3.7σ and may instead be explained by VO spectral bands. We find a cloud-free model assuming chemical equilibrium for a temperature of 1500 K and a metal enrichment of 10–30× solar matches …
The Dragonfly Nearby Galaxies Survey. V. Hst/Acs Observations Of 23 Low Surface Brightness Objects In The Fields Of Ngc 1052, Ngc 1084, M96, And Ngc 4258,
2018
Yale University
The Dragonfly Nearby Galaxies Survey. V. Hst/Acs Observations Of 23 Low Surface Brightness Objects In The Fields Of Ngc 1052, Ngc 1084, M96, And Ngc 4258, Yotam Cohen, Pieter Van Dokkum, Shany Danieli, Aaron Romanowsky, Roberto Abraham, Allison Merritt, Jielai Zhang, Lamiya Mowla, J. Diederik Kruijssen, Charlie Conroy, Asher Wasserman
Faculty Publications
We present Hubble Space Telescope/Advanced Camera for Surveys (ACS) imaging of 23 very low surface brightness (μ e,V ~ 25–27.5) galaxies detected in the fields of four nearby galaxy groups. These objects were selected from deep optical imaging obtained with the Dragonfly Telephoto Array. Seven are newly identified, while most of the others had been seen previously in visual surveys of deep photographic plates and more recent surveys. Few have previously been studied in detail. From the ACS images, we measure distances to the galaxies using both the tip of the red giant branch method and the surface brightness fluctuations …
