Astrophysics and Astronomy Commons^™

Two Young Planetary Systems Around Field Stars With Ages Between 20 And 320 Myr From Tess, G. Zhou, S. N. Quinn, J. Irwin, C. X. Huang, K. A. Collins, L. G. Bouma, L. Khan, A. Landrigan, A. M. Vanderburg, J. E. Rodriguez, D. W. Latham, G. Torres, S. T. Douglas, A. Bieryla, G. A. Esquerdo, P. Berlind, M. L. Calkins, L. A. Buchhave, D. Charbonneau, K. I. Collins, J. F. Kielkopf, Eric L.N. Jensen, T.-G. Tan, R. Hart, B. Carter, C. Stockdale, C. Ziegler, N. Law, A. W. Mann, S. B. Howell, R. A. Matson, N. J. Scott, E. Furlan, R. J. White, C. Hellier, D. R. Anderson, R. G. West, G. Ricker, R. Vanderspek, S. Seager, J. M. Jenkins, J. N. Winn, I. Mireles, P. Rowden, D. A. Yahalomi, B. Wohler, C. E. Brasseur, T. Daylan, K. D. Colón

Physics & Astronomy Faculty Works

Planets around young stars trace the early evolution of planetary systems. We report the discovery and validation of two planetary systems with ages lesssim300 Myr from observations by the Transiting Exoplanet Survey Satellite (TESS). The $40\mbox{--}320$Myr old G star TOI-251 hosts a ${2.74}_{-0.18}^{+0.18}\,{R}_{\oplus }$mini-Neptune with a $4.94$day period. The $20\mbox{--}160$Myr old K star TOI-942 hosts a system of inflated Neptune-sized planets, with TOI-942b orbiting in a period of $4.32$days with a radius of ${4.81}_{-0.20}^{+0.20}\,{R}_{\oplus }$and TOI-942c orbiting in a period of $10.16$days with a radius of ${5.79}_{-0.18}^{+0.19}\,{R}_{\oplus }$. Though we cannot place either host star into a known stellar association …

Herschel Gould Belt Survey Observations Of Dense Cores In The Cepheus Flare Clouds, James Di Francesco, Jared Keown, Cassandra Fallscheer, Philippe André, Bilal Ladjelate, Vera Könyves, Alexander Men'shchikov, Shaun Stephens-Whale, Quang Nguyen-Luong, Peter Martin, Sarah Sadavoy, Stefano Pezzuto, Eleonora Fiorellino, Milena Benedettini, Nicola Schneider, Sylvain Bontemps, Doris Arzoumanian, Pedro Palmeirim, Jason M. Kirk, Derek Ward-Thompson

All Faculty Scholarship for the College of the Sciences

We present Herschel SPIRE and PACS maps of the Cepheus Flare clouds L1157, L1172, L1228, L1241, and L1251, observed by the Herschel Gould Belt Survey of nearby star-forming molecular clouds. Through modified blackbody fits to the SPIRE and PACS data, we determine typical cloud column densities of (0.5–1.0) × 10²¹ cm⁻² and typical cloud temperatures of 14–15 K. Using the getsources identification algorithm, we extract 832 dense cores from the SPIRE and PACS data at 160–500 μm. From placement in a mass versus size diagram, we consider 303 to be candidate prestellar cores, and 178 of these …

Controlling The Chaotic Motions Of An Airfoil With A Nonlinear Stiffness Using Closed-Loop Harmonic Parametric Excitation, Robert Bruce Alstrom

Faculty and Student Publications

The purpose of this research is to conduct a preliminary investigation into the possibility of suppressing the flutter and post-flutter (chaotic) responses of a two-dimensional self-excited airfoil with a cubic nonlinear stiffness (in torsion) and linear viscous damping via closed-loop harmonic parametric excitation. It was found that the initial configuration of the proposed control scheme caused the torsional/pitch dynamics to act as a nonlinear energy sink; as a result, it was identified that the mechanisms of vibration suppression are the resonance capture cascade and the short duration or isolated resonance capture. It is the isolated resonance capture that is responsible …

New Method For Beyond The Standard Model Invisible Particle Searches In Tau Lepton Decays, E. De La Cruz-Burelo, A. De Yta-Hernandez, M. Hernandez-Villanueva

Faculty and Student Publications

Motivated by models proposed to explain Standard Model anomalies, and the unprecedented τ+τ- data to be collected by the Belle II experiment during the next years, we study the kinematics of tau pair decays and propose a new method to search for lepton flavor violating processes in tau lepton decays to invisible beyond Standard Model particles, such as τ→ℓα, where ℓ is either an electron or a muon, and α is a massive particle that escapes undetected. The new method improves by one order of magnitude the expected upper limit on the τ→ℓα production in 3×1 prong tau decays and …

Chandra Spectral Measurements Of The O Supergiant Ζ Puppis Indicate A Surprising Increase In The Wind Mass-Loss Rate Over 18 Yr, David H. Cohen, Jiaming Wang , '22, V. Petit, M. A. Leutenegger, L. Dakir, C. Mayhue , '23, A. David-Uraz

Physics & Astronomy Faculty Works

New long Chandra grating observations of the O supergiant ζ Pup show not only a brightening of the X-ray emission line flux of 13 per cent in the 18 yr since Chandra’s first observing cycle, but also clear evidence – at more than 4σ significance – of increased wind absorption signatures in its Doppler-broadened line profiles. We demonstrate this with non-parametric analysis of the profiles as well as Gaussian fitting and then use line-profile model fitting to derive a mass-loss rate of 2.47 ± 0.09 × 10−6[Math Processing Error]⁠, which is a 40 per cent increase over the value obtained …

The Carmenes Search For Exoplanets Around M Dwarfs: Lp 714-47 B (Toi 442.01): Populating The Neptune Desert, S. Dreizler, I. J. M. Crossfield, D. Kossakowski, P. Plavchan, S. V. Jeffers, J. Kemmer, R. Luque, N. Espinoza, E. Pallé, K. Stassun, E. Matthews, B. Cale, J. A. Caballero, M. Schlecker, J. Lillo-Box, M. Zechmeister, S. Lalitha, A. Reiners, A. Soubkiou, B. Bitsch, M. R. Zapatero Osorio, P. Chaturvedi, A. P. Hatzes, G. Ricker, R. Vaderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, J. Aceituno, P. J. Amado, K. Barkaoui, M. Barbieri, N. M. Batalha, F. F. Bauer, B. Benneke, Z. Benkhaldoun, C. Beichman, J. Berberian, J. Burt, R. P. Butler, D. A. Caldwell, A. Chintada, A. Chontos, J. L. Christiansen, D. R. Ciardi, C. Cifuentes, K. A. Collins, K. I. Collins, D. Combs, M. Cortés-Contreras, J. D. Crane, T. Daylan, D. Dragomir, E. Esparza-Borges, P. Evans, F. Feng, E. E. Flowers, A. Fukui, B. Fulton, E. Furlan, E. Gaidos, C. Geneser, S. Giacalone, M. Gillon, E. Gonzales, V. Gorjian, C. Hellier, D. Hidalgo, A. W. Howard, S. Howell, D. Huber, H. Isaacson, E. Jehin, Eric L.N. Jensen, A. Kaminski, S. R. Kane, K. Kawauchi, J. F. Kielkopf, H. Klahr, M. R. Kosiarek, L. Kreidberg, M. Kürster, M. Lafarga, J. Livingston, D. Louie, A. Mann, A. Madrigal-Aguado, R. A. Matson, T. Mocnik, J. C. Morales, P. S. Muirhead, F. Murgas, S. Nandakumar, N. Narita, G. Nowak, M. Oshagh, P. Parviainen, V. M. Passegger, D. Pollacco, F. J. Pozuelos, A. Quirrenbach, M. Reefe, I. Ribas, P. Robertson, C. Rodríguez-López, M. E. Rose, A. Roy, A. Schweitzer, J. Schlieder, S. Shectman, A. Tanner, H. V. Şenavci, J. Teske, J. D. Twicken, J. Villasenor, S. X. Wang, L. M. Weiss, J. Wittrock, M. Yilmaz, F. Zohrabi

Physics & Astronomy Faculty Works

We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, mb = 30.8 ± 1.5M⊕, Rb = 4.7 ± 0.3 R⊕) located in the “hot Neptune desert”. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TÜBİTAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present …

Evidence For Electron Energization Accompanying Spontaneous Formation Of Ion Acceleration Regions In Expanding Plasmas, Evan M. Aguirre, Rikard Bodin, Neng Yin, Timothy N. Good, Earl E. Scime

Physics and Astronomy Faculty Publications

We report experiments conducted in an expanding argon plasma generated in the inductive mode of a helicon source in the Hot hELIcon eXperiment–Large Experiment on Instabilities and Anisotropies facility. As the neutral gas pressure increases, the supersonic ion acceleration weakens. Increasing neutral pressure also alters the radial profile of electron temperature, density, and plasma potential upstream of the plasma expansion region. Langmuir probe measurements of the electron energy probability function (EEPF) show that heating of electrons at the plasma edge by RF fields diminishes with increasing gas pressure, yielding a plasma with a centrally peaked electron temperature, and flat potential …

Investigation On The Use Of Small Aperture Telescopes For Leo Satellite Orbit Determination, Luis R. Curiel Iii

Master's Theses

The following thesis regards the use of small aperture telescopes for space domain awareness efforts. The rapidly populating space domain was motivation for the development of a new operation scheme to conduct space domain awareness feasibility studies using small telescopes. Two 14-inch Schmidt-Cassegrain Telescopes at the California Polytechnic State University and the Air Force Research Lab in Kirtland AFB, NM, in conjunction with a dedicated CCD camera and a commercial DSLR camera, were utilized to conduct optical observations on satellites in Earth orbit.

Satellites were imaged during August 2019, and from January 2020 to March 2020, resulting in the collection …

A Spitzer Survey Of Deep Drilling Fields To Be Targeted By The Vera C. Rubin Observatory Legacy Survey Of Space And Time, M. Lacy, J. A. Surace, D. Farrah, K. Nyland, J. Afonso, W. N. Brandt, D. L. Clements, C. D. P. Lagos, C. Maraston, J. Pforr, A. Sajina, M. Sako, M. Vaccari, G. Wilson, D. R. Ballantyne, Wayne A. Barkhouse, R. Brunner, R. Cane, T. E. Clarke, M. Cooper, A. Cooray, G. Covone, C. D'Andrea, A. E. Evrard, H. C. Ferguson, J. Frieman, V. Gonzalez-Perez, R. Gupta, E. Hatziminaoglou, J. Huang, P. Jagannathan, M. J. Jarvis, K. M. Jones, A. Kimball, C. Lidman, L. Lubin, L. Marchetti, P. Martini, R. G. Mcmahon, S. Mei, H. Messias, E. J. Murphy, J. A. Newman, R. Nichol, R. P. Norris, S. Oliver, I. Perez-Fournon, W. M. Peters, M. Pierre, E. Polisensky, G. T. Richards, S. E. Ridgway, H. J. A. Röttgering, N. Seymour, R. Shirley, R. Somerville, M. A. Strauss, N. Suntzeff, P. A. Thorman, E. Van Kampen, A. Verma, R. Wechsler, W. M. Wood-Vasey

Physics Faculty Publications

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will observe several Deep Drilling Fields (DDFs) to a greater depth and with a more rapid cadence than the main survey. In this paper, we describe the ‘DeepDrill’ survey, which used the Spitzer Space Telescope Infrared Array Camera (IRAC) to observe three of the four currently defined DDFs in two bands, centred on 3.6 and 4.5 μm. These observations expand the area that was covered by an earlier set of observations in these three fields by the Spitzer Extragalactic Representative Volume Survey (SERVS). The combined DeepDrill and …

Monte Carlo Simulations Of Awkward Actions, David John Amdahl

Physics & Astronomy ETDs

Time derivatives of scalar fields occur quadratically in textbook actions. A simple Legendre transformation turns the Lagrangian into a Hamiltonian that is quadratic in the momentum. The partition function over the momentum is Gaussian. Mean values of operators are basically euclidian path integrals of their classical counterparts with positive weight functions. Monte Carlo simulations can estimate such mean values. This familiar framework falls apart when the time derivatives do not occur quadratically. The Legendre transformation becomes difficult or so intractable that the Hamiltonian can’t be determined. Even if the Hamiltonian is found, it usually is so complicated that the partition …

Constraining Viscous Protoplanetary Disk Models Using Alma Kinematic Observations, Ian Rabago

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recent molecular line observations by ALMA have revealed the 3D velocity structure of protoplanetary disks, providing new insight on the mechanisms of disk accretion and ring/gap formation. Although the constant α viscous disk model has been widely used to describe the disk surface density evolution, it may not adequately describe the gas velocity at different disk heights. By carrying out viscous hydrodynamic simulations, we confirm that the vertical velocity structure varies considerably between these models. On the other hand, the surface density evolution of the disk is only dependent on the vertically integrated stress, and does not depend on a …

The Family Of (6) Hebe, Sherry Fieber-Beyer, Michael J. Gaffey

Space Studies Faculty Publications

The fundamental science question we address in this research concerns the evolution of asteroid families; more specifically, does asteroid (6) Hebe have a genetic family, and does this genetic family provide insight into the structure of (6) Hebe? Hebe has been identified dynamically and spectroscopically as the H-chondrite parent body. The H chondrites exhibit a range of metamorphisms suggesting deep excavation from the parent body, an event expected to form a family. Previously, several small H-type asteroids were identified near Hebe, supporting this possibility, but they were insufficient to test its existence. We initiated a limited spectroscopic investigation of 36 …

Closest Jupiter, Saturn Conjunction In Almost 400 Years, Erik Johnson

Natural Science Faculty

If you've been looking up in the evening over the last several months, you may have seen some rather bright objects in the southern sky. Those are the planets Jupiter and Saturn, and on December 21 they are going to appear closer together than people have seen in nearly 400 years.

The M Supergiant High-Mass X-Ray Binary 4u 1954+31, Kenneth H. Hinkle, Thomas Lebzelter, Francis C. Fekel, Oscar Straniero, Richard Joyce, Lisa Prato, Nicole Karnath, Nolan Habel

Information Systems and Engineering Management Research Publications

The X-ray binary 4U 1954+31 has been classified as a low-mass X-ray binary containing an M giant and a neutron star (NS). It has also been included in the rare class of X-ray symbiotic binaries. The Gaia parallax, infrared colors, spectral type, abundances, and orbital properties of the M star demonstrate that the cool star in this system is not a low-mass giant but a high-mass M supergiant. Thus, 4U 1954+31 is a high-mass X-ray binary (HMXB) containing a late-type supergiant. It is the only known binary system of this type. The mass of the M I is ${9}_{-2}^{+6}$ M⊙ …

Nearly 30,000 Late-Type Main-Sequence Stars With Stellar Age From Lamost Dr5, Jiajun Zhang, Terry D. Oswalt, Jingkun Zhao, Xilong Liang, Xianhao Ye, Gang Zhao

Publications

We construct a sample of nearly 30,000 main-sequence stars with 4500K < Teff < 5000K and stellar ages estimated by the chromospheric activity−age relation. This sample is used to determine the age distribution in the R − Z plane of the Galaxy, where R is the projected Galactocentric distance in the disk midplane and Z is the height above the disk midplane. As |Z| increases, the percentage of old stars becomes larger. It is known that scale-height of Galactic disk increases as R increases, which is called flare. A mild flare from R ∼ 8.0 to 9.0 kpc in stellar age distribution is found. We also find that the velocity dispersion increases with age as confirmed by previous studies. Finally we present spiral-shaped structures in Z − υZ phase space in three stellar age bins. The spiral is clearly seen in the age bin of [0, 1] Gyr, which suggests that a vertical perturbation to the disk probably took place within the last ∼ 1.0 Gyr.

Testing The Strong Equivalence Principle: Detection Of The External Field Effect In Rotationally Supported Galaxies, Stacy S. Mcgaugh, Pengfei Li

Faculty Scholarship

The strong equivalence principle (SEP) distinguishes general relativity (GR) from other viable theories of gravity. The SEP demands that the internal dynamics of a self-gravitating system under freefall in an external gravitational field should not depend on the external field strength. We test the SEP by investigating the external field effect (EFE) in Milgromian dynamics (MOND), proposed as an alternative to dark matter in interpreting galactic kinematics. We report a detection of this EFE using galaxies from the Spitzer Photometry and Accurate Rotation Curves (SPARC) sample together with estimates of the large-scale external gravitational field from an all-sky galaxy catalog. …

Tidal Locking And The Gravitational Fold Catastrophe, Andrea Ferroglia, Miguel C. N. Fiolhais

Publications and Research

The purpose of this work is to study the phenomenon of tidal locking in a pedagogical framework by analyzing the effective gravitational potential of a two-body system with two spinning objects. It is shown that the effective potential of such a system is an example of a fold catastrophe. In fact, the existence of a local minimum and saddle point, corresponding to tidally locked circular orbits, is regulated by a single dimensionless control parameter that depends on the properties of the two bodies and on the total angular momentum of the system. The method described in this work results in …

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin

LSU Doctoral Dissertations

The Advanced LIGO (aLIGO) detectors use 1064 nm lasers to measure the tiny fluctuations in spacetime that occur when gravitational waves pass through the earth. LIGO makes use of advanced coating methods and materials to limit the amount of light that scatters from the main beam, but some amount of light does scatter. This stray light can interact with surfaces inside the interferometer that are not seismically isolated and then recombine with the main beam, introducing excess noise into the gravitational wave channel. This thesis reviews the methods for modeling scattered light with ray tracing software and analytical models, for …

Exploring Hidden Structure Of The Nearby Universe And The Limits And Capabilities Of Two Neutral Hydrogen Surveys, Monica Sanchez Barrantes

Physics & Astronomy ETDs

We can use the 21 cm neutral hydrogen (HI) emission line to detect galaxies in optically obscured regions, but it is also a faint line that is difficult to detect at higher redshifts. This work presents two HI surveys. The ALFAZOA Survey maps new and predicted large-scale structure across the Galactic plane, and finds a total of 217 completely new galaxies across both of the survey phases. The completeness limits for ALFAZOA Shallow and Deep are presented. Follow-up observations of confused galaxies in ALFAZOA using the VLA determine that confusion in this survey will not cause significant deviations for the …

A Spectroscopic And Photometric Survey Of The W4 Hii Region And Its Young Stellar Population, Matt Wentzel-Long

Dissertations

The W4 HII region is home to a large number of O and B-type stars as well as the young open cluster IC 1805. OB-type produce intense photoionizing radiation and stellar winds that can induce star formation in surrounding molecular clouds and sometimes carve out large regions of decreased particle density called superbubbles. During the star formation process, young stellar objects (YSOs) are initially surrounded by circumstellar disks made of gas and dust which naturally dissipate after several million years. The dissipation of the disk is thought to occur for a variety of reasons, including photoevaporation by the encompassed protostar …