Physical Sciences and Mathematics Commons^™

Utilizing Post-Newtonian Expansion To Determine Parameters Of Compact Binary Black Hole Mergers, Jarrod E. Rudis

Honors College

The process of determining parameters of black hole mergers requires complicated formulae like the Einstein Field Equations (EFEs) that can only be solved numerically with the help of supercomputers. This paper sought to explore an alternative method to prediction of parameters through the use of 1st order Post-Newtonian Expansion (PNE), which is a way of approximating solutions to the EFEs. Two binary- black hole mergers, GW170814 and GW170809 were analyzed with the use of 1st order PNE to obtain the chirp mass and radiated energy parameters. These parameters were then compared with the parameters obtained using numerical solutions to the …

Dust-Gas Dynamics Driven By The Streaming Instability With Various Pressure Gradients, Stanley Antedio Baronett

UNLV Theses, Dissertations, Professional Papers, and Capstones

The radial pressure gradient (RPG), along the midplane of gaseous protoplanetary disks (PPD) – planetary nurseries – poses a severe obstacle to planet formation. Micron-sized dust grains, embedded in the disc, must quickly grow to kilometer-sized planetesimals – the building blocks of planets – before fatally drifting inwards, by RPG-induced gas drag, into a central host star. However, the RPG simultaneously powers one of the most robust processes to overcome this radial-drift barrier: the streaming instability (SI). Spontaneously triggered, the SI aerodynamically concentrates drifting dust via drag-induced, coupled interactions and feedback with the surrounding gas. In particular, the non-linear phase …

The Effects Of Winds On Accretion Disks And Spectra Of X-Ray Binaries And Active Galactic Nuclei, Shalini Ganguly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Active galactic nuclei (AGNs) and X-ray binaries (XRBs) contain at their cores supermassive black holes (SMBH), and stellar mass black holes or neutron stars, respectively. These objects bind matter gravitationally, leading to the formation of accretion disks. The accretion of matter leads to efficient conversion of gravitational potential energy into radiation. When the force and/or energy imparted by this radiation on matter exceeds the attractive force due to the local gravitational field, it leads to the launching of matter in the form of outflows or winds. These outflows produce blueshifted (and occasionally redshifted) emission or absorption components in the spectra …

Viability Of Energy And Fuel Sources For Interstellar Travel; Design And Feasibility Of The Construction Of Manned Interstellar Space Shuttles, Lukas Mittelman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The importance of proving the viability of interstellar transport and addressing its potential hazards and pitfalls is immense. If we do not look toward the future and examine what could be waiting for us, we are doing our children, our children’s children, and so on, a disservice. Here we must attempt to lay the groundwork for our future scientists, engineers, and adventurers. Asking and answering questions like, which propulsion and energy systems must we incorporate to send us through the cosmos? Will we utilize technologies known today, such as fossil fuel rockets, fission or fusion rockets, and antimatter drives (pion …

North Ecliptic Pole Merging Galaxy Catalogue, W. J. Pearson, L. E. Suelves, S. C.-C. Ho, N. Oi, S. Brough, Benne Holwerda, A. M. Hopkins, T.-C. Huang, H. S. Hwang, L. S. Kelvin, S. J. Kim, Á. R. López-Sánchez, K. Małek, C. Pearson, A. Poliszczuk, A. Pollo, V. Rodriguez-Gomez, H. Shim, Y. Toba, L. Wang

Faculty and Staff Scholarship

Aims. We aim to generate a catalogue of merging galaxies within the 5.4 sq. deg. North Ecliptic Pole over the redshift range 0.0 < z < 0.3. To do this, imaging data from the Hyper Suprime-Cam are used along with morphological parameters derived from these same data.

Methods. The catalogue was generated using a hybrid approach. Two neural networks were trained to perform binary merger non-merger classifications: one for galaxies with z < 0.15 and another for 0.15 ≤ z < 0.30. Each network used the image and morphological parameters of a galaxy as input. The galaxies that were identified as merger candidates by the network were then visually checked by experts. The resulting mergers will be used to calculate the merger fraction as a function of redshift and compared with literature results.

Results. We found that 86.3% of galaxy mergers at z < 0.15 and 79.0% of mergers at 0.15 ≤ z < 0.30 are expected to be correctly identified by the networks. Of the 34 264 galaxies classified by the neural networks, 10 195 were found to be merger candidates. Of these, 2109 were visually identified to be merging galaxies. We find that the merger fraction increases with redshift, consistent with literature results from observations and simulations, and that there is a mild star-formation rate enhancement in the merger population of a factor of 1.102 ± 0.084.

Miocene Ichnofaunas And Mammalian Communities In The Great Basin Region, Nevada And California, Annmarie R. Jones

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this dissertation is to document and interpret three new ichnofaunas and two fossil assemblages from the Neogene of Nevada and California. Ichnofossils are important for understanding behavior and geographical range of animals in the distant past and are key to locating and preserving sensitive material for future studies. I examined ichnofauna at three localities: two within the Mio-Pliocene Muddy Creek Formation of Nevada, and one within the Miocene China Ranch Beds of California. My research focuses primarily on (1) camelid and ursid ichnotaxa and how these new localities help in understanding the evolutionary history of these taxa …

The Development Of A New All-In-One Allsky Camera And Radiometer System, Ashley Suzanne Hughes

Theses and Dissertations

We developed a new all-in-one camera and radiometer system for meteor surveillance. It proved successful during its first bolide event on 13 April 2021, as reported in the journal Meteoritics and Planetary Science, volume 57, number 3, pages 575-587. The event capture produced both video and radiometric data, and with the video data we were able to calculate a trajectory and orbit, and determine the fragmentation characteristics of the meteor as it traveled through the atmosphere.

Extreme-Contrast Ratio Imaging Of Bright Star Fields Using Charge-Injection Devices, Sailee Mangesh Sawant

Theses and Dissertations

The intrinsic nature of many astronomical sources, such as exoplanets, binary and multiple star systems, circumstellar disks, and active galactic nuclei and their host galaxies, introduces challenging requirements for observational instrumentation and techniques. In each case, we encounter situations where the light from bright sources hampers our abilities to detect surrounding fainter targets. To explore and study all features of such extreme-contrast ratio (ECR) scenes, we must perform observations at the maximum possible contrast ratios. However, direct imaging of fainter objects in the vicinity of bright sources imposes limitations on the type of contrast ratios achievable using ground- and spacebased …

First Joint Observation By The Underground Gravitational-Wave Detector Kagra With Geo 600, R. Abbott, H. Abe, Fausto Acernese, K. Ackley, N. Adhikari, M. G. Benjamin, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We report the results of the first joint observation of the KAGRA detector with GEO 600. KAGRA is a cryogenic and underground gravitational-wave detector consisting of a laser interferometer with 3 km arms, located in Kamioka, Gifu, Japan. GEO 600 is a British–German laser interferometer with 600 m arms, located near Hannover, Germany. GEO 600 and KAGRA performed a joint observing run from April 7 to 20, 2020. We present the results of the joint analysis of the GEO–KAGRA data for transient gravitational-wave signals, including the coalescence of neutron-star binaries and generic unmodeled transients. We also perform dedicated searches for …

Tesing Cababilities Of Proposed Telescope Lynx Through Simulated Bubbles In The Intracluster Medium, Sierra Rose Hauck

Honors Capstone Projects and Theses

No abstract provided.

Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, R. Abbott, T. Abbott, K. Ackley, F. Acernese, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We present directed searches for continuous gravitational waves from the neutron stars in the Cassiopeia A (Cas A) and Vela Jr. supernova remnants. We carry out the searches in the LIGO detector data from the first six months of the third Advanced LIGO and Virgo observing run using the weave semicoherent method, which sums matched-filter detection-statistic values over many time segments spanning the observation period. No gravitational wave signal is detected in the search band of 20–976 Hz for assumed source ages greater than 300 years for Cas A and greater than 700 years for Vela Jr. Estimates from simulated …

Expanding The Library Of Planet Building Materials In Magrathea, Rosalie Chaleunsouck, Tristan Benally

Undergraduate Research Symposium Posters

Exoplanets are often modeled with fully-differentiated layers of iron, silicates, water, and gas. The large pressure and temperature ranges within each layer results in changes of phase and mineral equilibrium. MAGRATHEA is an open-course planet interior structure code with a large library of equations of state for planet building materials. This allows for the user to build detailed planet models and test differing measurements of the equation of state. We extend MAGRATHEA's library to include upper-mantle materials and various phases of iron cores. We show the impact of these materials on the characterization of rocky planet interiors.

Microbial Life In Deep-Subsurface Environments: The Role Of High Pressure In Biogeochemical Cycles, Cheyenne Brokaw

Undergraduate Research Symposium Posters

Ocean World: An ocean world is considered any planet or moon currently with a liquid ocean. While the deepest part of the Ocean (Mariana Trench, 11,000 mbsl, 110 Mpa) and the lithosphere host microbial life, it begs the question, How?

Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Mannuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin

Physics and Astronomy Faculty Publications and Presentations

We present a follow-up method based on supervised machine learning (ML) to improve the performance in the search of gravitational wave (GW) bursts from core-collapse supernovae (CCSNe) using the coherent WaveBurst (cWB) pipeline. The ML model discriminates noise from signal events by using a set of reconstruction parameters provided by cWB as features. Detected noise events are discarded yielding a reduction in the false alarm rate (FAR) and the false alarm probability thus enhancing the statistical significance. We tested the proposed method using strain data from the first half of the third observing run of advanced LIGO, and CCSNe GW …

Determining The Sources Of The Zodiacal Cloud Using Relative Velocities Of Dust Particles From High-Resolution Spectroscopy, Philip B. Mann Iii

Beyond: Undergraduate Research Journal

The zodiacal cloud is the Solar System debris disk in which the Earth’s orbit is located. The dust that comprises the cloud comes from cometary, asteroidal, interstellar, and other source populations, but the relative ratios have proven hard to determine. However, asteroidal and cometary particles typically have different types of orbits, with asteroidal particles having more circular and lower inclination orbits than cometary particles. Accordingly, the relative velocities of these groups of particles with respect to Earth are also different, and measurements of these relative velocities can help distinguish between the sources. The spectrum of the zodiacal light contains solar …

The Next Small Step, Samiya Henry

Undergraduate Research and Scholarship Symposium

As of right now, NASA and other space programs are estimating that by 2026, there will be people living in Space. Whether it be the Moon or Mars, one cannot have a functional society without a proper source of laws, especially since no one country has ownership over space. "One Small Step" will produce this source of laws, called the “Space Bill of Rights,” that will outline important matters like the trade of resources, medical care, government officials, and will ensure the preservation of our physical and figurative footsteps in space. This Space Bill of Rights is made up of …

The Solar-Electric Sail: Application To Interstellar Migration And Consequences For Seti, Gregory Matloff

Publications and Research

The Solar-Electric Sail accelerates by reflecting positively charged solar wind ions. If it is used to propel an interstellar migration mission, its interstellar cruise velocity relative to the home star cannot exceed the solar wind velocity. In an effort to analytically determine interstellar cruise velocity for a 107 kg generation ship, a constant solar wind velocity within the heliosphere of a Sun-like star of 600 km/s is assumed. The solar wind proton density at 1 AU is also considered constant at 10 protons per cubic centimeter. Solar wind density is assumed to decrease with the inverse square of solar distance. …

Nano-Fabricated Atomic Waveguides For Inertial Measurements, Adrian S. Orozco

Physics & Astronomy ETDs

Atom-based inertial measurement systems can measure acceleration and rotation very precisely in the laboratory. The central element of these systems is atom interferometry where the phase shifts are sensitive to inertial forces experienced by the atom. This phenomenon has been used to make atom-based gravimeters, gradiometers, and gyroscopes. Recent effort has been made to make these systems more compact which require small size, light weight, and low power (SWaP). Nano-fabricated waveguides, such as photonic waveguides or optical nanofibers, offer a promising avenue to meet these goals. They have dimensions comparable to the guided light’s wavelength producing a mode that not …

Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

We present directed searches for continuous gravitational waves from the neutron stars in the Cassiopeia A (Cas A) and Vela Jr. supernova remnants. We carry out the searches in the LIGO detector data from the first six months of the third Advanced LIGO and Virgo observing run using the weave semicoherent method, which sums matched-filter detection-statistic values over many time segments spanning the observation period. No gravitational wave signal is detected in the search band of 20–976 Hz for assumed source ages greater than 300 years for Cas A and greater than 700 years for Vela Jr. Estimates from simulated …

Reliability Of Quantum Simulation On Nisq-Era Devices, Karthik R. Chinni

Physics & Astronomy ETDs

We study the reliability of quantum simulation on Noisy intermediate-scale quantum (NISQ)-era devices in the presence of errors and imperfections, with a focus on exploring the relationship between the properties of the system being simulated and the errors in the output of the simulator. We first consider simulation of the Lipkin-Meshkov-Glick (LMG) model, which becomes chaotic in the presence of a background time-dependent perturbation. Here we show that the quantities that depend on the global structure of the phase space are robust, while other quantities that depend on the local trajectories are fragile and cannot be reliably extracted from the …

Beam-Spin Asymmetry Σ For Σ- Hyperon Photoproduction Off The Neutron, N. Zachariou, E. Munevar, B. L. Berman, P. Bydžovský, A. Cieplý, G. Feldman, Y. Ilieva, P. Nadel-Turonski, D. Skoupil, A. V. Sarantsev, D. P. Watts, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Bashkanov, M. Battaglieri, Steffen Strauch, Et. Al.

Faculty Publications

We report a new measurement of the beam-spin asymmetry, Σ, for the γn → K ⁺ Σ− reaction using quasi-free neutrons in a liquid-deuterium target. The new dataset includes data at previously unmeasured photon energy and angular ranges, thereby providing new constraints on partial wave analyses used to extract properties of the excited nucleon states. The experimental data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS), housed in Hall B of the Thomas Jefferson National Accelerator Facility (JLab). The CLAS detector measured reaction products from a liquid-deuterium target produced by an energy-tagged, linearly polarised photon beam with energies in …

Improving White Dwarfs As Chronometers With Gaia Parallaxes And Spectroscopic Metallicities, Adam Moss, Ted Von Hippel, Elliot Robinson, Kareem El-Badry, David C. Stenning, David Van Dyk, Morgan Fouesneau, Coryn A.L. Bailer-Jones, Elizabeth Jeffery, Jimmy Sargent, Isabelle Kloc, Natalie Moticska

Publications

White dwarfs (WDs) offer unrealized potential in solving two problems in astrophysics: stellar age accuracy and precision. WD cooling ages can be inferred from surface temperatures and radii, which can be constrained with precision by high-quality photometry and parallaxes. Accurate and precise Gaia parallaxes along with photometric surveys provide information to derive cooling and total ages for vast numbers of WDs. Here we analyze 1372 WDs found in wide binaries with main-sequence (MS) companions and report on the cooling and total age precision attainable in these WD+MS systems. The total age of a WD can be further constrained if its …

Measurement Of Two-Particle Correlations Of Hadrons In E+E-Collisions At Belle, Y. C. Chen, Y. J. Lee, P. Chang, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, P. Behera, K. Belous, J. Bennett, M. Bessner, T. Bilka, D. Bodrov, J. Borah, M. Bračko, P. Branchini

Faculty and Student Publications

The measurement of two-particle angular correlation functions in high-multiplicity e+e-collisions at s=10.52 GeV is reported. In this study, the 89.5 fb-1 of hadronic e+e-annihilation data collected by the Belle detector at KEKB are used. Two-particle angular correlation functions are measured in the full relative azimuthal angle (Δφ) and three units of pseudorapidity (Δη), defined by either the electron beam axis or the event-shape thrust axis, and are studied as a function of charged-particle multiplicity. The measurement in the thrust axis analysis, with mostly outgoing quark pairs determining the reference axis, is sensitive to the region of additional soft gluon emissions. …

Observing And Exploring Intrinsic Characteristics Of Type Ia Supernova, Connor Langevin

Honors Theses

No abstract provided.

Measurement Of The Branching Fraction And Cp Asymmetry For B → D ¯ 0Π Decays, T. Bloomfield, M. E. Sevior, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, J. Bennett, M. Bessner, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek

Faculty and Student Publications

We measure the branching fractions and CP asymmetries for the decays B0→D¯0π0 and B+→D¯0π+, using a data sample of 772×106 BB¯ pairs collected at the (4S) resonance with the Belle detector at the KEKB e+e- collider. The branching fractions obtained and direct CP asymmetries are B(B0→D¯0π0)=[2.70±0.06(stat)±0.10(syst)]×10-4, B(B+→D¯0π+)=[4.53±0.02(stat)±0.15(syst)]×10-3, ACP(B0→D¯0π0)=[+0.42±2.05(stat)±1.22(syst)]%, and ACP(B+→D¯0π+)=[+0.19±0.36(stat)±0.57(syst)]%. The measurements of B are the most precise to date and are in good agreement with previous results, as is the measurement of ACP(B+→D¯0π+). The measurement of ACP for B0→D¯0π0 is the first for this mode, and the value is consistent with Standard Model expectations.

The Case For Space Environmentalism, Andy Lawrence, Meredith L. Rawls, Moriba Jah, Aaron Boley, Federico Di Vruno, Simon Garrington, Michael Kramer, Samantha Lawler, James Lowenthal, Jonathan Mcdowell, Mark Mccaughrean

Astronomy: Faculty Publications

The shell bound by the Karman line at a height of ~80–100 km above the Earth’s surface and geosynchronous orbit at ~36,000 km is defined as the orbital space surrounding the Earth. It is within this region, and especially in low Earth orbit, where environmental issues are becoming urgent because of the rapid growth of the anthropogenic space object population, including satellite ‘mega-constellations’. In this Perspective, we summarize the case for considering the orbital space around the Earth as an additional ecosystem, subject to the same care and concerns, and the same broad regulations as the oceans and the atmosphere, …

Tess Hunt For Young And Maturing Exoplanets (Thyme). Vi. An 11 Myr Giant Planet Transiting A Very-Low-Mass Star In Lower Centaurus Crux, A. W. Mann, M. L. Wood, S. P. Schmidt, M. G. Barber, J. E. Owen, B. M. Tofflemire, E. R. Newton, E. E. Mamajek, J. L. Bush, G. N. Mace, A. L. Kraus, P. C. Thao, A. Vanderburg, J. Llama, C. M. Johns-Krull, L. Prato, A. G. Stahl, S.-Y. Tang, M. J. Fields, K. A. Collins, K. I. Collins, T. Gan, Eric L.N. Jensen, J. Kamler, R. P. Schwarz, E. Furlan, C. L. Gnilka, S. B. Howell, K. V. Lester, D. A. Owens, O. Suarez, D. Mekarnia, T. Guillot, L. Abe, A. H. M. J. Triaud, M. C. Johnson, R. P. Milburn, A. C. Rizzuto, S. N. Quinn, R. Kerr, G. R. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, N. M. Guerrero, A. Shporer, J. E. Schlieder, B. Mclean, B. Wohler

Physics & Astronomy Faculty Works

Mature super-Earths and sub-Neptunes are predicted to be ≃ Jovian radius when younger than 10 Myr. Thus, we expect to find 5–15 R_⊕ planets around young stars even if their older counterparts harbor none. We report the discovery and validation of TOI 1227b, a 0.85 ± 0.05 R_J (9.5 R_⊕) planet transiting a very-low-mass star (0.170 ± 0.015 M_⊙) every 27.4 days. TOI 1227's kinematics and strong lithium absorption confirm that it is a member of a previously discovered subgroup in the Lower Centaurus Crux OB association, which we designate the Musca group. We …

Physical Properties Of Brackett Emitters In The Apogee Dr17 Catalog, Elliott Khilfeh, Hunter Campbell, Kevin R. Covey, Marina Kounkel, Richard Ballentyne

WWU Honors College Senior Projects

In the process of accumulating mass (accretion), young stars channel ionized gas from the protoplanetary disk to the stellar surface along magnetic field lines. Upon impacting the photosphere, the gas cools down, recombining and emitting hydrogen spectral lines. Measuring these emission lines allows us to determine the temperature and density of the gas in those accretion streams. This then enables us to test whether those parameters depend on the accretion rate. We present measurements of equivalent widths and line ratios for Brackett (Br) 11 – 20 lines for 3366 observations of 940 pre-main sequence stars observed with APOGEE as of …

Untangling The Solar Wind And Magnetospheric Drivers Of The Radiation Belt Electrons, Simon Wing, Jay R. Johnson, Drew L. Turner, Aleksandr Y. Ukhorskiy, Alexander J. Boyd

Faculty Publications

Plain Language Summary

Many solar wind parameters correlate with one another, which complicates the causal-effect studies of solar wind driving of the magnetosphere. We use conditional mutual information, which is part of information theory, to untangle and isolate the effect of individual solar wind and magnetospheric drivers of the radiation belt electrons. For example, the solar wind density negatively correlates with electron phase space density (PSD) (average energy ∼1.6 MeV) with the response time lag of 15 hr. This has been attributed to the electron loss process such as magnetopause shadowing. The time lag suggests the time scale for this …

A Second Planet Transiting Ltt 1445a And A Determination Of The Masses Of Both Worlds, J. G. Winters, R. Cloutier, A. A. Medina, J. M. Irwin, D. Charbonneau, N. Astudillo-Defru, X. Bonfils, A. W. Howard, H. Isaacson, J. L. Bean, A. Seifahrt, J. K. Teske, J. D. Eastman, J. D. Twicken, K. A. Collins, Eric L.N. Jensen, S. N. Quinn, M. J. Payne, M. H. Kristiansen, A. Spencer, A. Vanderburg, M. Zechmeister, L. M. Weiss, S. X. Wang, G. Wang, S. Udry, I. A. Terentev, J. Stürmer, G. Stefánsson, A. Shporer, S. Shectman, R. Sefako, H. M. Schwengeler, R. P. Schwarz, N. Scarsdale, R. A. Rubenzahl, A. Roy, L. J. Rosenthal, P. Robertson, E. A. Petigura, F. Pepe, M. Omohundro, J. M. Akana Murphy, F. Murgas, T. Močnik, B. T. Montet, R. Mennickent, A. W. Mayo, B. Massey, J. Lubin, C. Lovis, P. Lewin, D. Kasper, S. R. Kane, J. M. Jenkins, D. Huber, K. Horne, M. L. Hill, P. Gorrini, S. Giacalone, B. Fulton, T. Forveille, P. Figueira, T. Fetherolf, C. Dressing, R. F. Díaz, X. Delfosse, P. A. Dalba, F. Dai, C. C. Cortés, I. J. M. Crossfield, J. D. Crane, D. M. Conti, K. I. Collins, A. Chontos, R. P. Butler, P. Brown, M. Brady, A. Behmard, C. Beard, N. M. Batalha, J.-M. Almenara

Physics & Astronomy Faculty Works

LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M_⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky …