Recreating Nasa Images Using Hubble Data: Two Populations Of Stars In Messier 5,
2022
California Polytechnic State University, San Luis Obispo
Recreating Nasa Images Using Hubble Data: Two Populations Of Stars In Messier 5, Adam N. Looper
Physics
This project seeks to recreate a color photo from NASA using Hubble data that shows the two distinct populations of stars in the cluster. Although the colored image displays the two types of stars, scientists often recolor astronomical pictures for two reasons: in order to clearly define objects, or to convert an image taken outside the visible spectrum into color. Thus, overlapping Hubble images colored according to filter should verify that there are two populations of stars in Messier 5, and the colored NASA photograph is valid in highlighting the unusual distribution of stars.
Molecular Line Search In Archival Alma Imaging Of M87,
2022
Macalester College
Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li
Macalester Journal of Physics and Astronomy
We present a molecular line search in spectral imaging of the elliptical galaxy M87 using archival data from the Atacama Large Millimeter/sub-millimeter Array (ALMA). The primary goal of this project is to verify and characterize possible CO transition lines, which can be used for future studies to determine the dynamics of the system, or the mass of the supermassive black hole (BH) in the center of the galaxy. After performing extensive atmospheric modeling, we found that most of the absorption features have a corresponding atmospheric ozone transition, so it is unlikely that these features are either Galactic or extragalactic ...
Helium-Like X-Ray Line Complexes Show That The Hottest Plasma On The Zeta Supergiant Puppis Is In Its Wind,
2022
Swarthmore College
Helium-Like X-Ray Line Complexes Show That The Hottest Plasma On The Zeta Supergiant Puppis Is In Its Wind, David H. Cohen, Ariel M. Overdorff, Maurice A. Leutenegger, Marc Gagné, Veronique Petit, Alexandre David-Uraz
Earth & Space Sciences Faculty Publications
We present an analysis of Chandra grating spectra of key helium-like line complexes to put constraints on the location with respect to the photosphere of the hottest (T greater than or similar to 6 x 10(6) K) plasma in the wind of the O supergiant zeta Pup and to explore changes in the 18 yr between two sets of observations of this star. We fit two models - one empirical and one wind-shock-based - to the S XV, Si XIII, and Mg XI line complexes and show that an origin in the wind flow, above r approximate to 1.5 R ...
Monitoring The M-Dwarf Host Stars Of Tess Exoplanet Candidates: Stellar Flares And Habitability,
2022
University of Arkansas
Monitoring The M-Dwarf Host Stars Of Tess Exoplanet Candidates: Stellar Flares And Habitability, Ashley Lieber
Physics Undergraduate Honors Theses
In the search for life beyond our solar system, the study of M-dwarfs has become increasingly important due to their unique characteristics including their small size, flaring capabilities, and long lifespans. Their small size allows for exoplanet detection due to observable gravitational interactions, and the stellar flares could potentially trigger prebiotic life on exoplanets in the system. Lastly, their long lifespans may provide the conditions necessary to foster prebiotic life and the development of more complex organisms over time. Flare rate is a critical factor in determining the habitability of the exoplanet due to its potential to damage or incubate ...
Emergent Spectra Of Young X-Ray Emitting Populations Across Environments,
2022
University of Arkansas, Fayetteville
Emergent Spectra Of Young X-Ray Emitting Populations Across Environments, Alex Siebenmorgen
Physics Undergraduate Honors Theses
We construct reasonably accurate models of the X-Ray spectra of a multitude of sources in M51. We construct both average and individual models for the sources, which are split into 16 groups as the counts per source increases. Then, we create a plot to show how the model-predicted values of column density (nH) and photon index (gamma) change with luminosity. These models will be used to create an accurate X-Ray stellar energy distribution (SED) for M51, and to better understand how the SED changes with environmental factors like metallicity and star formation rate (SFR).
A Monte Carlo Method For Evaluating Empirical Gyrochronology Models And Its Application To Wide Binary Benchmarks,
2022
Embry-Riddle Aeronautical University
A Monte Carlo Method For Evaluating Empirical Gyrochronology Models And Its Application To Wide Binary Benchmarks, Tomomi Otani, Ted Von Hippel, Derek Buzasi, Terry Oswalt, Alexander Stone-Martinez, Patrice Majewski
Publications
No abstract provided.
Utilizing Post-Newtonian Expansion To Determine Parameters Of Compact Binary Black Hole Mergers,
2022
University of Maine - Main
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 ...
The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis,
2022
Louisiana State University and Agricultural and Mechanical College
The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis, Courtney Lauren Crawford
LSU Doctoral Dissertations
The rare class of stars known as the Hydrogen-deficient Carbon (HdC) stars includes the R Coronae Borealis (RCB) variables and the non-variable Dustless HdC (dLHdC) stars. These stars are believed to be formed via the merger of two white dwarf (WD) stars. They are known to exhibit many spectral peculiarities, such as partial helium burning products, enhancement of s-processed material and severe hydrogen-deficiency. In this work I explore many facets of HdC evolution. I begin by creating 18 HdC models in the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA) by merging two WD progenitors and evolving the ...
Cepheid Variable Light Curve Analysis On The Embry-Riddle 1-Meter Telescope,
2022
Embry-Riddle Aeronautical University
Cepheid Variable Light Curve Analysis On The Embry-Riddle 1-Meter Telescope, Kayla Taylor
Beyond: Undergraduate Research Journal
This report details light curve analysis for four Cepheid variable stars (Polaris, RT Aurigae, RX Aurigae, and Zeta Geminorum) using Embry-Riddle Aeronautical University's 1-meter reflecting telescope and a SBIG-STX 16803 camera with a g filter. Observations were conducted once per week during the Spring 2021 semester; at least one three-hour shift was allotted per week according to the Observational Astronomy Telescope Allocation Committee (TAC). Individual light curves for each target Cepheid were then compared to published data to analyze evidence of evolution on the Instability Strip. Although the light curves showed the sinusoidal nature of brightness oscillations, amplitudes of ...
Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry,
2022
Tennessee State University
Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson
Information Systems and Engineering Management Research Publications
We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate γ Doradus (γ Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new γ Dor variables. All exhibit sinusoidal variability with amplitudes between 6 and 65 mmag in Johnson B and periods from 0.28 to 1.13 days. All lie in the same region of the H-R diagram as our previously confirmed γ Dor stars. Of the nine systems, one is a single-lined spectroscopic binary (SB1), two are double-lined spectroscopic binaries ...
Erratum: Chandra Grating Spectroscopy Of Embedded Wind Shock X-Ray Emission From O Stars Shows Low Plasma Temperatures And Significant Wind Absorption,
2022
Swarthmore College
Erratum: Chandra Grating Spectroscopy Of Embedded Wind Shock X-Ray Emission From O Stars Shows Low Plasma Temperatures And Significant Wind Absorption, David H. Cohen, Winter Parts, Graham M. Doskoch, Jiaming Wang, Veronique Petit, Maurice A. Leutenegger, Marc Gagné
Earth & Space Sciences Faculty Publications
This is an erratum to the paper ‘ Chandra grating spectroscopy of embedded wind shock X-ray emission from O stars shows low plasma temperatures and significant wind absorption’ (2021, MNRAS, 503, 715). We present here a modest correction to the o v erall scaling of the differential emission measures (DEMs) of six O stars originally presented in Cohen et al. ( 2021 ). While working on a follow-up paper, we realized that we had incorrectly converted the bvapec spectral emission model’s normalization parameters (proportional to the emission measure per temperature bin size) to the emission measure per decade Kelvin shown in figs ...
Chandra Revisits Wr 48a: Testing Colliding Wind Models In Massive Binaries,
2022
Bulgarian Academy of Sciences
Chandra Revisits Wr 48a: Testing Colliding Wind Models In Massive Binaries, Svetozar A. Zhekov, Marc Gagné, Stephen L. Skinner
Earth & Space Sciences Faculty Publications
We present results of new Chandra High-Energy Transmission Grating (HETG) observations (2019 November-December) of the massive Wolf-Rayet binary WR 48a. Analysis of these high-quality data showed that the spectral lines in this massive binary are broadened (full width at half-maximum, FWHM = 1400 km s(-1)) and marginally blueshifted (similar to-100 km s(-1)). A direct modelling of these high-resolution spectra in the framework of the standard colliding stellar wind (CSW) picture provided a very good correspondence between the shape of the theoretical and observed spectra. Also, the theoretical line profiles are in most cases an acceptable representation of the observed ...
A Search For Analogs Of Kic 8462852 (Boyajian’S Star): A Second List Of Candidates,
2022
University of Nebraska-Lincoln
A Search For Analogs Of Kic 8462852 (Boyajian’S Star): A Second List Of Candidates, Edward G. Schmidt
Edward Schmidt Publications
In data from the Kepler mission, the normal F3V star KIC 8462852 (Boyajian’s star) was observed to exhibit infrequent dips in brightness that have not been satisfactorily explained. A previous paper reported the first results of a search for other similar stars in a limited region of the sky around the Kepler field. This paper expands on that search to cover the entire sky between declinations of +22°and +68°. Fifteen new candidates with low rates of dipping, referred to as “slow dippers” in Paper I, have been identified. The dippers occupy a limited region of the HR diagram ...
Visible Opacity Of M Dwarfs And Hot Jupiters: The Tio B³Π-X³Δ Band System,
2022
Old Dominion University
Visible Opacity Of M Dwarfs And Hot Jupiters: The Tio B³Π-X³Δ Band System, W. Doug Cameron, Peter Bernath
Chemistry & Biochemistry Faculty Publications
The TiO B3Π−X3Δ electronic transition (𝛾' system) is an important opacity source in the atmospheres of M dwarfs and hot Jupiter exoplanets. The 0–0, 1–0, and 2–1 bands of the B3Π−X3Δ band system have been analyzed using a TiO emission spectrum recorded at the McMath-Pierce Solar Telescope, operated by the National Solar Observatory at Kitt Peak, Arizona. Improved spectroscopic and equilibrium constants were determined. Line strengths were calculated from an ab initio transition-dipole moment function scaled using an experimental lifetime. A new line list for v' = 0 ...
Physical Characteristics And Classification Of The Large Amplitude Variable Star V1719 Cygni,
2022
University of Arkansas, Fayetteville
Physical Characteristics And Classification Of The Large Amplitude Variable Star V1719 Cygni, Ashley Lieber, Logan Siems, Julia Kennefick, Michael Fitzgerald
Inquiry: The University of Arkansas Undergraduate Research Journal
Pulsating stars are used as standard candles which are helpful in determining distances to stellar objects along with the relationship between their period and apparent luminosity. The focus of this study was the variable star, V1719 Cygni, which is often classified as a Delta (δ) Scuti star, but there exists debate that it should be classified as a RR Lyrae star due to its abnormal light curve and similar characteristics between the two variable star categories. Observational data was taken in 2019 using the Las Cumbres Observatory international telescope network. The resulting data were calibrated using comparison stars in the ...
A Combined Spectral And Energy Morphology Analysis Of Gamma Ray Source Hawc J2031+415 In The Cygnus Constellation,
2022
Michigan Technological University
A Combined Spectral And Energy Morphology Analysis Of Gamma Ray Source Hawc J2031+415 In The Cygnus Constellation, Ian Herzog
Dissertations, Master's Theses and Master's Reports
HAWC J2031+415 is a probable pulsar wind nebula (PWN) located in the Cygnus Cocoon region near a complex OB star cluster. First observed by the High-Energy-Gamma-Ray Astronomy (HEGRA) observatory in the TeV energy regime, the source had no apparent counterpart in lower energy ranges. Previous work using 1343 days of data from the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory has determined that three sources are present in the Region of Interest (ROI): HAWC J2031+415, HAWC J2030+409 (also known as the Cocoon), and 3HWC J2020+403 (associated with the Gamma Cygni supernova remnant) \cite{Ian_01, Binita_01}.
In this ...
Brown Dwarf Atmospheres At High Cadence And Spectral Resolution: A Speed Limit On Brown Dwarf Rotation And A Spectroscopic Atlas Of A 1050 K Atmosphere,
2021
The University of Western Ontario
Brown Dwarf Atmospheres At High Cadence And Spectral Resolution: A Speed Limit On Brown Dwarf Rotation And A Spectroscopic Atlas Of A 1050 K Atmosphere, Megan E. Tannock
Electronic Thesis and Dissertation Repository
Brown dwarfs are sub-stellar objects that form like stars but are not sufficiently massive to sustain hydrogen fusion in their cores. Characterized by cool, molecule-rich atmospheres, brown dwarfs demonstrate great diversity in spectroscopic appearance and share many properties with giant exoplanets. In this thesis I present two investigations: the first is a detailed photometric and spectroscopic study of the three most rapidly rotating brown dwarfs. The second examines a spectrum of a cool brown dwarf at unprecedented spectral resolution and signal-to-noise ratio to study the accuracy of theoretical model photospheres.
Photometric monitoring of brown dwarfs has revealed that periodic variability ...
Global 3d Radiation Hydrodynamic Simulations Of Proto-Jupiter’S Convective Envelope,
2021
University of Nevada, Las Vegas
Global 3d Radiation Hydrodynamic Simulations Of Proto-Jupiter’S Convective Envelope, Zhaohuan Zhu, Yan-Fei Jiang, Hans Baehr, Andrew N. Youdin, Philip J. Armitage, Rebecca G. Martin
Physics & Astronomy Faculty Publications
The core accretion model of giant planet formation has been challenged by the discovery of recycling flows between the planetary envelope and the disc that can slow or stall envelope accretion. We carry out 3D radiation hydrodynamic simulations with an updated opacity compilation to model the proto-Jupiter’s envelope. To isolate the 3D effects of convection and recycling, we simulate both isolated spherical envelopes and envelopes embedded in discs. The envelopes are heated at given rates to achieve steady states, enabling comparisons with 1D models. We vary envelope properties to obtain both radiative and convective solutions. Using a passive scalar ...
Establishing Α Oph As A Prototype Rotator: Precision Orbit With New Keck, Chara, And Rv Observations,
2021
University of Michigan
Establishing Α Oph As A Prototype Rotator: Precision Orbit With New Keck, Chara, And Rv Observations, Tyler Gardner, John D. Monnier, Francis C. Fekel, Michael H. Williamson, Fabien Baron, Sasha Hinkley, Michael Ireland, Adam L. Kraus, Stefan Kraus, Rachael M. Roettenbacher, Gail Schaefer, Judit Sturmann, Laszlo Sturmann, Theo A. Ten Brummelaar
Information Systems and Engineering Management Research Publications
Alpha Ophiuchi (Rasalhague) is a nearby rapidly rotating A5IV star that has been imaged by infrared interferometry. α Oph is also part of a known binary system, with a companion semimajor axis of ∼430 mas and a high eccentricity of 0.92. The binary companion provides the unique opportunity to measure the dynamical mass to compare with the results of rapid rotator evolution models. The lack of data near periastron passage limited the precision of mass measurements in previous work. We add new interferometric data from the MIRC combiner at the CHARA Array as well as new Keck adaptive optics ...
Classifying Soft X-Ray Objects In The Galactic Bulge,
2021
Louisiana State University and Agricultural and Mechanical College
Classifying Soft X-Ray Objects In The Galactic Bulge, Joshua D. Wetuski
LSU Doctoral Dissertations
The Galactic Bulge Survey (GBS) is a broad and shallow X-ray survey designed to detect quiescent X-ray binary systems in the direction of the Milky Way bulge, which include objects such as low-mass X-ray binaries, cataclysmic variables, and symbiotic binaries. LMXBs can provide constraints to the neutron star equation of state and symbiotic systems and are likely progenitors of double white dwarf systems which are themselves candidate progenitors to type Ia supernova. We seek to improve identification and classification of optical counterparts to GBS in several ways. By improving upon the original GBS, an updated catalog was created to help ...