Stars, Interstellar Medium and the Galaxy Commons^™

Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, Terry D. Oswalt, Derek Buzasi, Tomomi Otani

Publications

We are determining rotation periods for an ensemble of over 100 wide non-interacting binary stars in the K2 Campaign 5 field that contain two main sequence dwarfs, as well as a smaller sample containing at least one white dwarf component. Observations of such coeval pairs provide the basis for our new investigation of rotation-based age determinations. Such “gyrochronology” ages can achieve a precision that exceeds most other current method of stellar age determination. Here we present a status report on our analysis of the light curves extracted from the K2 Campaign 5 field.

Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, T. D. Oswalt, T. Otani, A. Stone-Martinez, P. Majewski, D. Buzasi

Publications

Essential to understanding the history of the Galaxy’s stellar populations, ages are among the most difficult to measure properties of stars. Accurate stellar ages would provide key leverage on problems ranging from the habitability of exoplanets to the Galaxy’s chemical evolution and age. Gyrochronology, the empirical relation between rotation and age, is believed to be among the best current methods of stellar age determination. Using several hundred wide non-interacting binaries identified in the Kepler mission “K2” extended mission fields we are testing this paradigm. Such wide pairs afford a unique opportunity to unravel and calibrate the effects of mass, rotation, …

Mayo Dark Skies Park: A Virtual Experience, Mayo Dark Skies Community Group, Frank Prendergast

Datasets

The Mayo Dark Skies Community Group, in collaboration with the Dublin Institution of Technology, is pleased to launch a digital virtual experience of the Mayo Dark Sky Park. Following its designation as an International Dark Sky Park (Gold Tier), it is now possible to experience a part of this magnificent and pristine skyscape on your computer. This has been made possible using open source software (Stellarium http://www.stellarium.org/) and a specially commissioned digital panorama of the horizon surrounding the Ballycroy National Park Visitor Centre.

Stellarium is an open source planetarium for your computer and shows a fully realistic …

Using Student Characteristics, Student Spatial-Content Knowledge, And Teacher Spatial-Content Knowledge To Predict Student Spatial-Content Knowledge Of Lunar Phases, Kyle A. Curry

Theses and Dissertations--Science, Technology, Engineering, and Mathematics (STEM) Education

Student demographic characteristics of gender and race/ethnicity, students’ spatial-content knowledge as measured by pre-instructional performance on the Lunar Phases Concept Inventory (LPCI) (Lindell & Olsen), and post-instructional performance on the Purdue Visualization of Rotations Test (PSVT) (Bodner & Guay, 1997), and teachers’ spatial-content knowledge as measured by the two assessments were considered to predict students’ overall understanding of lunar phases as measured by post-instructional results on the LPCI. A mixed modeling approach was used in a hierarchal manner to evaluate the student learning outcomes. Results showed that student gender was not a significant predictor of post-instructional student performance, but students …

O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, Tomomi Otani, Terry Oswalt, Alexander Stone-Martinez, Dana Singh, Kenneth Sampson, Aliyah Khan, Austin Seepersad, Caila Deabreu, Adam Moss, Claudia Morello

Publications

PG 1219 + 534 (KY Uma) is a subdwarf B pulsating star with multiple periodicities between 120 – 175 s. PG 1219 + 534 was monitored for 90 hours during 2010-1 and 2016 using the 0.9 m SARA-KP telescope at Kitt Peak National Observatory (KPNO) in Arizona and the 0.8m Ortega telescope at Florida Institute of Technology in Melbourne, Florida. So far, the most promising theory for the origin of subdwarf B (sdB) stars is that they result from binary mass transfer near the Helium Flash stage of evolution. The observations of PG 1219 + 534 reported here are part …

First Performance Results Of A New Field-Widened Spatial Heterodyne Spectrometer For Geocoronal Hα Research, D. D. Gardner, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig, S. M. Nossal, L. M. Haffner

Publications

A new, high-resolution field-widened spatial heterodyne spectrometer (FW-SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry-Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW-SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts.Coincident Hα observations by FW-SHS and PBO FPI were obtained over similar integration times, …

Sdss-Iv Manga: Spatially Resolved Star Formation Histories In Galaxies As A Function Of Galaxy Mass And Type, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, J. Lian, M. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann, D. P. Schneider

Physics and Astronomy Faculty Publications

We study the internal gradients of stellar population properties within 1.5 R_e for a representative sample of 721 galaxies, with stellar masses ranging between 10⁹ M_⊙ and 10^11.5 M_⊙ from the SDSS-IV MaNGA Integral-Field-Unit survey. Through the use of our full spectral fitting code firefly, we derive light- and mass-weighted stellar population properties and their radial gradients, as well as full star formation and metal enrichment histories. We also quantify the impact that different stellar population models and full spectral fitting routines have on the derived stellar population properties and the radial gradient measurements. In …

Infrared Spectroscopy Of Symbiotic Stars. Xi. Orbits For Southern S-Type Systems: Hen 3-461, Sy Mus, Hen 3-828, And Ar Pav, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood

Information Systems and Engineering Management Research Publications

Employing new infrared radial velocities, we have computed spectroscopic orbits of the cool giants in four southern S-type symbiotic systems. The orbits for two of the systems, Hen 3-461 and Hen 3-828, have been determined for the first time, while orbits of the other two, SY Mus and AR Pav, have previously been determined. For the latter two systems, we compare our results with those in the literature. The low mass of the secondary of SY Mus suggests that it has gone through a common envelope phase. Hen 3-461 has an orbital period of 2271 days, one of the longest …

Sdss-Iv Manga: The Impact Of Diffuse Ionized Gas On Emission-Line Ratios, Interpretation Of Diagnostic Diagrams And Gas Metallicity Measurements, Kai Zhang, Renbin Yan, Kevin Bundy, Matthew Bershady, L. Matthew Haffner, René Walterbos, Roberto Maiolino, Christy Tremonti, Daniel Thomas, Niv Drory, Amy Jones, Francesco Belfiore, Sebastian F. Sánchez, Aleksandar M. Diamond-Stanic, Dmitry Bizyaev, Christian Nitschelm, Brett Andrews, Jon Brinkmann, Joel R. Brownstein, Edmond Cheung, Cheng Li, David R. Law, Alexandre Roman Lopes, Daniel Oravetz, Kaike Pan, Thaisa Storchi Bergmann, Audrey Simmons

Physics and Astronomy Faculty Publications

Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed by Mapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low Σ_Hα regions display enhanced [S II]/Hα, [N II]/Hα, [O II]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and Σ_Hα. In line ratio diagnostic diagrams, contamination by DIG moves H II …

A Trip To The Cataclysmic Binary Zoo: Detailed Follow-Up Of 35 Recently Discovered Systems, John R. Thorstensen, Erek H. Alper, Kathryn E. Weil

Dartmouth Scholarship

We report follow-up studies of 35 recently discovered cataclysmic variables (CVs), 32 of which were found in large, automated synoptic sky surveys. The objects were selected for observational tractability. For 34 of the objects, we present mean spectra and spectroscopic orbital periods, and for one more we give an eclipse-based period. Thirty-two of the period determinations are new, and three of these refine published estimates based on superhump periods. The remaining three of our determinations confirm previously published periods. Twenty of the stars are confirmed or suspected dwarf novae with periods shorter than 3 hr, but we also find three …

Why Most Bright Stars Are Binary But Most Dim Stars Are Single: A Simple Qualitative Explanation, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

It is known that most visible stars are binary: they have a nearby companion star, and these two stars orbit around each other. Based on this fact, until recently, astronomers believed that, in general, most stars are binary. A few years ago, a surprising paper showed that while most bright stars are indeed binary, most dim stars are single. In this paper, we provide a simple qualitative explanation for this empirical fact.

A Search For Very High-Energy Gamma Rays From The Missing Link Binary Pulsar J1023+0038 With Veritas, P. T. Reynolds, Et Al

Physical Sciences Publications

The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259–63/LS 2883, making it an ideal candidate for the study of high-energy nonthermal emission. It has been the subject of multiwavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high energy (VHE) gamma-ray observations carried out by the Very Energetic Radiation Imaging Telescope Array System before and after this change of state. Searches for steady and pulsed emission of both data …

Orbital Solutions And Absolute Elements Of The Massive Algol Binary Et Tauri, Richard M. Williamon, Horace Dale, Charles L. Evavold, Alexander Langoussis, Francis C. Fekel, Matthew W. Muterspaugh, Stephen Williams, Kate Napier, James R. Sowell

Information Systems and Engineering Management Research Publications

We acquired differential UBV photoelectric photometry and radial velocities of the relatively bright, understudied, massive Algol binary ET Tau and utilized the Wilson-Devinney (WD) analysis program to obtain a simultaneous solution of these observations. To improve the orbital ephemeris, the V measurements from the ASAS program were also analyzed. Because of the very rapid rotation of the significantly more massive and hotter component (B2/3 spectral class), only radial velocities of the secondary component, which has a ∼B7 spectral class, could be measured. We derive masses of ${M}_{1}=14.34\pm 0.28\,{M}_{\odot }$ and ${M}_{2}=6.339\pm 0.117\,{M}_{\odot }$ and equal-volume radii of ${R}_{1}=6.356\pm 0.056\,{R}_{\odot }$ …

Very High Energy Observations Of The Binaries V 404 Cyg And 4u 0115+634 During Giant X-Ray Outbursts, P. T. Reynolds, Et Al

Physical Sciences Publications

Transient X-ray binaries produce major outbursts in which the X-ray flux can increase over the quiescent level by factors as large as 107. The low-mass X-ray binary V 404 Cyg and the high-mass system 4U 0115+634 underwent such major outbursts in 2015 June and October, respectively. We present here observations at energies above hundreds of GeV with the VERITAS observatory taken during some of the brightest X-ray activity ever observed from these systems. No gamma-ray emission has been detected by VERITAS in 2.5 hr of observations of the microquasar V 404 Cyg from 2015, June 20–21. The upper flux limits …

Sdss-Iv Manga: Stellar Population Gradients As A Function Of Galaxy Environment, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, M. A. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann

Physics and Astronomy Faculty Publications

We study the internal radial gradients of stellar population properties within 1.5 R_e and analyse the impact of galaxy environment. We use a representative sample of 721 galaxies with masses ranging between 10⁹ M_⊙ and 10^11.5 M_⊙ from the SDSS-IV survey MaNGA. We split this sample by morphology into early-type and late-type galaxies. Using the full spectral fitting code firefly, we derive the light and mass-weighted stellar population properties, age and metallicity, and calculate the gradients of these properties. We use three independent methods to quantify galaxy environment, namely the Nth nearest neighbour, the …

The Growth Of The Central Region By Acquisition Of Counterrotating Gas In Star-Forming Galaxies, Yan-Mei Chen, Yong Shi, Christy A. Tremonti, Matt Bershady, Michael Merrifield, Eric Emsellem, Yi-Fei Jin, Song Huang, Hai Fu, David A. Wake, Kevin Bundy, David Stark, Lihwai Lin, Maria Argudo-Fernandez, Thaisa Storchi Bergmann, Dmitry Bizyaev, Joel Brownstein, Martin Bureau, John Chisholm, Niv Drory, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, Alexandre Roman Lopes, Kai-Ke Pan, Rogemar A Riffel, Daniel Thomas, Lan Wang, Renbin Yan

Physics and Astronomy Faculty Publications

Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Here, based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations …

Very Low-Mass Stellar And Substellar Companions To Solar-Like Stars From Marvels. Vi. A Giant Planet And A Brown Dwarf Candidate In A Close Binary System Hd 87646, Bo Ma, Jian Ge, Alex Wolszczan, Matthew W. Muterspaugh, Brian Lee, Gregory W. Henry, Donald P. Schneider, Eduardo L. Martín, Andrzej Niedzielski, Jiwei Xie, Scott W. Fleming, Neil Thomas, Michael Williamson, Zhaohuan Zhu, Eric Agol, Dmitry Bizyaev, Luiz Nicolaci Da Costa, Peng Jiang, Aldo Fabricio Martinez Fiorenzano, Jonay I. González Hernández, Pengcheng Guo, Nolan Grieves, Rui Li, Jane Liu, Suvrath Mahadevan, Tsevi Mazeh, Duy Cuong Nguyen, Martin Paegert, Sirinrat Sithajan, Keivan Stassun, Sivarani Thirupathi, Julian C. Van Eyken, Xiaoke Wan, Ji Wang, John P. Wisniewski, Bo Zhao, Shay Zucker

Information Systems and Engineering Management Research Publications

We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using the Exoplanet Tracker at the Kitt Peak National Observatory, the High Resolution Spectrograph at the Hobby Eberley telescope, the "Classic" spectrograph …

Fundamental Parameters Of The Lowest Mass Stars To The Highest Mass Planets, Joseph C. Filippazzo

Dissertations, Theses, and Capstone Projects

The physical and atmospheric properties of ultracool dwarfs are deeply entangled due to the degenerate effects of mass, age, metallicity, clouds and dust, activity, rotation, and possibly formation mechanism on their observed properties. Accurate fundamental parameters for a wide range of substellar objects are crucial to testing stellar and planetary formation theories. To determine these quantities, we construct flux-calibrated spectral energy distributions (SEDs) for 234 M, L, T, and Y dwarfs and calculate bolometric luminosity (L_bol), effective temperature (T_eff), mass, surface gravity, radius, spectral indexes, synthetic photometry, and bolometric corrections (BCs) for each object. We use …

"Blinded By The Lines: Mid-Ir Spectra Of Mira Variables Taken With Spitzer", Dana Baylis-Aguirre, Michelle J. Creech-Eakman, Donald G. Luttermoser, Tina Gueth

ETSU Faculty Works

We present preliminary analysis of mid-infrared spectra of M-type and C-type Mira variables. Due to the brightness of this sample, it is straightforward to monitor changes with phase in the infrared spectral features of these regular pulsators. We have spectra of 25 Mira variables, taken with phase, using the Spitzer Infrared Spectrograph (IRS) high-resolution module. Each star has multiple spectra obtained over a one-year period from 2008-09. This is a rich, unique data set due to multiple observations of each star and the high signal-to-noise ratio from quick exposure times to prevent saturation of the IRS instrument. This paper focuses …

Torsional Oscillations And Observed Rotational Period Variations In Early-Type Stars, Jiří Krtička, Zdeněk Mikulášek, Gregory W. Henry, Petr Kurfürst, Marian Karlický

Information Systems and Engineering Management Research Publications

Some chemically peculiar stars in the upper main sequence show rotational period variations of unknown origin. We propose that these variations are a consequence of the propagation of internal waves in magnetic rotating stars that lead to the torsional oscillations of the star. We simulate the magnetohydrodynamic waves and calculate resonant frequencies for two stars that show rotational variations: CU Vir and HD 37776. We provide updated analyses of rotational period variations in these stars and compare our results with numerical models. For CU Vir, the length of the observed rotational period cycle, | $\mathit {\Pi }=67.6(5)$ | yr, can …