Physical Sciences and Mathematics Commons^™

There Is Life On Mars, Colin M. Johnston, Olivier B. Cohen

CAFE Symposium 2024

An extensive research project that involved the research of multiple major experiments and discoveries about possible life on the planet Mars. Facts, Data, conspiracies and theories have all been taken into account and provided in this project.

Extraterrestrial Life: The Possibility Of A Human-Alien Interaction, Ariana M. Piscoya

CAFE Symposium 2024

We all have heard of at least one case where someone assured having seen a flying extraterrestrial object. There are thousands of thousands of videos we can find online that “prove” the existence of aliens. In the hypothetical case where aliens are really out there, why haven't we been able to talk to them and look at them face-to-face? A human-extraterrestrial interaction has not yet been achieved for two reasons. First, alien energy is much more powerful than that of humans, so it would require thousands of thousands of years for the human race to develop a technology able to …

Looking For Life, Conor C. Grubb

CAFE Symposium 2023

The topic of aliens is not just about conspiracy theories and tinfoil hats, through the years numerous respected scientists have weighed in and put thought into the topic. The Search for Extraterrestrial Intelligence (SETI) is closely tied to the Fermi Paradox and the Drake Equation. The Fermi Paradox considers why humans haven't already interacted with aliens if they exist, and the Drake Equation outlines potential variables that would influence the chances of humanity receiving radio contact from an alien civilization.

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 …

Milky Way Morphology, Laurence A. Marschall

Physics and Astronomy Faculty Publications

From our limited perspective—living on a planet that orbits one of several hundred billion stars inside the Milky Way—the detailed structure of our home galaxy is difficult to determine. It has long been recognized by astronomers as a typical spiral galaxy, one of countless flattened pinwheels of stars seen throughout the universe. By mapping the distances to more than 2,400 stars, scientists have now created, with unprecedented precision, a three-dimensional map that shows the Milky Way has a twisted shape. [excerpt]

The Limited Reign Of Saturn's Rings, Laurence A. Marschall

Physics and Astronomy Faculty Publications

Saturn’s rings—stretching tens of thousands of miles above its equator but no more than a few hundred yards thick—mark an ancient debris field of orbiting ice shards, the remains of a moon-sized object that strayed too close and was torn to pieces by Saturn’s intense gravitation. Astronomers have debated when the rings formed and how long they will stay in orbit. Recent observations from large, land-based telescopes and orbiting spacecraft reveal that Saturn’s rings are remarkably young and are dissipating at a rapid rate. [excerpt]

Catching Shadow Bands, Laurence A. Marschall

Physics and Astronomy Faculty Publications

Even though shadow bands are only visible for a few fleeting minutes, it is possible to catch them if you prepare in advance. Get a large piece of white cardboard or white-painted plywood to act as a screen--the bands are subtle and can be more easily seen against a clean, white surface. (excerpt)

Back Half Of The Year, Ian R. Clarke

Physics and Astronomy Faculty Publications

Here we are in the back half of 2016, and the days are getting shorter. We have, as of today, lost 18 minutes since the solstice on June 20, and the speed of that change is quickening. You may wonder why it is that we have our hottest weather after our longest day is behind us. The simple answer is that it takes time for land and water masses to warm up. That’s the reason that Sept. 21 is likely to be a lot warmer than March 21, even though they have the same amount of daylight. [excerpt]

Living In The Milky Way, Ian R. Clarke

Physics and Astronomy Faculty Publications

It’s finally here. Today, June 20 at 6:34 p.m., is the the summer solstice, also known as the first day of summer and, confusingly enough, midsummer’s eve. From a scientific perspective, it marks the moment the sun reaches its northernmost point in our sky. As a result of that position, it’s the shortest night and longest day if you live north of the equator. [excerpt]

The Parallelization And Optimization Of The N-Body Problem Using Openmp And Openmpi, Nicholas J. Carugati

Student Publications

The focus of this research is exploring the efficient ways we can implement the NBody problem. The N-Body problem, in the field of physics, is a problem in which predicts or simulates the movements of planets and how they interact with each other gravitationally. For this research, we are viewing if the simulation can execute efficiently by delegating the heavy computational work through different cores of a CPU. The approach that is being used to figure this out is by integrating the parallelization API OpenMP and the message-passing library OpenMPI into the code. Rather than all the code executing on …

Precise Mass And Radius Measurements For The Components Of The Bright Solar-Type Eclipsing Binary Star V1094 Tauri, P. F.L. Maxted, R. J. Hutcheon, G. Torres, C. H.S. Lacy, J. Southworth, B. Smalley, K. Pavlovski, Laurence A. Marschall, J. V. Clausen

Physics and Astronomy Faculty Publications

Context. V1094 Tau is a bright eclipsing binary star with an orbital period close to nine days that contains two stars similar to the Sun.

Aims. Our aim is to test models of Sun-like stars using precise and accurate mass and radius measurements for both stars in V1094 Tau.

Methods. We present new spectroscopy of V1094 Tau, which we use to estimate the effective temperatures of both stars and to refine their spectroscopic orbits. We also present new, high-quality photometry covering both eclipses of V1094 Tau in the Strömgren uvby system and in the Johnson V-band.

Results. The masses, …

Transit Timing Analysis In The Hat-P-32 System, M. Seeliger, D. P. Dimitrov, D. Kjurkchieva, M. Mallonn, M. Fernandez, M. Kitze, V. Casanova, G. Maciejewski, J. M. Ohlert, J. G. Schmidt, A. Pannicke, D. Puchalski, E. Gogus, T. Guver, S. Bilir, T. Ak, M. M. Hohle, T. O.B. Schmidt, R. Errmann, E.L.N. Jensen, D. H. Cohen, Laurence A. Marschall, G. Saral, I. Bernt, E. Derman, C. Galan, R. Neuhauser

Physics and Astronomy Faculty Publications

We present the results of 45 transit observations obtained for the transiting exoplanet HATP- 32b. The transits have been observed using several telescopes mainly throughout the YETI (Young Exoplanet Transit Initiative) network. In 25 cases, complete transit light curves with a timing precision better than 1.4 min have been obtained. These light curves have been used to refine the system properties, namely inclination i, planet-to-star radius ratio Rp/Rs, and the ratio between the semimajor axis and the stellar radius a/Rs. First analyses by Hartman et al. suggests the existence of a second planet in the system, thus we tried to …

A Possible Detection Of Occultation By A Proto-Planetary Clump In Gm Cephei, W. P. Chen, S. C.-L. Hu, R. Errmann, Ch. Adam, Laurence A. Marschall

Physics and Astronomy Faculty Publications

GM Cep in the young (~ 4 Myr) open cluster Trumpler 37 has been known to be an abrupt variable and to have a circumstellar disk with very active accretion. Our monitoring observations in 2009–2011 revealed the star to show sporadic ?are events, each with brightening of . 0.5 mag lasting for days. These brightening events, associated with a color change toward the blue, should originate from an increased accretion activity. Moreover, the star also underwent a brightness drop of ~ 1 mag lasting for about a month, during which the star became bluer when fainter. Such brightness drops seem …

Absolute Dimensions Of The G7+K7 Eclipsing Binary Star Im Virginis: Discrepancies With Stellar Evolution Models, Juan Carlos Morales, Guillermo Torres, Laurence A. Marschall, William C. Brehm

Physics and Astronomy Faculty Publications

We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined eclipsing binary IMVir, composed of a G7-type primary and a K7 secondary.With these observations, we derive accurate absolute masses and radii of M1 = 0.981 + 0.012M, M2 = 0.6644 + 0.0048M, R1 = 1.061 + 0.016R, and R2 = 0.681 + 0.013R for the primary and secondary, with relative errors under 2%. The effective temperatures are 5570 + 100 K and 4250 + 130 K, respectively. The significant difference in mass makes this a favorable case for comparison with stellar evolution theory.We find that …

Stargazing: Observatories At Gettysburg College, 1874-Present, Andrew A. Carlson

Hidden in Plain Sight Projects

Astronomy has long been a subject which has attracted the interest of man. Examples of early astronomers can be found in many ancient civilizations, including but not limited to, the Egyptians, the Chinese and the Greeks. As time passed the methods for interpreting the stars and theories that surrounded them changed concordant with the technology available. One of the largest breakthroughs in the world of astronomy was the invention of the telescope in the early seventeenth century. Often mis-attributed to Galileo (who was responsible for building the first reflecting telescope in 1688), the telescope was actually first designed by a …

An Astronomical Account: A History Of Hatter Planetarium From 1966-2006, Jonathan D. Neu

Hidden in Plain Sight Projects

When most individuals stare up at the vast dome of Hatter Planetarium, they often gaze upon the projected stars appearing on its surface, listening to an astronomical story told by one of its operators. However, there is a second story told by the planetarium itself. This story is the history of Hatter Planetarium, which spans five decades and includes the events in the lives of several individuals who have played a critical role in its existence at Gettysburg College. Its history has encompassed several phases of Gettysburg College traditions but is in danger of passing permanently and fixedly into the …

The Eclipsing Binary V1061 Cygni: Confronting Stellar Evolution Models For Active And Inactive Solar-Type Stars, Guillermo Torres, Claud H. Sandberg Lacy, Laurence A. Marschall, Holly A. Sheets, Jeff A. Mader

Physics and Astronomy Faculty Publications

We present spectroscopic and photometric observations of the chromospherically active (X-ray strong) eclipsing binary V1061 Cyg (P = 2.35 days) showing that it is in reality a hierarchical triple system. We combine these observations with Hipparcos intermediate data (abscissa residuals) to derive the outer orbit with a period of 15.8 yr. We determine accurate values for the masses, radii, and effective temperatures of the eclipsing binary components, as well as for the mass and temperature of the third star. For the primary we obtain M = 1.282 ± 0.015 M⊙, R = 1.615 ± 0.017 R⊙, Teff = 6180 ± …

Optical Photometry And Spectroscopy Of The Suspected "Cool Algol" Av Delphini: Determination Of The Physical Properties, Jeff A. Mader, Laurence A. Marschall, Guillermo Torres, Akbar H. Rizvi

Physics and Astronomy Faculty Publications

We present new spectroscopic and BVRI photometric observations of the double-lined eclipsing binary AV Del ( period = 3:85 days) conducted over six observing seasons. A detailed radial velocity and light-curve analysis of the optical data shows the system to be most likely semidetached, with the less massive and cooler star filling its Roche lobe. The system is probably a member of the rare class of ‘‘cool Algol’’ systems, which are distinguished from the ‘‘classical’’ Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the spectroscopic and photometric …

Planetary Transits Of The Trans-Atlantic Exoplanet Survey- Candidate Tres-1b, Aaron Price, Ron Bissinger, Gregory P. Laughlin, Bruce L. Gary, Tonny Vanmunster, Arne A. Henden, Donn Ray Starkey, Daniel H. Kaiser, Jon A. Holtzman, Laurence A. Marschall, Thomas Michalik, T. Wellington, Pertti Paakkonen, Zsolt Kereszty, Russ Durkee, Kent Richardson, Robin Leadbeater, Timothy P. Castellano

Physics and Astronomy Faculty Publications

The AAVSO compiled 10,560 CCD observations of the suspected exoplanet transit object TrES-1b covering seven complete transit windows, three windows of partial coverage, and coverage of baseline non-transit periods. Visual inspection of the light curves reveals the presence of slight humps at the egress points of some transits. A boot strap Monte Carlo simulation was applied to the data to confirm that the humps exist to a statistically significant degree. However, it does not rule out systemic effects which will be tested with campaigns in the 2005 observing season.

Optical Photometry And X-Ray Monitoring Of The "Cool Algol" Bd+05˚706: Determination Of The Physical Properties, Guillermo Torres, Jeff A. Mader, Laurence A. Marschall, Ralph Neuhauser, Alaine S. Duffy

Physics and Astronomy Faculty Publications

We present new photometric observations in the BVRI bands of the double-lined eclipsing binary BD +05706 conducted over three observing seasons, as well as new X-ray observations obtained with ROSAT covering a full orbital cycle (P = 18.9 days). A detailed light-curve analysis of the optical data shows the system to be semidetached, confirming indications from an earlier analysis by Torres et al. (published in 1998), with the less massive and cooler star filling its Roche lobe. The system is a member of the rare class of cool Algol systems, which are different from the ‘‘ classical ’’ Algol systems …

Radial Velocity Survey Of Members And Candidate Members Of The Tw Hydrae Association, Guillermo Torres, Eike W. Guenther, Laurence A. Marschall, Ralph Neuhauser, David W. Latham, Robert P. Stefanik

Physics and Astronomy Faculty Publications

We report spectroscopic observations of stars belonging to the young nearby group known as the TW Hydrae association, as well as of a number of potential members of the association identified in kinematic and X-ray surveys. Multiple radial velocity measurements were obtained for each object, several of which turn out to be multiple systems. Orbital solutions are presented for three double-lined binaries, one singlelined binary, and a double-lined triple system, all with short periods. Effective temperatures and projected rotational velocities are presented for each visible object. None of the candidate members of the association in our sample are confirmed as …

A Desktop Universe For The Introductory Astronomy Laboratory, Laurence A. Marschall, Glenn A. Snyder, Paul Richard Cooper

Physics and Astronomy Faculty Publications

What is a well-intentioned astronomy instructor to do? There is no argument that experience with the real world is desirable in any astronomy course, especially the introductory classes that fulfill the science distribution requirements at many colleges and universities. Though it is a simple matter to take students out of doors, show them the motions of the Sun, Moon, and stars, and have them squint for a few seconds at Saturn's rings through a telescope, these activities represent only a small portion of the subject matter of modern astronomy. It is simply not possible, given the constraints of time, weather, …

The Universe On A Desktop: Observational Astronomy Simulations In The Instructional Laboratory, Laurence A. Marschall

Physics and Astronomy Faculty Publications

Though the value of hands-on learning has long been recognised by educators, it is difficult to design laboratories in astronomy classes that present realistic astrophysical techniques to undergraduate students. Unlike most other sciences, astronomy is largely observational, not experimental, and making useful observations involves expensive equipment over time scales inconvenient for pedagogy. In recent years, however, astronomy has gone almost completely digital, and the advent of large on-line databases and fast personal computers has made it possible to realistically simulate the experience of research astrophysics in the laboratory. Since 1992, Project CLEA (Contemporary Laboratory Experiences in Astronomy) has been developing …

The Type Ia Supernova 1998bu In M96 And The Hubble Constant, Saurabh Jha, Peter M. Garnavich, Robert P. Kirshner, Peter Challis, Alicia M. Soderberg, Lucas M. Macri, John P. Huchra, Pauline Barmby, Elizabeth J. Barton, Perry Berlind, Warren R. Brown, Nelson Caldwell, Michael L. Calkins, Sheila J. Kannappan, Daniel M. Koranyi, Michael A. Pahre, Kenneth J. Rines, Krzysztof Z. Stanek, Robert P. Stefanik, Andrew H. Szentgyorgyi, Petri Vaisanen, Zhong Wang, Joseph M. Zajac, Adam G. Riess, Alexei V. Filippenko, Weidong Li, Maryam Modjaz, Richard R. Treffers, Carl W. Hergenrother, Eva K. Grebel, Patrick Seitzer, George H. Jacoby, Priscilla J. Benson, Akbar H. Rizvi '99, Laurence A. Marschall, Jeffrey D. Goldader, Matthew Beasley, William D. Vacca, Bruno Leibundgut, Jason Spyromilio, Brian P. Schmidt, Peter R. Wood

Physics and Astronomy Faculty Publications

We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29 spectra of SN 1998bu between UT 1998 May 11 and July 15. The well-sampled light curve indicates the supernova reached maximum light in B on UT 1998 May 19.3 (JD 2450952.8^0.8) with B\12.22^0.03 and V \11.88^0.02. Application of a revised version of the Multicolor Light Curve Shape (MLCS) method yields an extinction toward the supernova of AV\0.94^0.15 mag, and indicates the supernova was of average luminosity compared …

New Rotation Periods In The Pleiades: Interpreting Activity Indicators, Anita Krishnamurthi, D. M. Terndrup, M. H. Pinsonneault, K. Sellgren, John R. Stauffer, Rudolph Schild, D. E. Backman, K. B. Beisser, D. B. Dahari, Amil Dasgupta, J. T. Hagelgans, M. A. Seeds, Rajan Anand '98, Bentley D. Laaksonen '95, Laurence A. Marschall, T. Ramseyer

Physics and Astronomy Faculty Publications

We present results of photometric monitoring campaigns of G, K and M dwarfs in the Pleiades carried out in 1994, 1995 and 1996. We have determined rotation periods for 18 stars in this cluster. In this paper, we examine the validity of using observables such as X-ray activity and amplitude of photometric variations as indicators of angular momentum loss. We report the discovery of cool, slow rotators with high amplitudes of variation. This contradicts previous conclusions about the use of amplitudes as an alternate diagnostic of the saturation of angular momentum loss. We show that the X-ray data can be …

The Eclipsing Double-Lined Spectroscopic Binary System V505 Persei, Laurence A. Marschall, Robert P. Stefanik, Claud H. Lacy, Guillermo Torres, David B. Williams, Franz Agerer

Physics and Astronomy Faculty Publications

The recently-discovered eclipsing double-lined spectroscopic binary V505 Persei (SAO 23229) consists of two nearly identical F5 main sequence stars in a 4.2 day orbit. We have obtained both spectroscopic and photometric observations of the binary that densely sample the complete cycle of radial velocity and light variations. These observations have been used to determine the elements of the orbit, to determine individual masses of the stars in the system to a precision of better than 1%, and to estimate an age for the system. The derived properties agree well with current stellar structure models and provide fundamental data for tests …

Bringing The Moon Into The Classroom, Laurence A. Marschall

Physics and Astronomy Faculty Publications

Understanding the phases of the Moon is a perennial stumbling block in introductory astronomy classes. In the film, "A Private Universe," for instance, both Harvard graduates and gifted high-school students display serious misconceptions about the Moon's phases, believing, among other things, that the Earth's shadow on the Moon is the cause of it all. Part of the problem may stem from textbook illustrations that show a view of the Moon in orbit around the Earth with the Sun of to one side. Students have trouble converting mentally from this "God's eye" perspective into the "geocentric" perspective we experience as observers …

Rotational Periods And Starspot Activity Of Young Solar-Type Dwarfs In The Open Cluster Ic 4665, S. Allain, C. Prosser, Laurence A. Marschall, Bentley D. Laaksonen

Physics and Astronomy Faculty Publications

We present the results of a V-band photometric monitoring survey of 15 late-type dwarfs in the young open cluster IC 4665. Low-amplitude periodic light variations are found for 8 stars and ascribed to the modulation by starspots that cover typically a few percent of the stellar disk. Periods range from 0.6 to 3.7d, translating to equatorial velocities between 13 and 93 km.s-1. That no period longer than 4d was detected suggests a relative paucity of extremely slow rotators (Veq << 10 km.s-1) among late-type dwarfs in IC 4665. The fractional number of slow rotators in IC 4665 is similar to that of Alpha Per cluster, suggesting that IC 4665 is close in age to Alpha Per (~50 Myr).

Ubvri Photometry Of The Type Ia Sn 1994d In Ngc 4526, Michael W. Richmond, Richard R. Treffers, Alexei V. Filippenko, Schuyler D. Van Dyk, Young Paik, Chien Peng, Laurence A. Marschall, Bentley D. Laaksonen, Bruce Macintosh, Ian S. Mclean

Physics and Astronomy Faculty Publications

We present optical photometry for the type Ia SN 1994D in NGC 4526 from 1994 March 7 to June 4 starting 13 days before B-band maximum. The light curves of this SN resemble closely those of the "normal" type Ia events SNe 1989B and 1980N, differing only in a slightly faster decline after maximum in VRI. The optical absolute magnitudes of SN 1994D, however, are significantly brighter than those of its near twins, and brighter than those predicted by Phillips' [ApJ, 413, L105 (1993)] relationship between decline rate and luminosity. Our small amount of IR photometry of SN 1994D …

Rotation Periods Of Open Cluster Stars, Iii, Charles F. Prosser, Matthew D. Shetrone, Amil Dasgupta, Dana E. Backman, Bentley D. Laaksonen, Shawn W. Baker, Laurence A. Marschall, Barbara A. Whitney, Konrad Kuuken, John R. Stauffer

Physics and Astronomy Faculty Publications

We present the results from a photometric monitoring program of 15 open cluster stars and one weak-lined T Tauri star during late 1993/early 1994. Several slow rotators which are members of the Alpha Persei, Pleiades, and Hyades open clusters have been monitored and period estimates derived. Using all available Pleiades stars with photometric periods together with current X-ray flux measurements, we illustrate the X-ray activity/rotation relation among Pleiades late-G/K dwarfs. The data show a clear break in the rotation-activity relation around P~6-7 days-in general accordance with previous results using more heterogeneous samples of G/K stars.