The Detectability of Transit Depth Variations due to Exoplanetary Oblateness and Spin Precession

Knowledge of an exoplanet's oblateness and obliquity would give clues about its formation and internal structure. In principle, a light curve of a transiting planet bears information about the planet's shape, but previous work has shown that the oblateness-induced signal will be extremely difficult to detect. Here we investigate the potentially larger signals due to planetary spin precession. The most readily detectable effects are transit depth variations (T$\delta$V) in a sequence of light curves. For a planet as oblate as Jupiter or Saturn, the transit depth will undergo fractional variations of order 1%. The most promising systems are those with orbital periods of approximately 15--30 days, which is short enough for the precession period to be less than about 40 years, and long enough to avoid spin-down due to tidal friction. The detectability of the T$\delta$V signal would be enhanced by moons (which would decrease the precession period) or planetary rings (which would increase the amplitude). The Kepler mission should find several planets for which precession-induced T$\delta$V signals will be detectable. Due to modeling degeneracies, Kepler photometry would yield only a lower bound on oblateness. The degeneracy could be lifted by observing the oblateness-induced asymmetry in at least one transit light curve, or by making assumptions about the planetary interior.Comment: Accepted for publication in The Astrophysical Journa

Distribution of the Error in Estimated Numbers of Fixed Points of the Discrete Logarithm

Brizolis asked the question: does every prime p have a pair (g,h) such that h is a fixed point for the discrete logarithm with base g? The author and Pieter Moree, building on work of Zhang, Cobeli, and Zaharescu, gave heuristics for estimating the number of such pairs and proved bounds on the error in the estimates. These bounds are not descriptive of the true situation, however, and this paper is a first attempt to collect and analyze some data on the distribution of the actual error in the estimates.Comment: 8 pages, 3 figures, to appear in Communications in Computer Algebr

What Is A Number? Re-Thinking Derrida's Concept of Infinity

Iterability, the repetition which alters the idealization it reproduces, is the engine of deconstructive movement. The fact that all experience is transformative-dissimulative in its essence does not, however, mean that the momentum of change is the same for all situations. Derrida adapts Husserl's distinction between a bound and a free ideality to draw up a contrast between mechanical mathematical calculation, whose in-principle infinite enumerability is supposedly meaningless, empty of content, and therefore not in itself subject to alteration through contextual change, and idealities such as spoken or written language which are directly animated by a meaning-to-say and are thus immediately affected by context. Derrida associates the dangers of cultural stagnation, paralysis and irresponsibility with the emptiness of programmatic, mechanical, formulaic thinking. This paper endeavors to show that enumerative calculation is not context-independent in itself but is instead immediately infused with alteration, thereby making incoherent Derrida's claim to distinguish between a free and bound ideality. Along with the presumed formal basis of numeric infinitization, Derrida's non-dialectical distinction between forms of mechanical or programmatic thinking (the Same) and truly inventive experience (the absolute Other) loses its justification. In the place of a distinction between bound and free idealities is proposed a distinction between two poles of novelty; the first form of novel experience would be characterized by affectivites of unintelligibility , confusion and vacuity, and the second by affectivities of anticipatory continuity and intimacy

24 hours, Fall 2015

A poster promoting that the library is open 24 hours during the finals period

Exotic to Domestic

Undergraduate Graphic Desig

Language Learning and Interactive TV

The integration of engaging TV style content with the individualization and ‘intelligent’ content management offered by techniques from AI has the potential to provide learning environments that are both highly motivating and educationally sound. This paper describes why the area of language learning would be a particularly appropriate domain for interactive educational television to focus on. It also indicates some of the criteria to be fulfilled in order to provide optimal language learning conditions and how these might be satisfied using TV/Film content and techniques from AIED

Somewhere so over! the rainbow : the danger of safe-zones

When I see that acronym, I always think of the myriad other Js that could be substituted for Jesus—his answers being relentlessly predictable—and imagine potential outcomes given the specific individual. In truth, I never gave “what would Jesus do?” much thought until I moved to Kentucky, a place where many students sport rubber bracelets featuring those letters and take their affiliation with Christianity, as well as opposition to LGBT people, quite seriously. As a “J” myself, I answered that question in my first years as a junior faculty member with the response, “create a Safe Zone,” which, at the very least, did not seem un-Christian of me, though many disagree. I have spent a great deal of time in the past seven years contemplating Safe Zones— the national university project in the United States aimed at bettering the lives of LGBT students, faculty, and staff on campus—and thinking about the stickers emblazoned with their rainbow logo that decorate many office doors throughout my campus, and many others across this nation. I also think of Judy Garland—The Wizard of Oz “Dorothy” version—when I glimpse them and I’m immediately overcome by that cloyingly saccharine performance and naïve worldview. I like Judy immensely, as I do justice and equality for all, but only when she’s authentically largerthan-life, clearly overmedicated, and impishly brassy in black tights, pumps, short shorts, and a touch too much makeup. When I see her in those braids and that blue gingham dress speaking childishly, I feel I’m beginning to suffocate and that I must choose my words carefully. I respond similarly to the so-called Safe Zone I helped institute and now wish I could drop a house on.peer-reviewe