M-band Imaging of the HR 8799 Planetary System Using an Innovative LOCI-based Background Subtraction Technique

Multi-wavelength observations/spectroscopy of exoplanetary atmospheres are the basis of the emerging exciting field of comparative exoplanetology. The HR 8799 planetary system is an ideal laboratory to study our current knowledge gap between massive field brown dwarfs and the cold 5-Gyr old Solar system planets. The HR 8799 planets have so far been imaged at J- to L-band, with only upper limits available at M-band. We present here deep high-contrast Keck II adaptive optics M-band observations that show the imaging detection of 3 of the 4 currently known HR 8799 planets. Such detections were made possible due to the development of an innovative LOCI-based background subtraction scheme that is 3 times more efficient than a classical median background subtraction for Keck II AO data, representing a gain in telescope time of up to a factor of 9. These M-band detections extend the broad band photometric coverage out to about 5 microns and provide access to the strong CO fundamental absorption band at 4.5microns. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. We also confirm that the best atmospheric fits are consistent with low surface gravity, dusty and non-equilibrium CO/CH4 chemistry models.Comment: 10 pages, 4 figures, 1 table, accepted in ApJ

Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere

Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging - spatially resolving the planet from its parent star - which enables high-resolution spectroscopy of self-luminous planets in Jovian-like orbits. Here, we present a spectrum with numerous, well-resolved, molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 AU from the star HR 8799. These data reveal the planet's chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygn ratio greater than the host star's, providing hints about the planet's formation.Comment: Accepted for publication in Science. Published online on March 14, 2013. 24 pages (main text and supplementary materials), 8 figures. Attachments to the supplementary material are available on Science websit

The International Deep Planet Survey II: The frequency of directly imaged giant exoplanets with stellar mass

Radial velocity and transit methods are effective for the study of short orbital period exoplanets but they hardly probe objects at large separations for which direct imaging can be used. We carried out the international deep planet survey of 292 young nearby stars to search for giant exoplanets and determine their frequency. We developed a pipeline for a uniform processing of all the data that we have recorded with NIRC2/Keck II, NIRI/Gemini North, NICI/Gemini South, and NACO/VLT for 14 years. The pipeline first applies cosmetic corrections and then reduces the speckle intensity to enhance the contrast in the images. The main result of the international deep planet survey is the discovery of the HR 8799 exoplanets. We also detected 59 visual multiple systems including 16 new binary stars and 2 new triple stellar systems, as well as 2,279 point-like sources. We used Monte Carlo simulations and the Bayesian theorem to determine that 1.05[+2.80-0.70]% of stars harbor at least one giant planet between 0.5 and 14M_J and between 20 and 300 AU. This result is obtained assuming uniform distributions of planet masses and semi-major axes. If we consider power law distributions as measured for close-in planets instead, the derived frequency is 2.30[+5.95-1.55]%, recalling the strong impact of assumptions on Monte Carlo output distributions. We also find no evidence that the derived frequency depends on the mass of the hosting star, whereas it does for close-in planets. The international deep planet survey provides a database of confirmed background sources that may be useful for other exoplanet direct imaging surveys. It also puts new constraints on the number of stars with at least one giant planet reducing by a factor of two the frequencies derived by almost all previous works.Comment: 83 pages, 13 figures, 15 Tables, accepted in A&

The Impact of Preparing Agriculture Faculty to Influence Student Critical Thinking Disposition

This study examined the effect of agriculture faculty training in and practice of methodologies to explicitly teach critical thinking skills related to course content and subsequent change in student critical thinking disposition. Twelve instructors in 14 agriculture courses underwent a year–long program of instruction in effective critical thinking development. Students completed the University of Florida–Engagement, Maturity, and Innovativeness assessment (UF–EMI) at the beginning and the end of the semester. Pair–wise comparisons showed significant increases in all three critical thinking dispositions (i.e., engagement, cognitive maturity, and innovativeness). In addition, a step–wise regression on the data gathered at the end of the semester showed that grade point average was positively related to all three critical thinking dispositions and being in one\u27s first year of college was negatively related to each dimension. The 300 course level was negatively related to innovativeness and engagement. Being in the second and third year of college were also negatively related to engagement. This study supports the notion that instructors can influence students’ critical thinking disposition within the limited time of a college semester

The Grizzly, March 21, 2002

Wynton Marsalis Brings Down the House at Ursinus • The True History of St. Patrick\u27s Day • Music Series set for Berman Museum • Ursinus Women\u27s History Month Dedicated to Late Professor • Meistersingers to Perform at Ursinus College • Berman Museum of Art to Feature Hans Moller Retrospective • SERV and Campus Safety to the Rescue • The New Fad Drug that Might be a Thinly Veiled Disaster • Girls Lacrosse Starts out Strong after a Productive Southern Swinghttps://digitalcommons.ursinus.edu/grizzlynews/1510/thumbnail.jp

The Grizzly, April 26, 2001

Watson Foundation Considers Ursinus for Membership • Dining Committee Addresses Rising Number of Student Complaints • Senior Student Young Named Ursinus Valedictorian • CAB, RHA, USGA, and Class Officer Elections Being Held • Opinions: Berg on Bush: First 100 Days of W a Comedy of Errors; Wismer: Taking a Turn for the Worse?; Awards Assembly Hot, Boring, Uninspired • Annual Student Art Exhibition now in Berman • Track: Men and Women Accelerate Toward Penn Relays • Baseball: Close to the .500 Mark, Third in Conference • Women\u27s LAX #1 Seed in Conference • Softball Squad Holding Steady in Third Place • Men\u27s and Women\u27s Tennis Look to end Season at CCC • Complications Lead to Delay in Field House Openinghttps://digitalcommons.ursinus.edu/grizzlynews/1489/thumbnail.jp

Moderate-resolution K-band Spectroscopy of Substellar Companion κ Andromedae b

We present moderate-resolution (R ~ 4000) K-band spectra of the "super-Jupiter," κ Andromedae b. The data were taken with the OSIRIS integral field spectrograph at Keck Observatory. The spectra reveal resolved molecular lines from H₂O and CO, and are compared to a custom PHOENIX atmosphere model grid appropriate for young planetary-mass objects. We fit the data using a Markov chain Monte Carlo forward-modeling method. Using a combination of our moderate-resolution spectrum and low-resolution, broadband data from the literature, we derive an effective temperature of T_(eff) = 1950–2150 K, a surface gravity of log g = 3.5–4.5, and a metallicity of [M/H] = −0.2–0.0. These values are consistent with previous estimates from atmospheric modeling and the currently favored young age of the system (<50 Myr). We derive a C/O ratio of 0.70_(-0.24)^(+0.09) for the source, broadly consistent with the solar C/O ratio. This, coupled with the slightly subsolar metallicity, implies a composition consistent with that of the host star, and is suggestive of formation by a rapid process. The subsolar metallicity of κ Andromedae b is also consistent with predictions of formation via gravitational instability. Further constraints on formation of the companion will require measurement of the C/O ratio of κ Andromedae A. We also measure the radial velocity of κ Andromedae b for the first time, with a value of −1.4 ± 0.9 km s⁻¹ relative to the host star. We find that the derived radial velocity is consistent with the estimated high eccentricity of κ Andromedae b