Characterizing the AB Doradus Moving Group Via High Resolution Spectroscopy and Kinematic Traceback

We present a detailed analysis of 10 proposed F and G members of the nearby, young moving group AB Doradus (ABD). Our sample was obtained using the 2.7m telescope at the McDonald Observatory with the coude echelle spectrograph, achieving R $\sim$ 60,000 and S/N $\sim$ 200. We derive spectroscopic T$_{eff}$, log(g), [Fe/H], and microturbulance (v$_{t}$) using a bootstrap method of the TGVIT software resulting in typical errors of 33K in T$_{eff}$, 0.08 dex in log(g), 0.03 dex in [Fe/H], and 0.13 km s$^{-1}$ in v$_{t}$. Characterization of the ABD sample is performed in three ways: (1) Chemical homogeneity, (2) Kinematic Traceback, and (3) Isochrone fitting. We find the average metal abundance is [M/H] = -0.03 $\pm$ 0.06 with a traceback age of 125 Myrs. Our stars were fit to 3 different evolutionary models (Siess et al. 2000, Baraffe et al. 1998, and YREC) and we found the best match to our ABD sample is the YREC [M/H] = -0.1 model. In our sample of 10 stars, we identify 1 star which is a probable non-member, 3 enigmatic stars, and 6 stars with confirmed membership. We also present a list of chemically coherent stars from this study and the Barenfeld et al. (2013) study.Comment: 34 pages, 9 figures, 6 table

Characterizing the Nearest Young Moving Groups

Moving groups are associations of stars which originated from the same star forming region. These groups are typically young (\u3c 200 Myr) since they have not dissipated into the galactic field population. Over the last 15 years, roughly 10 such moving groups have been found with distances \u3c 150 pc (7 with distances \u3c 100 pc), each with a unique velocity and position. This work first investigates the likelihood to resolve star from two moving groups (AB Doradus and Beta Pictoris) using high spacial resolution optical interferrometry and found 5 AB Doradus stars and 1 Beta Pictoris star with declinations \u3e -30 could be spacially resolved. To more deeply characterize individual groups, we used the 2.7m telescope at the McDonald Observatory to observe 10 proposed AB Doradus stars and 5 proposed Octans-Near stars (3 probable members, 2 possible) with high resolution (R ~60,000) optical spectroscopy. Each group is characterized in three ways: (1) Chemical analysis to determine the homogeneity among members, (2) Kinematic traceback to determine the origin, and (3) Isochrone fitting to determine the age. We find the 8 stars in our AB Doradus sample are chemically homogeneous with [M/H] = -0.03 ± 0.06 dex, traceback to an age of 125 Myr, and the stars in this mass range are on the main sequence. The two deviants are a metal rich, potentially younger member and a metal poor, young star likely not associated with AB Doradus. In our Octans-Near sample, we find the 3 probable members have [M/H] = -0.06 ± 0.11, the stars do not trace back to a common origin, and the probable members are on the main sequence. In addition to these tests, we found that the probable members are slightly more lithium depleted than the Pleiades, implying an age between 125 and 200 Myr. Finally, we investigate systematic trends in fundamental stellar parameters from the use of different techniques. Preliminary results find differences in temperatures between interferrometric and spectroscopic techniques to be a function of temperature with a interferrometric temperatures being cooler by an average of 36 ± 115 K. We also calculated the chemical abundances as a function of condensation temperature for our moving group sample and predict 2 stars in AB Doradus could represent the initial star forming environment and discuss the implications for planet hosting stars in nearby moving groups. This updated characterization technique allows for a deeper understanding of the moving group environment. As future, high precision instruments emerge in astronomy (Jame Webb Space Telescope, GAIA, 30m class telescopes), moving groups are ideal targets since these associations will help us understand star forming regions, stellar evolution at young ages, constrain stellar evolutionary models, and identify planetary formation and evolution mechanisms

Evaluation of Disturbance Factors and Their Effect on Breeding Common Loons at Lake Umbagog National Wildlife Refuge, New Hampshire and Maine

Virtually any person exposed to American movies or television has likely heard the call of a common loon (Gavia immer). Its use as a sound prop has become ubiquitous in any scene related to the outdoors or the wilderness, even if the area filmed is in no way related to true loon habitat. The reason behind this is that the common loon and its haunting cries have come to symbolize the great outdoors. The sound of their call is meant to make the audience feel like the scene they are watching is in a remote area, far from the trappings of civilization, and, in our experience, it works. Hollywood has picked up on a sentiment held by many outdoor enthusiasts and is using it successfully. Unfortunately the southern range of the common loon is contracting and concern has been expressed over disturbance to breeding pairs by human activities, such as shoreline development, boating, and water-skiing, as well as possible contamination with lead, mercury, and other pollutants. If this alarming trend continues it may be that Hollywood movies will be the last place where a loon call can be heard in the United States. In the following chapters I will explore various threats to common loon populations. I will start in Chapter 1 with an evaluation of the potential effects of global warming on common loons within the North American breeding range. In Chapter 2 I review the available literature on wildlife disturbance and discuss some of the shortcomings and future research needs. I then go to a finer scale of study in Chapter 3 with a spatial analysis of disturbance factors and the effects on breeding common loons at Lake Umbagog National Wildlife Refuge. From there, in Chapter 4, I proceed to an analysis of specific behavioral responses exhibited by common loons in response to observed and experimentally imposed disturbance events. Finally, in Chapters 5 and 6, I briefly describe two natural disturbance events observed during our research, an immature bald eagle (Haliaeetus leucocephalus) predating a loon nest, and a loon nest defense of an aggressive American mink (Nevison vison)

Historical and contemporary perspectives on the sediments of Lake Rotorua

Lake Rotorua is probably the oldest continuously inundated lake in New Zealand, occupying a caldera formed by or closely associated with the eruption of the Mamaku ignimbrite and the collapse of the Rotorua caldera (Healy, 1975; Lowe and Green, 1991). The lake has undergone drastic changes in size and depth as a result of tectonics, volcanic activity and erosion. Since the Rotoehu eruption, (~60 kyr), the lake level has fluctuated between 120 m above present (280 m asl) and 10 m below present level. The modern lake covers an area of 79 km2 and has a mean depth of 10 m. Despite its long history of sedimentation, Lake Rotorua has an irregular bathymetry with features including faulted blocks, slumps, hydrothermal explosion craters, springs and large methane discharge pock marks

Weird inflects but OK : Making sense of morphological generation errors

We conduct a manual error analysis of the CoNLL-SIGMORPHON 2017 Shared Task on Morphological Reinflection. In this task, systems are given a word in citation form (e.g., hug) and asked to produce the corresponding inflected form (e.g., the simple past hugged). This design lets us analyze errors much like we might analyze children's production errors. We propose an error taxonomy and use it to annotate errors made by the top two systems across twelve languages. Many of the observed errors are related to inflectional patterns sensitive to inherent linguistic properties such as animacy or affect; many others are failures to predict truly unpredictable inflectional behaviors. We also find nearly one quarter of the residual "errors" reflect errors in the gold data. © 2019 Association for Computational Linguistics.Peer reviewe

Assessing estimators of snow leopard abundance

ABSTRACT The secretive nature of snow leopards (Uncia uncia) makes them difficult to monitor, yet conservation efforts require accurate and precise methods to estimate abundance. We assessed accuracy of Snow Leopard Information Management System (SLIMS) sign surveys by comparing them with 4 methods for estimating snow leopard abundance: predator:prey biomass ratios, capture-recapture density estimation, photo-capture rate, and individual identification through genetic analysis. We recorded snow leopard sign during standardized surveys in the SaryChat Zapovednik, the Jangart hunting reserve, and the Tomur Strictly Protected Area, in the Tien Shan Mountains of Kyrgyzstan and China. During June-December 2005, adjusted sign averaged 46.3 (SaryChat), 94.6 (Jangart), and 150.8 (Tomur) occurrences/km. We used counts of ibex (Capra ibex) and argali (Ovis ammon) to estimate available prey biomass and subsequent potential snow leopard densities of 8.7 (SaryChat), 1.0 (Jangart), and 1.1 (Tomur) snow leopards/100 km 2 . Photo capture-recapture density estimates were 0.15 (n ¼ 1 identified individual/1 photo), 0.87 (n ¼ 4/13), and 0.74 (n ¼ 5/6) individuals/100 km 2 in SaryChat, Jangart, and Tomur, respectively. Photo-capture rates (photos/100 trap-nights) were 0.09 (SaryChat), 0.93 (Jangart), and 2.37 (Tomur). Genetic analysis of snow leopard fecal samples provided minimum population sizes of 3 (SaryChat), 5 (Jangart), and 9 (Tomur) snow leopards. These results suggest SLIMS sign surveys may be affected by observer bias and environmental variance. However, when such bias and variation are accounted for, sign surveys indicate relative abundances similar to photo rates and genetic individual identification results. Density or abundance estimates based on capture-recapture or ungulate biomass did not agree with other indices of abundance. Confidence in estimated densities, or even detection of significant changes in abundance of snow leopard, will require more effort and better documentation

A Laboratory Study of C_3H^+ and the C_3H Radical in Three New Vibrationally Excited ^2Σ States Using a Pin-Hole Nozzle Discharge Source

Rotational lines of the positive molecular ion C_3H^+ and of the neutral C_3H radical in three new vibrationally excited states with ^2Σ symmetry have been detected in a supersonic molecular beam in the centimeter-wave band. The fundamental rotational line of the ion is quite weak, but is observed with similar intensity in a dc discharge through several different hydrocarbon gases when helium is the buffer gas. Under these conditions, the fractional abundance of C_3H^+ relative to C_3H is estimated to be of order 10^(−4), i.e., toward the lower end of the ratio (10^(−3)–10^(−4)) found for protonated ions using the same discharge nozzle. For each new ^2Σ state of the C_3H radical, spectroscopic constants, including those describing hydrogen hyperfine structure, have been determined to high precision. Lines of one ^2Σ state (B = 11271 MHz) are particularly intense in our molecular beam; for this state and a second one (B = 11306 MHz), millimeter-wave transitions have also been observed between 180 and 340 GHz using a long path dc glow absorption spectrometer. On the basis of intensity measurements with this spectrometer, the inferred rotation–vibration constant α, and theoretical calculations, the state with B = 11271 MHz is tentatively assigned to the ν_5 bending mode, predicted to lie ~300 cm^(−1) above ground

The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters

We validate the performance and accuracy of the current SEGUE (Sloan Extension for Galactic Understanding and Exploration) Stellar Parameter Pipeline (SSPP), which determines stellar atmospheric parameters (effective temperature, surface gravity, and metallicity) by comparing derived overall metallicities and radial velocities from selected likely members of three globular clusters (M 13, M 15, and M 2) and two open clusters (NGC 2420 and M 67) to the literature values. Spectroscopic and photometric data obtained during the course of the original Sloan Digital Sky Survey (SDSS-I) and its first extension (SDSS-II/SEGUE) are used to determine stellar radial velocities and atmospheric parameter estimates for stars in these clusters. Based on the scatter in the metallicities derived for the members of each cluster, we quantify the typical uncertainty of the SSPP values, sigma([Fe/H]) = 0.13 dex for stars in the range of 4500 K < Teff < 7500 K and 2.0 < log g < 5.0, at least over the metallicity interval spanned by the clusters studied (-2.3 < [Fe/H] < 0). The surface gravities and effective temperatures derived by the SSPP are also compared with those estimated from the comparison of the color-magnitude diagrams with stellar evolution models; we find satisfactory agreement. At present, the SSPP underestimates [Fe/H] for near-solar-metallicity stars, represented by members of M 67 in this study, by about 0.3 dex.Comment: 56 pages, 8 Tables, 15 figures, submitted to the Astronomical Journa