Survey of cometary CO2, CO, and particulate emissions using the Spitzer Space Telescope: Smog check for comets

We surveyed 23 comets using the Infrared Array Camera on the Spitzer Space Telescope in wide filters centered at 3.6 and 4.5 microns. Emission in the 3.6 micron filter arises from sunlight scattered by dust grains; these images generally have a coma near the nucleus and a tail in the antisolar direction due to dust grains swept back by solar radiation pressure. The 4.5 micron filter contains the same dust grains, as well as strong emission lines from CO2 and CO gas; these show distinct morphologies, in which cases we infer they are dominated by gas. Based on the ratio of 4.5 to 3.6 micron brightness, we classify the survey comets as CO2+CO "rich" and "poor." This classification is correlated with previous classifications by A'Hearn based on carbon-chain molecule abundance, in the sense that comets classified as "depleted" in carbon-chain molecules are also "poor" in CO2+CO. The gas emission in the IRAC 4.5 micron images is characterized by a smooth morphology, typically a fan in the sunward hemisphere with a radial profile that varies approximately as the inverse of projected distance from the nucleus, as would apply for constant production and free expansion. There are very significant radial and azimuthal enhancements in many of the comets, and these are often distinct between the gas and dust, indicating that ejection of solid material may be driven either by H2O or CO2. Notable features in the images include the following. There is a prominent loop of gas emission from 103P/Hartley 2, possible due to an outburst of CO2 before the Spitzer image. Prominent, double jets are present in the image of 88P/Howell. A prominent single jet is evident for 3 comets. Spirals are apparent in 29P and C/2006 W3; we measure a rotation rate of 21 hr for the latter comet. Arcs (possibly parts of a spiral) are apparent in the images of 10P/Tempel 2, and 2P/Encke.Comment: accepted for publication in Icaru

A survey of debris trails from short-period comets

We observed 34 comets using the 24 micron camera on the Spitzer Space Telescope. Each image contains the nucleus and covers at least 10^6 km of each comet's orbit. Debris trails due to mm-sized or larger particles were found along the orbits of 27 comets; 4 comets had small-particle dust tails and a viewing geometry that made debris trails impossible to distinguish; and only 3 had no debris trail despite favorable observing conditions. There are now 30 Jupiter-family comets with known debris trails, of which 22 are reported in this paper for the first time. The detection rate is >80%, indicating that debris trails are a generic feature of short-period comets. By comparison to orbital calculations for particles of a range of sizes ejected over 2 yr prior to observation, we find that particles comprising 4 debris trails are typically mm-sized while the remainder of the debris trails require particles larger than this. The lower-limit masses of the debris trails are typically 10^11 g, and the median mass loss rate is 2 kg/s. The mass-loss rate in trail particles is comparable to that inferred from OH production rates and larger than that inferred from visible-light scattering in comae.Comment: accepted by Icarus; figures compressed for astro-p

Avoiding Constitutional Questions as a Three-Branch Problem

This article criticizes the cardinal rule of statutory construction known as the avoidance canon - that statutes must be interpreted to avoid raising serious constitutional questions - as failing to respect the proper constitutional roles of both Congress and the Executive. It argues that the avoidance canon in practice cannot be grounded in legislative supremacy, which is the common justification for it offered by the Supreme Court, because it assumes without foundation that Congress would always prefer not to come close to the constitutional line in enacting statutes. Instead, the avoidance canon creates pressure for courts to adopt statutory meanings that do not fairly reflect the legislative bargains struck in Congress. The article continues by arguing that the avoidance canon also impinges on the role of the Executive by disregarding its best judgment as to statutory meaning, arrived in the course of discharging the constitutional function of executing the law, because that judgment might be unconstitutional. Of course, if a statute passed by Congress, or a statutory interpretation proffered by the Executive, is actually - as opposed to possibly - unconstitutional, a court should not hesitate to say so in the course of deciding a case. On the whole, however, the article concludes that the separation of powers would be better served by the Supreme Court\u27s recognizing that there is as much danger of judicial usurpation from avoiding constitutional questions as deciding them

The Constitutional Dilemma of Litigation under the Independent Counsel System

The independent counsel system as established by the Ethics in Government Act of 1978 has put different components of the executive branch, such as the President and Department of Justice in the position of litigating against a special counsel. Litigation is not only a bad idea, it also gives rise to a serious constitutional dilemma. It either violates Article III because there is insufficient adversity to support litigation between the parties. Or it violates Article II, by preventing the President and his subordinates from controlling central functions of the executive branch, and places the independent counsel, an inferior officer, in a constitutionally superior position not only to the Attorney General but also to the President of the United States himself. Somewhat paradoxically, the system also intrudes on Article H values because it removes from the President the responsibility and accountability for how laws are executed. Either by directly violating Article I\u27s limitation of the judicial power to cases or controversies, or by impinging on the values and structure of Article H, the independent counsel system deeply violates the constitutional structure

Major accounting problems in corporate affiliation

Thesis (M.B.A.)--Boston University This item was digitized by the Internet Archive

Cannabis and Its Historical Role in America’s Intentional Segregation of Race

One of the more dramatic shifts in attitudes towards a particular trend or culture we have seen during the turn of the century is none other than attitudes towards marijuana. The Cannabis plant, commonly known as marijuana, has been illegal in the United States for a while now. In the past ten years, we have seen an influx of states and countries relaxing their attitudes towards marijuana, and it\u27s potential benefits. While this shift in attitude towards a relatively harmless drug is a step in the right direction, many are unaware of the sinister and racist history behind outlawing the plant in the first place that we still see today

Avoiding Constitutional Questions as a Three-Branch Problem

This article criticizes the cardinal rule of statutory construction known as the avoidance canon - that statutes must be interpreted to avoid raising serious constitutional questions - as failing to respect the proper constitutional roles of both Congress and the Executive. It argues that the avoidance canon in practice cannot be grounded in legislative supremacy, which is the common justification for it offered by the Supreme Court, because it assumes without foundation that Congress would always prefer not to come close to the constitutional line in enacting statutes. Instead, the avoidance canon creates pressure for courts to adopt statutory meanings that do not fairly reflect the legislative bargains struck in Congress. The article continues by arguing that the avoidance canon also impinges on the role of the Executive by disregarding its best judgment as to statutory meaning, arrived in the course of discharging the constitutional function of executing the law, because that judgment might be unconstitutional. Of course, if a statute passed by Congress, or a statutory interpretation proffered by the Executive, is actually - as opposed to possibly - unconstitutional, a court should not hesitate to say so in the course of deciding a case. On the whole, however, the article concludes that the separation of powers would be better served by the Supreme Court\u27s recognizing that there is as much danger of judicial usurpation from avoiding constitutional questions as deciding them

Avoiding Constitutional Questions as a Three-Branch Problem

This article criticizes the cardinal rule of statutory construction known as the avoidance canon - that statutes must be interpreted to avoid raising serious constitutional questions - as failing to respect the proper constitutional roles of both Congress and the Executive. It argues that the avoidance canon in practice cannot be grounded in legislative supremacy, which is the common justification for it offered by the Supreme Court, because it assumes without foundation that Congress would always prefer not to come close to the constitutional line in enacting statutes. Instead, the avoidance canon creates pressure for courts to adopt statutory meanings that do not fairly reflect the legislative bargains struck in Congress. The article continues by arguing that the avoidance canon also impinges on the role of the Executive by disregarding its best judgment as to statutory meaning, arrived in the course of discharging the constitutional function of executing the law, because that judgment might be unconstitutional. Of course, if a statute passed by Congress, or a statutory interpretation proffered by the Executive, is actually - as opposed to possibly - unconstitutional, a court should not hesitate to say so in the course of deciding a case. On the whole, however, the article concludes that the separation of powers would be better served by the Supreme Court\u27s recognizing that there is as much danger of judicial usurpation from avoiding constitutional questions as deciding them