Using the chromatic Rossiter-McLaughlin effect to probe the broadband signature in the optical transmission spectrum of HD 189733b

Transmission spectroscopy is a powerful technique for probing exoplanetary atmospheres. A successful ground-based observational method uses a differential technique based on high-dispersion spectroscopy, but that only preserves narrow features in transmission spectra. Here we use the chromatic Rossiter-McLaughlin (RM) effect to measure the Rayleigh-scattering slope in the transmission spectrum of HD 189733b with the aim to show that it can be effectively used to measure broadband transmission features. The amplitude of the RM effects depends on the effective size of the planet, and in the case of an atmospheric contribution therefore depends on the observed wavelength. We analysed archival HARPS data of three transits of HD 189733b, covering a wavelength range of 400 to 700 nm. We measured the slope in the transmission spectrum of HD 189733b at a $2.5\sigma$ significance. Assuming it is due to Rayleigh scattering and not caused by stellar activity, it would correspond to an atmospheric temperature, as set by the scale height, of $T = 2300 \pm 900 \mathrm{K}$, well in line with previously obtained results. This shows that ground-based high-dispersion spectral observations can be used to probe broad-band features in the transmission spectra of extrasolar planets, by using the chromatic RM effect. This method will be particularly interesting in conjunction with the new echelle spectrograph ESPRESSO, which currently is under construction for ESOs Very Large Telescope and will provide a gain in signal-to-noise ratio of about a factor 4 compared to HARPS. This will be of great value because of the limited and uncertain future of the Hubble Space Telescope and because the future James Webb Space Telescope will not cover this wavelength regime.Comment: 8 pages, 7 figures, accepted for publication on Astronomy and Astrophysic

Changing Employment Patterns in Nonmetropolitan America: Implications for Family Structure

During the past few decades, the industria/employment structure of rural America has changed dramatically. The major causes of these changes have been technological developments which have reduced the human labor needs in the natural resources industries of agriculture, forestry, fisheries, and mining. While employment in the natural resources industries has declined, the loss of these jobs has been offset by increased employment in the manufacturing and service industries. This paper explores the relationship between variations in the industrial structure of nonmetropolitan counties in the United States and several family structure variables. It was found that counties with larger proportions of their labor force employed in natural resources industries had fewer female-headed households, a larger proportion of children living in married-couple families, and higher fertility rates. In contrast, counties with high levels of employment in service and manufacturing industries had larger proportions of female-headed households, fewer children in married-couple households, and lower fertility rates. The implications of these findings are discussed

Economic Restructuring and Education in the Nonmetropolitan United States

Nonmetropolitan communities in the United States have historically depended on natural resources industries and manufacturing for their employment and sustenance. In recent decades, the number of jobs in these goods-producing industries has steadily declined, and this trend is likely to continue. The loss of goods producing jobs has been offset by increased employment in the service sector. A prominent concern resulting from this economic structure transformation is the impending mismatch in the education and skills of nonmetro workers and the education and skills needed to obtain high quality employment in the service sector. The data presented in this manuscript show that most nonmetro workers in the goods-producing industries have a high school education or less. Further, goods-producing workers with a high school degree or less, who are employed in the expanding service sector, earn considerably lower wages than can similarly educated workers in the contracting, goods-producing sector. On the other hand, the growth of service sector employment is resulting in increasing numbers of high quality jobs that generally require a college education. Unfortunately, the proportion of nonmetro workers with such education is relatively small. The implications of this mismatch are discussed