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27 results on '"Elias, Jonathan H."'

1. TripleSpec 4: near-IR spectroscopy for the SOAR telescope

Author

Herter, Terry L., primary, Henderson, Chuck, additional, Bonati, Marco, additional, Wilson, John, additional, Allers, Katelyn, additional, David, Nicole, additional, Elias, Jonathan H., additional, James, David, additional, Piraces, Jose, additional, Points, Sean, additional, Probst, Ron, additional, Schlawin, Everett A., additional, Schurter, Patricio, additional, Tighe, Roberto, additional, and Warner, Michael, additional

Published
2020
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3. Five stellar occultations by Neptune - Further observations of ring arcs

Author

Nicholson, Philip D, Cooke, Maren L, Matthews, Keith, Elias, Jonathan H, and Gilmore, Gerard

Subjects
Lunar And Planetary Exploration
Abstract

Diffraction model fits to the light curves obtained during April 18, 1984 and August 20, 1985 stellar occultations that revealed incomplete rings, or 'arcs' around Neptune, are found to indicate arc radial widths of 8-26 km, and normal optical depths of 0.07-0.14. On the basis of the Neptune pole direction ascertained from Voyager navigation analyses, it is confirmed that the arc observed on August 20, 1985, together with the Hubbard et al. (1986) and Covault et al. (1986) arcs, seem to match the radius of the outermost ring found in Voyager images analyzed by Smith et al. (1989).

Published
1990
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12. IRAS and ground-based observations of star formation regions in the Magellanic clouds

Author

Elias, Jonathan H and Frogel, Jay A

Subjects
Astrophysics
Abstract

The Infrared Astronomy Satellite (IRAS) detected several hundred individual regions of star formation in the Large and Small Magellanic Clouds. Nearly two dozen of the brightest such sources were searched for from the ground at 10 microns; most of these were located and measured at wavelengths from 0.6 to 20 microns. Three principle results emerge from this study: First, the IRAS data show that star formation is considerably less active in the SMC than in the LMC, relative either to mass, luminosity, or H I content. The reduced activity in the SMC is consistent with the smaller amount of molecular material inferred from CO observations. Second, the sizes of the objects range from less than a few arcsecs (objects which look like extremely compact HII regions, with little or no extended radio, optical, or infrared emission) to some tens of arcsecs across (giant HII regions, of which the largest and brightest is 30 Doradus). Third, there are no obvious differences in the characteristics of the central portions of the LMC and SMC sources; all look like Galactic H II regions of similar luminosity.

Published
1987

19. Design of the Gemini near-infrared spectrometer

Author

Elias, Jonathan H., primary, Vukobratovich, Daniel, additional, Andrew, John R., additional, Cho, Myung K., additional, Cuberly, Randy W., additional, Don, Ken, additional, Gerzoff, Allen, additional, Harmer, Charles F. W., additional, Harris, D., additional, Heynssens, Julie B., additional, Hicks, J., additional, Kovacs, A., additional, Li, Cheng, additional, Liang, M., additional, Moon, Il-Kwon, additional, Pearson, Earl T., additional, Plum, G., additional, Roddier, Nicolas A., additional, Tvedt, Janet E., additional, Wolff, Richard J., additional, and Wong, Woon-Yin, additional

Published
1998
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21. Design of the Gemini near-infrared spectrometer.

Author

Elias, Jonathan H., Vukobratovich, Daniel, Andrew, John R., Cho, Myung K., Cuberly, Randy W., Don, Ken, Gerzoff, Allen, Harmer, Charles F. W., Harris, D., Heynssens, Julie B., Hicks, J., Kovacs, A., Li, Cheng, Liang, M., Moon, Il-Kwon, Pearson, Earl T., Plum, G., Roddier, Nicolas A., Tvedt, Janet E., and Wolff, Richard J.

Published
1998
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23. Cerro Tololo infrared spectrometer

Author

Gregory, Brooke, primary, DePoy, D. L., additional, Elias, Jonathan H., additional, Montane, Andres, additional, Perez, Gabriel, additional, Smith, Roger M., additional, and Webb, Gary L., additional

Published
1990
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24. Infrared studies of two dark clouds

Author

Elias, Jonathan H., Elias, Jonathan H., Elias, Jonathan H., and Elias, Jonathan H.

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The IC5146 dark cloud complex has been surveyed in the infrared in order to identify and study associated young stellar objects. Most of the objects detected in the survey appear to be field stars, predominantly late-type giants. Three young objects were detected in the survey: The BO star BD+4[…]3474, the Ae star BD+46[…]3471, and a previously unidentified object which appears to be a heavily obscured FU Ori star. The properties of the last two objects are examined in detail, and an attempt is made to produce reasonable models for them. It is suggested that FU Ori stars are binaries, and some consequences of this model are described. Photometry of the brighter stars in the IC5146 cluster has been used to establish a distance to the cluster of 900 ± 100 pc. A near-infrared survey has also been conducted of nearly 18 square degrees of the Ophiuchus dark cloud complex. Additional observations have been made of selected objects found in this survey and of the brighter objects found by Grasdalen et al. and by Vrba et al. in this region, in order to identify and study the young stars associated with the cloud. These observations show that very recent star formation has been largely restricted to a small region no more than a few parsecs in extent at the center of the dark cloud complex. Most of the young stars do not appear to be main sequence stars. At least three of these objects appear to be surrounded by infrared reflection nebulae. Many of the objects studied are background K and M giants which can be used to determine the near-infrared extinction due to the dark cloud.

Published
1978

25. The structure of Neptune's upper atmosphere: The stellar occultation of 24 May 1981

Author

French, Richard G., Elias, Jonathan H., Mink, Douglas J., and Elliot, J.L.

Abstract

Observations of the 24 May 1981 occultation of an uncatalogued star by Neptune made at the Cerro Tololo Inter-American Observatory have been analyzed to yield temperature profiles of Neptune's upper atmosphere for number densities near 5 × 1013cm−3. The mean temperatures at immersion (latitude −56°) and emersion (latitude −16°) obtained by numerical inversion were 140 ± 10°K and 154 ± 10°K, respectively. The immersion and emersion profiles are remarkably similar in overall shape, suggestive of global atmospheric layering. From the astrometry of the event, precise relative positions of Neptune and the occulted were obtained.

Published
1983
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26. Observed Bolometric Luminosities of Carbon Stars

Author

Iben, Icko, Jr., Renzini, Alvio, Frogel, Jay A., Cohen, Judith G., Persson, S. E., Elias, Jonathan H., Iben, Icko, Jr., Renzini, Alvio, Frogel, Jay A., Cohen, Judith G., Persson, S. E., and Elias, Jonathan H.

Abstract

To the best of our knowledge, most carbon stars are cool stars on their second ascent of the giant branch, i.e. the asymptotic giant branch. By some means they have mixed nuclear processed, carbon enriched material to their surfaces and probably have luminosities that are greater than those that mark the termination point of first time evolution up the giant branch, i.e. the location of the core helium flash. Observational and theoretical evidence for this picture may be found in Iben and Truran (1978), Renzini and Voli (1980), Scalo (1976), Richer, Olander and Westerlund (1979), and earlier references these authors cite.

Published
1981

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