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  • 1
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    A search for pre-main-sequence stars in high-latitude molecular clouds. 3: A survey of the Einstein database (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: In order to discern whether the high-latitude molecular clouds are regions of ongoing star formation, we have used X-ray emission as a tracer of youthful stars. The entire Einstein database yields 18 images which overlap 10 of the clouds mapped partially or completely in the CO (1-0) transition, providing a total of approximately 6 deg squared of overlap. Five previously unidentified X-ray sources were detected: one has an optical counterpart which is a pre-main-sequence (PMS) star, and two have normal main-sequence stellar counterparts, while the other two are probably extragalactic sources. The PMS star is located in a high Galactic latitude Lynds dark cloud, so this result is not too suprising. The translucent clouds, though, have yet to reveal any evidence of star formation.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 441; 1; p. 261-269
    Format: text
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  • 2
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    A search for T Tauri stars in high-latitude molecular clouds. 2: The IRAS Faint Source Survey catalog (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: We present a catalog of infrared point sources from the IRAS Faint Source Survey at Galactic latitudes the absolute magnitude of b is greater than or equal to 30 deg. The aim of this paper is to provide a list of possible star-forming sites at high Galactic latitudes in order to address the question of whether or not the translucent molecular clouds (which are most easily identified at high latitudes) are capable of star formation. The primary list of sources has 12, 25, 60, and 100 micron fluxes within the range typical of pre-main-sequence or T Tauri stars. A secondary list has the same range of 12, 25, and 60 micron fluxes, but only upper limits at 100 microns. A total of 127 candidates from the first category and 65 candidates from the second category are identified and their positions and infrared spectral characteristics tabulated. Although the colors and fluxes of these sources are typical of T Tauri or pre-main-sequence stars and YSOs, extragalactic sources and planetary nebulae sometimes have similar colors. These lists provide a starting point for optical spectroscopy or other techniques to positively identify these objects. We can determine an upper limit to the star forming efficiency of high-latitude molecular clouds assuming all the candidates in our sample are pre-main sequence stars of one solar mass. The upper limit of a few tenths of 1% is less than the star-forming efficiency of local dark cloud complexes such as the Taurus-Auriga or rho Ophiuchus clouds.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 96; 1; p. 159-173
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  • 3
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    CO(+) fluorescence in comets (1986)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: Calculations of the fluorescent equilibrium of the CO(+) molecule to determine the Swings and Greenstein effects as a function of heliocentric radial velocity have been carried out. The previously ignored Baldet-Johnson (B-A) bands were included in addition to the comet tail (A-X) and first negative (B-X) bands, thus allowing a determination of the absolute intensities of all bands. As with certain other molecules such as OH and CN, the Swings effect on individual lines is large enough that integrated band fluxes in the comet tail system also exhibit the Swings effect. The flux variations for velocities in the range - 50 to + 350 km/s have been calculated and may be used to map the acceleration of CO(+) ions into the tail, even with low dispersion spectra.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 302; 477-487
    Format: text
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