Publication Abstracts

Bortolot 1972

Bortolot, V.J., Jr., 1972: The Interstellar Line Spectra of Zeta Ophiuchi and Zeta Persei and Their Relation to to the Short Wavelength Microwave Background Radiation. Ph.D. thesis. New York University.

Thirty-one high dispersion coudé spectrograms of ζ Oph (V = 2.7, MK-type O9.5V, bII = +23°) and seven of ζ Per (V = 2.83, MK-type B1Ib, bII = -17°) have been numerically synthesized to produce high resolution, low-noise spectra in the interval λλ3650-4350Å that yield more accurate data on atomic and molecular absorption in well-defined regions of the interstellar medium. The detection threshold is improved by as much as a factor of 5 over single plates. Several new interstellar lines have been discovered in the ζ Oph -15 km/sec cloud and the ζ Per +13 km/sec cloud. C13H+ λ4232 Å and KI λλ4043 and 4047 Å are seen in ζ Oph for the first time anywhere in the interstellar medium, and the previously observed Ca I λ4227 Å and Fe I λλ3720 and 3860 Å for the first time in both ζ Oph and ζ Per. Their equivalent widths range from 0.3 to 2 mÅ. Ca I λ4227 Å, with the strong Ca II H and K interstellar lines, yields the ionization equilibrium and hence the electron density. Reasonable limits on the photoionization rate computed from recently proposed galactic and stellar radiation fields yield ne = 0.16-0.55 cm-3 in the ζ Oph -15 km/sec clouds and ne = 0.044-0.14 cm-3 in the ζ Per +13 km/sec cloud. The neutral hydrogen density is estimated to be 50-700 cm-3 in the ζ Oph cloud and 10-80 cm-3 in ζ Per for reasonable assumptions of the cosmic ray ionization rate of hydrogen and the abundance of easily ionized trace elements. Sodium and potassium appear in the ζ Oph cloud approximately at their solar system abundances relative to hydrogen, but calcium, iron, and aluminum seem to be deficient by large factors — 2500, 300, amd >100, respectively. The abundances in ζ Per relative to sodium are similar, suggesting that most of the iron, aluminum, and perhaps other metals is bound up in the interstellar grains.

C13H+ λ4232 Å in ζ Oph yields a [C12]/[C13] ratio of 81 (+113, -16), consistent with terrestrial value 89. This suggests that C13-rich stars have not contributed much to the interstellar medium, at least in the vicinity of the sun, and that its composition has not changed much in thepast 5×109 years.

The CN, CH, and CH+ bands at λλ3875, 4300, and 4232 Å provide in all one precise measurement of the microwave background radiation brightness temperature and three upper limits at millimeter and submillimeter wavelengths. The CN excitation temperatures, corrected for local processes, yielf TB(λ2.64 mm) = 2.75±0.10°K in ζ Oph and 2.66±0.12°K in ζ Per. The upperlimits on the background radiation intensity in units of erg cm-2 sec-1 ster-1 Hz-1 are 0.72×10-14 at 1.32mm (CN), 1.66×10-14 at 0.56 mm (CH) and 3.75×10-14 at 0.36 mm (CH+). The CN excitation in six stars, including late B and early A giants, is found to be consistent with 2.8°K and consistent with a universal CN excitation mechanism.

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BibTeX Citation

@phdthesis{bo06100c,
  author={Bortolot, Jr., V. J.},
  title={The Interstellar Line Spectra of Zeta Ophiuchi and Zeta Persei and Their Relation to to the Short Wavelength Microwave Background Radiation},
  year={1972},
  school={New York University},
  address={New York, N.Y.},
}

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RIS Citation

TY  - THES
ID  - bo06100c
AU  - Bortolot, V. J., Jr.
PY  - 1972
BT  - The Interstellar Line Spectra of Zeta Ophiuchi and Zeta Persei and Their Relation to to the Short Wavelength Microwave Background Radiation
PB  - New York University
CY  - New York, N.Y.
ER  -

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