Tauri Stage Research Articles

Infrared Excess and Dust Distribution around Stars.

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Infrared Excess and Dust Distribution around Stars. Huang, Su-Shu Abstract While Poveda (Bol. Obs. Tonantzktla Tacubaya 4 (26), t5, t965) and the present author (Publ. Astron. Soc. Pac*fic 77, 42, t965) have discussed the formation of planetary systems around stars in their T Tauri stage, it was the discovery of the infrared excess in these stars by Mendoza (Astrophys. J. 143, to to, 1966) that has renewed interest in this problem and led Low and Smith (Nature 212, 675, t966) to a similar suggestion. Models of dust distribution have been built by Stein (Astrophys. J. 145, tot, t966) and Low and Smith in order to account for observed infrared radiation. Both assume an optically thin dust distribution with a spherical symmetry with respect to the star. Theoretically we show that if this same assumption is made, an integral equation can be derived that relates the infrared spectrum with the variation of dust density in space. Moment relations can be obtained from the equation. The dust particles around stars could have already collapsed into a disk, following transfer of angular momentum from the star to the surrounding medium (Huang, Astrophys. J. 141, 985,1965). If so, we may conclude that a great part of the energy dissipated by the star at the T Tauri stage might be in the form of corpuscular radiation. Because of geometry the rotating disk around a central star does not receive a large portion of stellar electromagnetic energy. I t is difficult to account for the amount of infrared energy that is observed. Only high-energy corpuscles that do not necessarily follow a straight course can feed the required energy to the disk. Such a suggestion for the energy source is consistent with the spallation process for the production of light elements in the solar nebula, (Fowler, et al., Geophys. J. Roy. Astron. Soc. 6, 148,1962) and the flare activity of the pre-mainsequence stars (Schatzman, Ann. Astrophys. 25, 18,1952; Poveda, Nature 202,1319,1964). Publication: The Astronomical Journal Pub Date: September 1967 DOI: 10.1086/110546 Bibcode: 1967AJ.....72S.804H full text sources ADS | data products SIMBAD (1)

Production of the Rare Light Elements.

view Abstract Citations (24) References (39) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Production of the Rare Light Elements. Bashkin, S. ; Peaslee, D. C. Abstract The rare light isotopes H , He3, Li, Be, and B are discussed in terms of spallation reactions in stellar surfaces by locally produced high-energy particles This activity appears to be most intense during the ignition or T Tauri stage of a star. Present terrestrial abundances of Li, Be, and B are ascribed to solar activity of this magnitude during the period of formation of the solar system. The high terrestrial abundance of deuterium is associated with concentration effects in the primordial dust grains from which the plants accreted; the general abundance of deuterium should be much lower. It has not proved possible to decide whether the abundances of rare light isotopes observed in the sun reflect current production by solar flares or are the unburned remnants of an original stock; the large solar Be/Li ratio is anomalous on present considerations, and no explanation is offered. Publication: The Astrophysical Journal Pub Date: November 1961 DOI: 10.1086/147226 Bibcode: 1961ApJ...134..981B full text sources ADS |