PROTOPLANETARY DISK SHADOWING BY GAS INFALLING ONTO THE YOUNG STAR AK Sco
| Autor: | Ana I Gómez de Castro, Robert O. P. Loyd, Kevin France, Alexey Sytov, Dmitry Bisikalo |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
Photon Hydrogen 010308 nuclear & particles physics FOS: Physical sciences chemistry.chemical_element Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Alpha particle Astrophysics Protoplanetary disk 01 natural sciences Occultation Accretion (astrophysics) Stars Astrophysics - Solar and Stellar Astrophysics chemistry Space and Planetary Science 0103 physical sciences Binary star Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 818:L17 |
| ISSN: | 2041-8213 |
| DOI: | 10.3847/2041-8205/818/1/l17 |
| Popis: | Young solar-type stars grow through the accretion of material from the circumstellar disk during pre-main sequence (PMS) evolution. The ultraviolet radiation generated in this process plays a key role in the chemistry and evolution of young planetary disks. In particular, the hydrogen Lyman-alpha line (Lya) etches the disk surface by driving photoevaporative flows that control disk evolution. Using the Hubble Space Telescope, we have monitored the PMS binary star AK Sco during the periastron passage and have detected a drop of the H2 flux by up to 10% lasting 5.9 hours. We show that the decrease of the H2 flux can be produced by the occultation of the stellar Lya photons by a gas stream in free fall from 3 R*. Given the high optical depth of the Lya line, a very low gas column of NH > 5e17 cm-2 suffices to block the Lya radiation without producing noticeable effects in the rest of the stellar spectral tracers. ApJ Letters, accepted. January 25th, 2016 |
| Databáze: | OpenAIRE |
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