Trends in Silicates in the β Pictoris Disk
| Autor: | Lu, Cicero X., Chen, Christine H., Sargent, B. A., Watson, Dan M., Lisse, Carey M., Green, Joel D., Sitko, Michael L., Mittal, Tushar, Lebouteiller, Vianney, Sloan, G. C., Rebollido, Isabel, Hines, Dean C., Girard, Julien H., Werner, Michael W., Stapelfeldt, Karl R., Wu, Winston, Worthen, Kadin, Lu, Cicero, Chen, Christine, Watson, Dan, Lisse, Carey, Green, Joel, Sitko, Michael, Hines, Dean, Girard, Julien, Werner, Michael, Stapelfeldt, Karl |
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| Přispěvatelé: | Space Telescope Science Institute (STSci), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory, California Institute of Technology (JPL) |
| Rok vydání: | 2022 |
| Předmět: |
Earth and Planetary Astrophysics (astro-ph.EP)
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] Silicate grains FOS: Physical sciences Astronomy and Astrophysics Exozodiacal dust [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] Exoplanet formation [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA] Debris disks Astrophysics - Solar and Stellar Astrophysics Infrared astronomy Space and Planetary Science Planetary system formation Planetesimals Spectroscopy Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, 2022, 933 (1), pp.54. ⟨10.3847/1538-4357/ac70d1⟩ |
| ISSN: | 1538-4357 0004-637X |
| Popis: | While beta Pic is known to host silicates in ring-like structures, whether the properties of these silicate dust vary with stellocentric distance remains an open question. We re-analyze the beta Pictoris debris disk spectrum from the Spitzer Infrared Spectrograph (IRS) and a new IRTF/SpeX spectrum to investigate trends in Fe/Mg ratio, shape, and crystallinity in grains as a function of wavelength, a proxy for stellocentric distance. By analyzing a re-calibrated and re-extracted spectrum, we identify a new 18 micron forsterite emission feature and recover a 23 micron forsterite emission feature with a substantially larger line-to-continuum ratio than previously reported. We find that these prominent spectral features are primarily produced by small submicron-sized grains, which are continuously generated and replenished from planetesimal collisions in the disk and can elucidate their parent bodies' composition. We discover three trends about these small grains: as stellocentric distance increases, (1) small silicate grains become more crystalline (less amorphous), (2) they become more irregular in shape, and (3) for crystalline silicate grains, the Fe/Mg ratio decreases. Applying these trends to beta Pic's planetary architecture, we find that the dust population exterior to the orbits of beta Pic b and c differs substantially in crystallinity and shape. We also find a tentative 3-5 micron dust excess due to spatially unresolved hot dust emission close to the star. From our findings, we infer that the surfaces of large planetesimals are more Fe-rich and collisionally-processed closer to the star but more Fe-poor and primordial farther from the star. Comment: 19 pages, 12 figures, Accepted for Publication in ApJ |
| Databáze: | OpenAIRE |
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