Are inner disc misalignments common? ALMA reveals an isotropic outer disc inclination distribution for young dipper stars
Autor: | Eric E. Mamajek, Eric Gaidos, Christina Hedges, Andrew W. Mann, Jonathan Williams, Grant M. Kennedy, I. Angelo, Aaron C. Rizzuto, Mark C. Wyatt, Marco Tazzari, T. L. Esplin, Adam L. Kraus, Gaspard Duchene, John M. Carpenter, Megan Ansdell |
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Rok vydání: | 2019 |
Předmět: |
Earth and Planetary Astrophysics (astro-ph.EP)
Physics biology 010308 nuclear & particles physics Dipper Isotropy FOS: Physical sciences Astronomy and Astrophysics Astrophysics biology.organism_classification 01 natural sciences Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Variable star Mathematics::Representation Theory 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Astrophysics - Earth and Planetary Astrophysics QB |
Zdroj: | Monthly Notices of the Royal Astronomical Society. 492:572-588 |
ISSN: | 1365-2966 0035-8711 1745-3933 |
Popis: | Dippers are a common class of young variable star exhibiting day-long dimmings with depths of up to several tens of percent. A standard explanation is that dippers host nearly edge-on (70 deg) protoplanetary discs that allow close-in (< 1 au) dust lifted slightly out of the midplane to partially occult the star. The identification of a face-on dipper disc and growing evidence of inner disc misalignments brings this scenario into question. Thus we uniformly (re)derive the inclinations of 24 dipper discs resolved with (sub-)mm interferometry from ALMA. We find that dipper disc inclinations are consistent with an isotropic distribution over 0-75 deg, above which the occurrence rate declines (likely an observational selection effect due to optically thick disc midplanes blocking their host stars). These findings indicate that the dipper phenomenon is unrelated to the outer (>10 au) disc resolved by ALMA and that inner disc misalignments may be common during the protoplanetary phase. More than one mechanism may contribute to the dipper phenomenon, including accretion-driven warps and "broken" discs caused by inclined (sub-)stellar or planetary companions. Accepted to MNRAS (19 pages, 7 figures, 2 tables) |
Databáze: | OpenAIRE |
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