المؤلفون: Davies, Claire L., Rich, Evan A., Harries, Tim J., Monnier, John D., Laws, Anna S. E., Andrews, Sean M., Bae, Jaehan, Wilner, David J., Anugu, Narsireddy, Ennis, Jacob, Gardner, Tyler, Kraus, Stefan, Labdon, Aaron, Le Bouquin, Jean-Baptiste, Lanthermann, Cyprien, Schaefer, Gail H., Setterholm, Benjamin R., ten Brummelaar, Theo

المساهمون: Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France

المصدر: ISSN: 0035-8711.

مصطلحات موضوعية: accretion, accretion discs, radiative transfer, techniques: high angular resolution, circumstellar matter, stars: formation, stars: individual: HD 145718, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics, [SDU]Sciences of the Universe [physics]

الوصف: International audience ; We present multi-instrument observations of the disc around the Herbig Ae star, HD 145718, employing geometric and Monte Carlo radiative transfer models to explore the disc orientation, the vertical and radial extent of the near-infrared (NIR) scattering surface, and the properties of the dust in the disc surface and sublimation rim. The disc appears inclined at 67-71°, with position angle, PA = -1.0 to 0.6°, consistent with previous estimates. The NIR scattering surface extends out to ${\sim}75\,$ au and we infer an aspect ratio, h scat (r)/r ~ 0.24 in J band; ~0.22 in H band. Our Gemini Planet Imager images and VLTI + CHARA NIR interferometry suggest that the disc surface layers are populated by grains ≳λ/2π in size, indicating these grains are aerodynamically supported against settling and/or the density of smaller grains is relatively low. We demonstrate that our geometric analysis provides a reasonable assessment of the height of the NIR scattering surface at the outer edge of the disc and, if the inclination can be independently constrained, has the potential to probe the flaring exponent of the scattering surface in similarly inclined (i ≳ 70°) discs. In re-evaluating HD 145718's stellar properties, we found that the object's dimming events - previously characterized as UX Or and dipper variability - are consistent with dust occultation by grains larger, on average, than found in the ISM. This occulting dust likely originates close to the inferred dust sublimation radius at $0.17\,$ au.

العلاقة: info:eu-repo/semantics/altIdentifier/arxiv/2201.06472; insu-03705355; https://insu.hal.science/insu-03705355Test; https://insu.hal.science/insu-03705355/documentTest; https://insu.hal.science/insu-03705355/file/stac149.pdfTest; ARXIV: 2201.06472; BIBCODE: 2022MNRAS.511.2434D

الإتاحة: https://doi.org/10.1093/mnras/stac149Test
https://insu.hal.science/insu-03705355Test
https://insu.hal.science/insu-03705355/documentTest
https://insu.hal.science/insu-03705355/file/stac149.pdfTest

المؤلفون: Davies, Claire L, Rich, Evan A, Harries, Tim J, Monnier, John D, Laws, Anna S E, Andrews, Sean M, Bae, Jaehan, Wilner, David J, Anugu, Narsireddy, Ennis, Jacob, Gardner, Tyler, Kraus, Stefan, Labdon, Aaron, le Bouquin, Jean-Baptiste, Lanthermann, Cyprien, Schaefer, Gail H, Setterholm, Benjamin R, ten Brummelaar, Theo, collaboration, G-LIGHTS

المصدر: Monthly Notices of the Royal Astronomical Society; Apr2022, Vol. 511 Issue 2, p2434-2452, 19p

مصطلحات موضوعية: SURFACE scattering, MINERAL dusts, RADIATIVE transfer, GEOMETRIC analysis, CIRCUMSTELLAR matter, STAR formation, DUST

مستخلص: We present multi-instrument observations of the disc around the Herbig Ae star, HD 145718, employing geometric and Monte Carlo radiative transfer models to explore the disc orientation, the vertical and radial extent of the near-infrared (NIR) scattering surface, and the properties of the dust in the disc surface and sublimation rim. The disc appears inclined at 67–71°, with position angle, PA = −1.0 to 0.6°, consistent with previous estimates. The NIR scattering surface extends out to |${\sim}75\,$| au and we infer an aspect ratio, h scat(r)/ r ∼ 0.24 in J band; ∼0.22 in H band. Our Gemini Planet Imager images and VLTI + CHARA NIR interferometry suggest that the disc surface layers are populated by grains ≳λ/2π in size, indicating these grains are aerodynamically supported against settling and/or the density of smaller grains is relatively low. We demonstrate that our geometric analysis provides a reasonable assessment of the height of the NIR scattering surface at the outer edge of the disc and, if the inclination can be independently constrained, has the potential to probe the flaring exponent of the scattering surface in similarly inclined (i ≳ 70°) discs. In re-evaluating HD 145718's stellar properties, we found that the object's dimming events – previously characterized as UX Or and dipper variability – are consistent with dust occultation by grains larger, on average, than found in the ISM. This occulting dust likely originates close to the inferred dust sublimation radius at |$0.17\,$| au. [ABSTRACT FROM AUTHOR]

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