Issue |
A&A
Volume 688, August 2024
|
|
---|---|---|
Article Number | A61 | |
Number of page(s) | 11 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202450085 | |
Published online | 02 August 2024 |
A dusty magnetospheric stream explaining the light curves of the dipper objects: Finding a new inclination threshold to produce dippers
1
Departamento de Astronomía, Universidad de Guanajuato,
Callejón de Jalisco, S/N,
36240,
Guanajuato,
Guanajuato,
Mexico
e-mail: e.nagel@ugto.mx
2
Univ. Grenoble Alpes, CNRS, IPAG,
38000
Grenoble,
France
Received:
22
March
2024
Accepted:
18
June
2024
Context. The so-called “dippers” are young stellar objects that exhibit dimming episodes in their optical light curves. The common interpretation for the occurrence of these dips is that dusty regions periodically or quasi-periodically cross the line of sight toward the object.
Aims. We develop a model where we assume that these regions are located at the intersection of the magnetospheric stream with the disk. The stream is fed by gas and dust coming from the disk. As the material follows the magnetic field lines above the disk plane, it forms an opaque screen that partially blocks the stellar emission. The amount of extinction caused by the material crossing the line of sight depends on the abundance and location of the dust along the stream, which depends on the degree of dust evaporation due to the heating by the star.
Methods. We run hydrodynamical simulations of dusty accretion streams to produce synthetic dipper light curves for a sample of low-mass young stars still accreting from their disk according to evolutionary models. We compare the distribution of the light curve amplitudes between the synthetic sample and observed samples of dippers from various star-forming regions.
Results. Dust evaporation along the accretion column drives the distribution of photometric amplitudes. Our results suggest that most of the observed dippers correspond to systems seen at high inclination. However, dust survival within accretion columns may also produce dippers at lower inclination, down to about 45°. We find that the dust temperature arising from stellar irradiation should be increased by a factor 1.6 to find consistency between the fraction of dippers our model predicts in star-forming regions and the observed fraction of 20–30%.
Conclusions. Transient dust survival in accretion columns appear as an alternative (or complementary) mechanism to inner disk warp occultation in order to account for low-inclination dippers in star-forming regions.
Key words: circumstellar matter / stars: pre-main sequence
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.