تقرير
The Variable Detection of Atmospheric Escape around the young, Hot Neptune AU Mic b
| العنوان: | The Variable Detection of Atmospheric Escape around the young, Hot Neptune AU Mic b |
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| المؤلفون: | Rockcliffe, Keighley E., Newton, Elisabeth R., Youngblood, Allison, Duvvuri, Girish M., Plavchan, Peter, Gao, Peter, Mann, Andrew W., Lowrance, Patrick J. |
| المصدر: | The Astronomical Journal, Volume 166, Number 2, 2023 |
| سنة النشر: | 2023 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | Photoevaporation is a potential explanation for several features within exoplanet demographics. Atmospheric escape observed in young Neptune-sized exoplanets can provide insight into and characterize which mechanisms drive this evolution and at what times they dominate. AU Mic b is one such exoplanet, slightly larger than Neptune (4.19 Earth radii). It closely orbits a 23 Myr pre-Main Sequence M dwarf with a period of 8.46 days. We obtained two visits of AU Mic b at Lyman-alpha with HST/STIS. One flare within the first HST visit is characterized and removed from our search for a planetary transit. We present a non-detection in our first visit followed by the detection of escaping neutral hydrogen ahead of the planet in our second visit. The outflow absorbed about 30% of the star's Lyman-alpha blue-wing 2.5 hours before the planet's white-light transit. We estimate the highest velocity escaping material has a column density of 10^13.96 cm^-2 and is moving 61.26 km/s away from the host star. AU Mic b's large high energy irradiation could photoionize its escaping neutral hydrogen in 44 minutes, rendering it temporarily unobservable. Our time-variable Lyman-alpha transit ahead of AU Mic b could also be explained by an intermediate stellar wind strength from AU Mic that shapes the escaping material into a leading tail. Future Lyman-alpha observations of this system will confirm and characterize the unique variable nature of its Lyman-alpha transit, which combined with modeling will tune the importance of stellar wind and photoionization. Comment: 24 pages, 11 figures |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.3847/1538-3881/ace536 |
| URL الوصول: | http://arxiv.org/abs/2307.15024 |
| رقم الأكسشن: | edsarx.2307.15024 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.3847/1538-3881/ace536 |
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