干旱区生态环境知识资源中心(Arid): Evolution of atmospheric escape in close-in giant planets and their associated Ly alpha and H alpha transit predictions

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DOI	10.1093/mnras/stz2842
	Evolution of atmospheric escape in close-in giant planets and their associated Ly alpha and H alpha transit predictions
	Allan, A.; Vidotto, A. A.
通讯作者	Allan, A.
来源期刊	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
ISSN	0035-8711
EISSN	1365-2966
出版年	2019
卷号	490 期号:3 页码:3760-3771
英文摘要	Strong atmospheric escape has been detected in several close-in exoplanets. As these planets consistmostly of hydrogen, observations in hydrogen lines, such as Ly alpha and H alpha, are powerful diagnostics of escape. Here, we simulate the evolution of atmospheric escape of close-in giant planets and calculate their associated Ly alpha and H alpha transits. We use a 1D hydrodynamic escape model to compute physical properties of the atmosphere and a ray tracing technique to simulate spectroscopic transits. We consider giant (0.3 and 1M(jup)) planets orbiting a solar-like star at 0.045 au, evolving from 10 to 5000 Myr. We find that younger giants show higher rates of escape, owing to a favourable combination of higher irradiation fluxes and weaker gravities. Less massive planets show higher escape rates (10(10)-10(13) g s(-1)) than those more massive (10(9)-10(12) g s(-1)) over their evolution. We estimate that the 1-Mjup planet would lose at most 1 per cent of its initial mass due to escape, while the 0.3-M-jup planet, could lose up to 20 per cent. This supports the idea that the Neptunian desert has been formed due to significant mass-loss in low-gravity planets. At younger ages, we find that the mid-transit Ly alpha line is saturated at line centre, while H alpha exhibits transit depths of at most 3-4 per cent in excess of their geometric transit. While at older ages, Ly alpha absorption is still significant (and possibly saturated for the lower mass planet), the H alpha absorption nearly disappears. This is because the extended atmosphere of neutral hydrogen becomes predominantly in the ground state after similar to 1.2Gyr.
英文关键词	hydrodynamics methods: numerical planets and satellites: atmospheres planets and satellites: gaseous planets
类型	Article
语种	英语
国家	Ireland
开放获取类型	Green Submitted, Bronze
收录类别	SCI-E
WOS记录号	WOS:000503993100050
WOS关键词	RADIATION PRESSURE ; STELLAR ; WINDS ; TIME ; EMISSION ; DYNAMICS ; STARS ; AGE
WOS类目	Astronomy & Astrophysics
WOS研究方向	Astronomy & Astrophysics
EI主题词	2019-12-01
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/311037
作者单位	Univ Dublin, Trinity Coll Dublin, Sch Phys, Dublin D02 PN40 2, Ireland
推荐引用方式 GB/T 7714	Allan, A.,Vidotto, A. A.. Evolution of atmospheric escape in close-in giant planets and their associated Ly alpha and H alpha transit predictions[J],2019,490(3):3760-3771.
APA	Allan, A.,&Vidotto, A. A..(2019).Evolution of atmospheric escape in close-in giant planets and their associated Ly alpha and H alpha transit predictions.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,490(3),3760-3771.
MLA	Allan, A.,et al."Evolution of atmospheric escape in close-in giant planets and their associated Ly alpha and H alpha transit predictions".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 490.3(2019):3760-3771.