干旱区生态环境知识资源中心(Arid): The Hubble PanCET program: long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470

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DOI	10.1051/0004-6361/202140487
	The Hubble PanCET program: long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470
	Bourrier, V; dos Santos, L. A.; Sanz-Forcada, J.; Munoz, A. Garcia; Henry, G. W.; Lavvas, P.; Lecavelier, A.; Lopez-Morales, M.; Mikal-Evans, T.; Sing, D. K.; Wakeford, H. R.; Ehrenreich, D.
通讯作者	Bourrier, V (corresponding author), Univ Geneva, Observ Astronom, Chemin Pegasi 51b, CH-1290 Versoix, Switzerland.
来源期刊	ASTRONOMY & ASTROPHYSICS
ISSN	0004-6361
EISSN	1432-0746
出版年	2021
卷号	650
英文摘要	Neptune-size exoplanets seem particularly sensitive to atmospheric evaporation, making it essential to characterize the stellar high-energy radiation that drives this mechanism. This is particularly important with M dwarfs, which emit a large and variable fraction of their luminosity in the ultraviolet and can display strong flaring behavior. The warm Neptune GJ 3470b, hosted by an M2 dwarf, was found to harbor a giant exosphere of neutral hydrogen thanks to three transits observed with the Hubble Space Telescope Imaging Spectrograph (HST/STIS). Here we report on three additional transit observations from the Panchromatic Comparative Exoplanet Treasury program, obtained with the HST Cosmic Origin Spectrograph. These data confirm the absorption signature from GJ 3470b's exosphere in the stellar Lyman-alpha line and demonstrate its stability over time. No planetary signatures are detected in other stellar lines, setting a 3 sigma limit on GJ 3470b's far-ultraviolet (FUV) radius at 1.3 times its Roche lobe radius. We detect three flares from GJ 3470. They show different spectral energy distributions but peak consistently in the SiIII line, which traces intermediate-temperature layers in the transition region. These layers appear to play a particular role in GJ 3470's activity as emission lines that form at lower or higher temperatures than SiIII evolved differently over the long term. Based on the measured emission lines, we derive synthetic X-ray and extreme-ultraviolet (X+EUV, or XUV) spectra for the six observed quiescent phases, covering one year, as well as for the three flaring episodes. Our results suggest that most of GJ 3470's quiescent high-energy emission comes from the EUV domain, with flares amplifying the FUV emission more strongly. The neutral hydrogen photoionization lifetimes and mass loss derived for GJ 3470b show little variation over the epochs, in agreement with the stability of the exosphere. Simulations informed by our XUV spectra are required to understand the atmospheric structure and evolution of GJ 3470b and the role played by evaporation in the formation of the hot-Neptune desert.
英文关键词	techniques: spectroscopic planets and satellites: atmospheres planets and satellites: individual: GJ 3470 ultraviolet: stars stars: chromospheres
类型	Article
语种	英语
开放获取类型	Green Submitted
收录类别	SCI-E
WOS记录号	WOS:000661866400007
WOS关键词	EXTENDED UPPER-ATMOSPHERE ; X-RAY ; WARM NEPTUNE ; HD 189733B ; ULTRAVIOLET SPECTROSCOPY ; TRANSIT SPECTROSCOPY ; ESCAPING ATMOSPHERE ; HYDROGEN EXOSPHERE ; NEUTRAL HYDROGEN ; ATOMIC DATABASE
WOS类目	Astronomy & Astrophysics
WOS研究方向	Astronomy & Astrophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/349602
作者单位	[Bourrier, V; Ehrenreich, D.] Univ Geneva, Observ Astronom, Chemin Pegasi 51b, CH-1290 Versoix, Switzerland; [dos Santos, L. A.; Sanz-Forcada, J.] Ctr Astrobiol CSIC INTA, ESAC Campus,Pob 78, Madrid 28691, Spain; [Wakeford, H. R.] Univ Bristol, Sch Phys, HH Wills Phys Lab, Tyndall Ave, Bristol, Avon, England; [Sing, D. K.] Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA; [Sing, D. K.] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA; [Henry, G. W.] Tennessee State Univ, Ctr Excellence Informat Syst, Nashville, TN 37209 USA; [Munoz, A. Garcia] Univ Paris Saclay, Univ Paris, CNRS, CEA,AIM, F-91191 Gif Sur Yvette, France; [Mikal-Evans, T.] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA USA; [Lecavelier, A.] Sorbonne Univ, Inst dAstrophys Paris, CNRS, UMR 7095, 98Bis Bd Arago, F-75014 Paris, France; [Lavvas, P.] Univ Reims, Grp Spectrometrie Mol & Atmospher, Reims, France; [Lopez-Morales, M.] Harvard & Smithsonian, Ctr Astrophys, 60 Garden St, Cambridge, MA 01238 USA
推荐引用方式 GB/T 7714	Bourrier, V,dos Santos, L. A.,Sanz-Forcada, J.,et al. The Hubble PanCET program: long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470[J],2021,650.
APA	Bourrier, V.,dos Santos, L. A..,Sanz-Forcada, J..,Munoz, A. Garcia.,Henry, G. W..,...&Ehrenreich, D..(2021).The Hubble PanCET program: long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470.ASTRONOMY & ASTROPHYSICS,650.
MLA	Bourrier, V,et al."The Hubble PanCET program: long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470".ASTRONOMY & ASTROPHYSICS 650(2021).