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The Kepler-11 system : Evolution of the stellar high-energy emission and initial planetary atmospheric mass fractions

Kubyshkina, D. ; Fossati, L. ; Mustill, A. J. LU ; Cubillos, P. E. ; Davies, M. B. LU ; Erkaev, N. V. ; Johnstone, C. P. ; Kislyakova, K. G. ; Lammer, H. and Lendl, M. , et al. (2019) In Astronomy and Astrophysics 632.
Abstract

The atmospheres of close-in planets are strongly influenced by mass loss driven by the high-energy (X-ray and extreme ultraviolet, EUV) irradiation of the host star, particularly during the early stages of evolution. We recently developed a framework to exploit this connection and enable us to recover the past evolution of the stellar high-energy emission from the present-day properties of its planets, if the latter retain some remnants of their primordial hydrogen-dominated atmospheres. Furthermore, the framework can also provide constraints on planetary initial atmospheric mass fractions. The constraints on the output parameters improve when more planets can be simultaneously analysed. This makes the Kepler-11 system, which hosts six... (More)

The atmospheres of close-in planets are strongly influenced by mass loss driven by the high-energy (X-ray and extreme ultraviolet, EUV) irradiation of the host star, particularly during the early stages of evolution. We recently developed a framework to exploit this connection and enable us to recover the past evolution of the stellar high-energy emission from the present-day properties of its planets, if the latter retain some remnants of their primordial hydrogen-dominated atmospheres. Furthermore, the framework can also provide constraints on planetary initial atmospheric mass fractions. The constraints on the output parameters improve when more planets can be simultaneously analysed. This makes the Kepler-11 system, which hosts six planets with bulk densities between 0.66 and 2.45 g cm-3, an ideal target. Our results indicate that the star has likely evolved as a slow rotator (slower than 85% of the stars with similar masses), corresponding to a high-energy emission at 150 Myr of between 1 and 10 times that of the current Sun. We also constrain the initial atmospheric mass fractions for the planets, obtaining a lower limit of 4.1% for planet c, a range of 3.7-5.3% for planet d, a range of 11.1-14% for planet e, a range of 1-15.6% for planet f, and a range of 4.7-8.7% for planet g assuming a disc dispersal time of 1 Myr. For planet b, the range remains poorly constrained. Our framework also suggests slightly higher masses for planets b, c, and f than have been suggested based on transit timing variation measurements. We coupled our results with published planet atmosphere accretion models to obtain a temperature (at 0.25 AU, the location of planet f) and dispersal time of the protoplanetary disc of 550 K and 1 Myr, although these results may be affected by inconsistencies in the adopted system parameters. This work shows that our framework is capable of constraining important properties of planet formation models.

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Contribution to journal
publication status
published
subject
keywords
Hydrodynamics, Planets and satellites: atmospheres, Planets and satellites: individual: Kepler-11 system, Planets and satellites: physical evolution
in
Astronomy and Astrophysics
volume
632
article number
A65
publisher
EDP Sciences
external identifiers
  • scopus:85103669834
ISSN
0004-6361
DOI
10.1051/0004-6361/201936581
language
English
LU publication?
yes
id
eee3da6e-4831-4f0c-9f3e-4f3d8742afd6
date added to LUP
2021-04-15 10:09:50
date last changed
2021-04-20 02:36:07
@article{eee3da6e-4831-4f0c-9f3e-4f3d8742afd6,
  abstract     = {<p>The atmospheres of close-in planets are strongly influenced by mass loss driven by the high-energy (X-ray and extreme ultraviolet, EUV) irradiation of the host star, particularly during the early stages of evolution. We recently developed a framework to exploit this connection and enable us to recover the past evolution of the stellar high-energy emission from the present-day properties of its planets, if the latter retain some remnants of their primordial hydrogen-dominated atmospheres. Furthermore, the framework can also provide constraints on planetary initial atmospheric mass fractions. The constraints on the output parameters improve when more planets can be simultaneously analysed. This makes the Kepler-11 system, which hosts six planets with bulk densities between 0.66 and 2.45 g cm-3, an ideal target. Our results indicate that the star has likely evolved as a slow rotator (slower than 85% of the stars with similar masses), corresponding to a high-energy emission at 150 Myr of between 1 and 10 times that of the current Sun. We also constrain the initial atmospheric mass fractions for the planets, obtaining a lower limit of 4.1% for planet c, a range of 3.7-5.3% for planet d, a range of 11.1-14% for planet e, a range of 1-15.6% for planet f, and a range of 4.7-8.7% for planet g assuming a disc dispersal time of 1 Myr. For planet b, the range remains poorly constrained. Our framework also suggests slightly higher masses for planets b, c, and f than have been suggested based on transit timing variation measurements. We coupled our results with published planet atmosphere accretion models to obtain a temperature (at 0.25 AU, the location of planet f) and dispersal time of the protoplanetary disc of 550 K and 1 Myr, although these results may be affected by inconsistencies in the adopted system parameters. This work shows that our framework is capable of constraining important properties of planet formation models. </p>},
  author       = {Kubyshkina, D. and Fossati, L. and Mustill, A. J. and Cubillos, P. E. and Davies, M. B. and Erkaev, N. V. and Johnstone, C. P. and Kislyakova, K. G. and Lammer, H. and Lendl, M. and Odert, P.},
  issn         = {0004-6361},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {The Kepler-11 system : Evolution of the stellar high-energy emission and initial planetary atmospheric mass fractions},
  url          = {http://dx.doi.org/10.1051/0004-6361/201936581},
  doi          = {10.1051/0004-6361/201936581},
  volume       = {632},
  year         = {2019},
}