scholarly journals EUV irradiation of exoplanet atmospheres occurs on Gyr time-scales

2020 ◽  
Vol 501 (1) ◽  
pp. L28-L32
Author(s):  
George W King ◽  
Peter J Wheatley
Keyword(s):  
Mass Loss ◽  
Time Scales ◽  
High Energy ◽  
Planetary Atmospheres ◽  
X Rays ◽  
X Ray ◽  
Atmospheric Escape ◽  
Euv Emission ◽  
Energy Emission ◽  
High Energy Emission

ABSTRACT Exoplanet atmospheres are known to be vulnerable to mass-loss through irradiation by stellar X-ray and extreme-ultraviolet (EUV) emission. We investigate how this high-energy irradiation varies with time by combining an empirical relation describing stellar X-ray emission with a second relation describing the ratio of solar X-ray to EUV emission. In contrast to assumptions commonly made when modelling atmospheric escape, we find that the decline in stellar EUV emission is much slower than in X-rays, and that the total EUV irradiation of planetary atmospheres is dominated by emission after the saturated phase of high-energy emission (which lasts around 100 Myr after the formation of the star). The EUV spectrum also becomes much softer during this slow decline. Furthermore, we find that the total combined X-ray and EUV emission of stars occurs mostly after the saturated phase. Our results suggest that models of atmospheric escape that focus on the saturated phase of high-energy emission are oversimplified, and when considering the evolution of planetary atmospheres it is necessary to follow EUV-driven escape on Gyr time-scales. This may make it more difficult to use stellar age to separate the effects of photoevaporation and core-powered mass-loss when considering the origin of the planet radius valley.

scholarly journals Slow motion pulsar wind nebulae

2021 ◽  
Vol 2103 (1) ◽  
pp. 012020
Author(s):  
K P Levenfish ◽  
G A Ponomaryov ◽  
A E Petrov ◽  
A M Bykov ◽  
A M Krassilchtchikov
Keyword(s):  
Time Scales ◽  
Relative Motion ◽  
Slow Motion ◽  
High Energy ◽  
Pulsar Wind Nebulae ◽  
Extra Time ◽  
X Ray ◽  
Energy Emission ◽  
Pulsar Wind ◽  
High Energy Emission

Abstract We show that even the slow (subsonic) motion of pulsar wind nebulae (PWNe) relative to an ambient matter has a significant impact on their observables. The motion changes the appearance of nebulae on X-ray images, comparing to what would be observed for a nebula at rest. Accounting for the relative motion is necessary to avoid misinterpretation of the structure of the nebulae when analyzing their X-ray morphology. The motion also introduces some extra time scales in variability of non-thermal high-energy emission of PWNe and allows to reproduce a number of their structures that are not explained by stationary nebula models.

X‐Rays from NGC 3256: High‐Energy Emission in Starburst Galaxies and Their Contribution to the Cosmic X‐Ray Background

1999 ◽  
Vol 526 (2) ◽  
pp. 649-664 ◽  
Author(s):  
Edward C. Moran ◽  
Matthew D. Lehnert ◽  
David J. Helfand
Keyword(s):  
High Energy ◽  
Starburst Galaxies ◽  
X Rays ◽  
X Ray ◽  
Energy Emission ◽  
X Ray Background ◽  
High Energy Emission

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

2019 ◽  
Vol 632 ◽  
pp. A65 ◽  
Author(s):  
D. Kubyshkina ◽  
L. Fossati ◽  
A. J. Mustill ◽  
P. E. Cubillos ◽  
M. B. Davies ◽  
...  
Keyword(s):  
Mass Loss ◽  
Extreme Ultraviolet ◽  
High Energy ◽  
X Ray ◽  
System Parameters ◽  
The Past ◽  
Energy Emission ◽  
Mass Fractions ◽  
High Energy Emission ◽  
Atmospheric Mass

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.

scholarly journals A New Chapter in Hard X-rays of the M87 AGN

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 9
Author(s):  
Ka-Wah Wong ◽  
Rodrigo S. Nemmen ◽  
Jimmy A. Irwin ◽  
Dacheng Lin
Keyword(s):  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Accretion Flow ◽  
Relativistic Jet ◽  
Very High Energy ◽  
Γ Ray ◽  
High Energy Emission ◽  
First Time ◽  
Very High

The nearby M87 hosts an exceptional relativistic jet. It has been regularly monitored in radio to TeV bands, but little has been done in hard X-rays ≳10 keV. For the first time, we have successfully detected hard X-rays up to 40 keV from its X-ray core with joint Chandra and NuSTAR observations, providing important insights to the X-ray origins: from the unresolved jet or the accretion flow. We found that the hard X-ray emission is significantly lower than that predicted by synchrotron self-Compton models introduced to explain very-high-energy γ -ray emission above a GeV. We discuss recent models to understand these high energy emission processes.

scholarly journals ON THE INTERACTION OF JETS WITH STELLAR WINDS IN MASSIVE X–RAY BINARIES

2010 ◽  
Vol 19 (06) ◽  
pp. 791-796
Author(s):  
MANEL PERUCHO ◽  
VALENTÍ BOSCH-RAMON ◽  
DMITRY KHANGULYAN
Keyword(s):  
Stellar Wind ◽  
Binary Star ◽  
Three Dimensional ◽  
High Energy ◽  
X Ray ◽  
Energy Emission ◽  
Injection Power ◽  
Radio Band ◽  
High Energy Emission ◽  
X Ray Binaries

We present the first three-dimensional simulations of the evolution of a microquasar jet inside the binary star system. The aim is to study the interaction of these jets with the stellar wind from a massive companion and the possible locations of high-energy emission sites. We have simulated two jets with different injection power in order to give a hint on the minimum power required for the jet to escape the system and become visible in larger scales. In the setup, we include a massive star wind filling the grid through which the jet evolves. We show that jets should have powers of the order of 1037 erg s-1 or more in order not to be destroyed by the stellar wind. The jet–wind interaction results in regions in which high-energy emission could be produced. These results imply the possible existence of a population of X–ray binaries undetected in the radio band due to jet disruption inside the region dominated by the stellar wind.

scholarly journals Historical Supernovae and Supernova Remnants

1996 ◽  
Vol 145 ◽  
pp. 323-331 ◽  
Author(s):  
Zhenru Wang
Keyword(s):  
Tang Dynasty ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
High Energy ◽  
X Rays ◽  
Supernovae And Supernova Remnants ◽  
X Ray ◽  
The Tang Dynasty ◽  
High Energy Emission ◽  
The Relationship

The oldest historical supernova (SN), recorded by ancient Chinese in 14th Century B.C. on pieces of tortoise shells or bones, is identified with the aid of modern space γ-ray observations. Hard X-rays with energy up to 20 keV were observed from IC 443 by the X-ray satellite Ginga. We infer from these observations the age of IC 443 is ∼ 1000 — 1400 yrs. The result supports the hypothesis that IC 443 is the remnant of the historical SN 837 that occurred during the Tang Dynasty. The association between the supernova remnant (SNR) CTB 80 and SN 1408 has been hotly debated for about ten years and is briefly reviewed and discussed here. A new picture is presented to explain this association. High energy emission from historical SNRs can persist in a multiphase interstellar medium (ISM). As a result, the study of the relationship between SNRs and ancient guest stars has gained new vitality.

scholarly journals PSR B0656+14: Combined Optical, X-ray & EUV Studies

2000 ◽  
Vol 177 ◽  
pp. 299-300
Author(s):  
Aaron Golden ◽  
Andy Shearer ◽  
Jerry Edelstein
Keyword(s):  
High Energy ◽  
Archival Data ◽  
Polar Cap ◽  
Optical Photometry ◽  
X Ray ◽  
Energy Emission ◽  
High Energy Emission

AbstractPSR B0656+14’s high energy emission is consistent with that of combined magnetospheric and thermal (surface & polar cap) emission. Uncertainties with the radio-derived distance and X-ray instrumentation sensitivities complicate a definitive thermal characterisation however. A re-analysis of combined ROSAT/EUVE archival data in conjunction with integrated & phase-resolved optical photometry is shown to constrain this characterisation.

scholarly journals Hydrogen Dominated Atmospheres on Terrestrial Mass Planets: Evidence, Origin and Evolution

2020 ◽  
Vol 216 (8) ◽  
Author(s):  
J. E. Owen ◽  
I. F. Shaikhislamov ◽  
H. Lammer ◽  
L. Fossati ◽  
M. L. Khodachenko
Keyword(s):  
Solar System ◽  
Large Population ◽  
High Energy ◽  
Terrestrial Planets ◽  
Important Process ◽  
X Ray ◽  
Origin And Evolution ◽  
Atmospheric Escape ◽  
Low Mass ◽  
High Energy Emission

AbstractThe discovery of thousands of highly irradiated, low-mass, exoplanets has led to the idea that atmospheric escape is an important process that can drive their evolution. Of particular interest is the inference from recent exoplanet detections that there is a large population of low mass planets possessing significant, hydrogen dominated atmospheres, even at masses as low as $\sim 2~\mbox{M}_{\oplus }$ ∼ 2 M ⊕ . The size of these hydrogen dominated atmospheres indicates the envelopes must have been accreted from the natal protoplanetary disc. This inference is in contradiction with the Solar System terrestrial planets, that did not reach their final masses before disc dispersal, and only accreted thin hydrogen dominated atmospheres. In this review, we discuss the evidence for hydrogen dominated atmospheres on terrestrial mass ($\lesssim 2~\mbox{M}_{\oplus }$ ≲ 2 M ⊕ ) planets. We then discuss the possible origins and evolution of these atmospheres with a focus on the role played by hydrodynamic atmospheric escape driven by the stellar high-energy emission (X-ray and EUV; XUV).

Sign in / Sign up

Export Citation Format

Share Document