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太阳风与火星相互作用是研究火星全球大气演化，深入理解火星全球气候环境演变的关键环节。研究表明，火星当前没有类似地球的全球偶极子磁场，太阳风直接与火星电离层相互作用形成全球性的感应磁层。如图1所示，太阳风携带行星际磁场与火星大气发生相互作用时，会产生火星感应磁层空腔结构。这一作用主要包括两个物理过程，一方面太阳风粒子受行星大气粒子的碰撞而减速，太阳风减速会使得行星际磁场在火星上游出现堆积和压缩。打个...
乐会军等-JGR-Planets：火星高层大气的南北不对称性（图）
火星高层大气 南北 不对称性
2023/1/16
火星高层大气（包括电离层和热层）是理解整个火星大气演化的重要基础，是火星大气逃逸的重要来源，因此成为火星探测的重要目标，国际上相关空间探测机构已对火星电离层进行了多次探测，如火星快车（Mars Express）、火星大气和挥发分演化探测（MAVEN），“天问一号”。高层大气的周日或逐日变化受低层大气各种波动过程向上传播的影响，这种扰动影响在短时间尺度上已有相关的事件研究，但长时间气候学尺度的耦合过...
Preface: Evolution of the early solar system: Presolar cosmochemical fingerprints and the formation of watery rocky planets
Presolar cosmochemical fingerprints the formation of watery rocky planets
2017/4/10
Recent developments in cosmochemistry of high-precision
and high spatial resolution isotope analyses, and of
high-performance computing techniques, have enabled
cosmochemists to gain vital insight ...
Evidence for enhanced chromospheric Ca II H & K emission in stars with close-in extrasolar planets
Planets and satellites magnetic fields Planet star interactions chromospheres
2012/2/23
The planet-star interaction is manifested in many ways. It was found out that a close-in exoplanet causes small but measurable variability in the cores of a few lines in the spectra of several stars w...
Gaps in Protoplanetary Disks as Signatures of Planets: I. Methodology and Validation
planet disk interactions protoplanetary disks planets and satellites detection radiative
2012/2/23
We examine the observational consequences of partial gaps being opened by planets in protoplanetary disks. We model the disk using a static alpha-disk model with detailed radiative transfer, parametri...
Habitability of Super-Earth Planets around Main-Sequence Stars including Red Giant Branch Evolution: Models based on the Integrated System Approach
Main-Sequence Stars including Red Giant Branch Evolution Models based Integrated System Approach
2011/10/20
In a previous study published in Astrobiology, we focused on the evolution of habitability of a 10 M_E super-Earth planet orbiting a star akin to the Sun. This study was based on a concept of planetar...
Rotating Stars and Revolving Planets: Bayesian Exploration of the Pulsating Sky
Time series Poisson point processes Harmonic analysis Periodograms Experimental design Astronomy Pulsars Extrasolar planets
2011/10/20
I describe ongoing work on development of Bayesian methods for exploring periodically varying phenomena in astronomy, addressing two classes of sources: pulsars, and extrasolar planets (exoplanets). F...
The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities
Planetary systems – Stars: activity – Stars: chromospheres – Line: profi les – Techniques: radial velocities – Techniques:spectroscopic
2011/10/17
Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic ac...
Shapes and gravitational fields of rotating two-layer Maclaurin ellipsoids: Application to planets and satellites
two-layer Maclaurin ellipsoids: Application to planets and satellites
2011/10/12
The exact solution for the shape and gravitational field of a rotating two-layer Maclaurin ellipsoid of revolution is compared with predictions of the theory of figures up to third order in the small ...
A natural formation scenario for misaligned and short-period eccentric extrasolar planets
open clusters and associations: general — planets and satellites: for- mation — planetary systems: protoplanetary disks — planetary systems: planet-disc interactions — planetary systems: planet-star interactions — physical data: hydrodynamics
2011/10/8
Recent discoveries of strongly misaligned transiting exoplanets pose a challenge to the established planet formation theory which assumes planetary systems to form and evolve in isolation. However, th...
Using Star Spots to Measure the Spin-orbit Alignment of Transiting Planets
Using Star Spots Measure Alignment Transiting Planets
2011/10/8
Spectroscopic follow-up of dozens of transiting planets has revealed the degree of alignment between the equators of stars and the orbits of the planets they host. Here we determine a method, applicab...
The HARPS search for southern extra-solar planets. XXX. Planetary systems around stars with solar-like magnetic cycles and short-term activity variation
stars: planetary systems – techniques: radial velocities – stars: activity – stars: individual: HD7199 – stars: individual
2011/9/30
We present the discovery of four new long-period planets within the HARPS high-precision sample: \object{HD137388}b ($M\sin{i}$ = 0.22 $M_J$), \object{HD204941}b ($M\sin{i}$ = 0.27 $M_J$), \object{HD7...
The HARPS search for southern extrasolar planets. XXV. Four new planets in orbit around the moderatly active dwarfs HD 63765, HD 104067, HD 125595, and HIP 70849
Techniques: radial velocities – Methods: data analysis – genetic algorithm Stars: individual:HD 104067 HD 125595 HIP 70849
2011/9/27
We report the detection of four new extrasolar planets in orbit around the moderately active stars HD 63765, HD 104067, HIP 70849, and HD 125595 with the HARPS Echelle spectrograph mounted on the ESO ...
A dynamo driven by zonal jets at the upper surface: applications to giant planets
giant planets upper surface
2011/9/1
We present a dynamo mechanism arising from the presence of barotropically unstable zonal jet currents in a spherical shell. The shear instability of the zonal flow develops in the form of a global Ros...
Scaling laws for convection and jet speeds in the giant planets
Scaling laws for convection jet speeds giant planets
2010/11/11
Three dimensional studies of convection in deep spherical shells have been used to test the hypothesis that the strong jet streams on Jupiter, Saturn, Uranus, and Neptune result from convection throug...