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Small-scale magnetic flux concentrations contribute significantly to the brightness variations of the Sun, yet observing them - particularly their magnetic field - near the solar limb remains challenging. Solar Orbiter offers an…

太阳与恒星天体物理 · 物理学 2026-02-11 K. Albert , J. Hirzberger , N. A. Krivova , X. Li , D. Calchetti , G. Valori , J. Sinjan , S. K. Solanki , A. Gandorfer , J. Woch , D. Orozco Suárez , S. Parenti

Tens of thousands of solar-like oscillating stars have been observed by space missions. Their photometric variability in the Fourier domain can be parameterized by a sum of two super-Lorentizian functions for granulation and a…

太阳与恒星天体物理 · 物理学 2022-02-15 Zhao Guo , Eric B. Ford , Dennis Stello , Jacob K. Luhn , Suvrath Mahadevan , Arvind F. Gupta , Jie Yu

We analyze space-based time series photometry of Sun-like stars, mostly in the Pleiades, but also field stars and the Sun itself. We focus on timescales between roughly 1 hour and 1 day. In the corresponding frequency band these stars…

太阳与恒星天体物理 · 物理学 2021-08-06 Timothy M. Brown , Rafael A. Garcia , Savita Mathur , Travis S. Metcalfe , Angela R. G. Santos

We study the nature of quiet-Sun oscillations using multi-wavelength observations from TRACE, Hinode, and SOHO. The aim is to investigate the existence of propagating waves in the solar chromosphere and the transition region via analyzing…

太阳与恒星天体物理 · 物理学 2012-09-27 G. R. Gupta , S. Subramanian , D. Banerjee , M. S. Madjarska , J. G. Doyle

Stellar surface magnetoconvection (granulation) creates asymmetries in the observed stellar absorption lines that can subsequently manifest themselves as spurious radial velocities shifts. In turn, this can then mask the Doppler-reflex…

地球与行星天体物理 · 物理学 2019-07-10 H. M. Cegla , C. A. Watson , S. Shelyag , M. Mathioudakis , S. Moutari

The contrast of granulation is an important quantity characterizing solar surface convection. We compare the intensity contrast at 630 nm, observed using the Spectro-Polarimeter (SP) aboard the Hinode satellite, with the 3D radiative MHD…

天体物理学 · 物理学 2009-11-13 S. Danilovic , A. Gandorfer , A. Lagg , M. Schüssler , S. K. Solanki , A. Vögler , Y. Katsukawa , S. Tsuneta

We present a detailed comparison between simulations and seeing-free observations that takes into account the crucial influence of instrumental image degradation. We use images of quiet Sun granulation taken in the blue, green and red…

太阳与恒星天体物理 · 物理学 2015-05-13 Sven Wedemeyer-Böhm , Luc Rouppe van der Voort

The characteristic of the solar acoustic spectrum is such that mode lifetimes get shorter and spatial leaks get closer in frequency as the degree of a mode increases for a given order. A direct consequence of this property is that…

天体物理学 · 物理学 2009-11-07 S. G. Korzennik , M. C. Rabello-Soares , J. Schou

Sunspots, faculae and the magnetic network contribute to solar irradiance variations. The contribution due to faculae and the network is of basic importance, but suffers from considerable uncertainty. We determine the contrasts of active…

天体物理学 · 物理学 2009-11-07 A. Ortiz , S. K. Solanki , V. Domingo , M. Fligge , B. Sanahuja

We assess the dependence of Earth's disk-integrated mid-infrared thermal emission spectrum on observation geometries and investigate which and how spectral features are impacted by seasonality on Earth. We compiled an exclusive dataset…

地球与行星天体物理 · 物理学 2023-04-04 Jean-Noel Mettler , Sascha P. Quanz , Ravit Helled , Stephanie L. Olson , Edward W. Schwieterman

It has been demonstrated that frequencies of f-modes can be used to estimate the solar radius to a good accuracy. These frequencies have been used to study temporal variations in the solar radius with conflicting results. The variation in…

天体物理学 · 物理学 2009-11-07 H. M. Antia

Gas convection is observed in the solar photosphere as the granulation, i.e., having highly time-dependent cellular patterns, consisting of numerous bright cells called granules and dark surrounding-channels called intergranular lanes. Many…

太阳与恒星天体物理 · 物理学 2020-03-04 T. Oba , Y. Iida , T. Shimizu

We have observed evidence for $p$-mode oscillations in the G0 IV star etaBoo (V = 2.68). This represents the first clear evidence of solar-like oscillations in a star other than the Sun. We used a new technique which measures fluctuations…

天体物理学 · 物理学 2009-10-22 Hans Kjeldsen , Timothy R. Bedding , Michael Viskum , Soeren Frandsen

The aim of this paper is to investigate whether there are any 11-yr or quasi-biennial solar cycle-related variations in solar rotational splitting frequencies of low-degree solar p modes. Although no 11-yr signals were observed, variations…

太阳与恒星天体物理 · 物理学 2015-06-04 Anne-Marie Broomhall , David Salabert , William J. Chaplin , Rafael A. Garcia , Yvonne Elsworth , Rachel Howe , Savita Mathur

The Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) instruments onboard the Solar Dynamics Observatory satellite produce Doppler velocity and continuum intensity at 6173 A as well as intensity maps at 1600…

太阳与恒星天体物理 · 物理学 2015-06-17 Sebastien Couvidat

The study of low-degree high-frequency waves in the Sun can provide new insight into the dynamics of the deeper layers of the Sun. Here, we present the analysis of the velocity observations of the Sun obtained from the Michelson and Doppler…

太阳与恒星天体物理 · 物理学 2010-03-12 Brajesh Kumar , Savita Mathur , R. A. Garcia , P. Venkatakrishnan

Adiabatic oscillation frequencies of stellar models, computed with the standard mixing-length formulation for convection, increasingly deviate with radial order from observations in solar-like stars. Standard solar models overestimate…

太阳与恒星天体物理 · 物理学 2016-11-15 G. Houdek , R. Trampedach , M. J. Aarslev , J. Christensen-Dalsgaard

We study temporal variations in the amplitudes and widths of high-degree acoustic modes in the quiet and active Sun by applying ring-diagram technique to the GONG+ and MDI Dopplergrams during the declining phase of cycle 23. The increase in…

太阳与恒星天体物理 · 物理学 2015-05-20 Olga Burtseva , S. C. Tripathy , R. Howe , K. Jain , F. Hill , R. Bogart , M. C. Rabello-Soares

We studied the radiative properties of small magnetic elements (active region faculae and the network) during the rising phase of solar cycle 23 from 1996 to 2001, determining their contrasts as a function of heliocentric angle, magnetogram…

天体物理学 · 物理学 2009-11-11 Ada Ortiz , Vicente Domingo , Blai Sanahuja

In the quiet regions on the solar surface, turbulent convective motions of granulation play an important role in creating small-scale magnetic structures, as well as in energy injection into the upper atmosphere. The turbulent nature of…

太阳与恒星天体物理 · 物理学 2020-03-04 Ryohtaroh T. Ishikawa , Yukio Katsukawa , Takayoshi Oba , Motoki Nakata , Kenichi Nagaoka , Tatsuya Kobayashi
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