Differential rotation
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Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars Open
Can't keep hot sides hot and cold sides cold? On Earth, we're accustomed to cycles of day and night, which drive a complex thermal relationship between the ground and atmosphere. Some exoplanets very close to their stars aren't so lucky an…
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The Rossiter-McLaughlin effect reloaded: Probing the 3D spin-orbit geometry, differential stellar rotation, and the spatially-resolved stellar spectrum of star-planet systems Open
When a planet transits its host star, it blocks regions of the stellar surface from view; this causes a distortion of the spectral lines and a change in the line-of-sight (LOS) velocities, known as the Rossiter-McLaughlin (RM) effect. Sinc…
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Magnetic field formation in the Milky Way like disc galaxies of the Auriga project Open
The magnetic fields observed in the Milky Way and nearby galaxies appear to be in equipartition with the turbulent, thermal and cosmic ray energy densities, and hence are expected to be dynamically important. However, the origin of these s…
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The crucial role of surface magnetic fields for the solar dynamo Open
Sunspot cycle driven by linked fields Sunspots indicate magnetic flux emerging at the Sun's surface. Sunspots change over an 11-year time scale, which depends on the behavior of the probable magnetic dynamo within. Cameron et al. suggest t…
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Testing the recovery of stellar rotation signals from Kepler light curves using a blind hare-and-hounds exercise Open
We present the results of a blind exercise to test the recoverability of stellar rotation and differential rotation in Kepler light curves. The simulated light curves lasted 1000 d and included activity cycles, Sun-like butterfly patterns,…
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Rotational properties of hypermassive neutron stars from binary mergers Open
Determining the differential-rotation law of compact stellar objects produced\nin binary neutron stars mergers or core-collapse supernovae is an old problem\nin relativistic astrophysics. Addressing this problem is important because it\nim…
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Seismic evidence for a weak radial differential rotation in intermediate-mass core helium burning stars Open
The detection of mixed modes that are split by rotation in Kepler red giants\nhas made it possible to probe the internal rotation profiles of these stars,\nwhich brings new constraints on the transport of angular momentum in stars.\nMosser…
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On Differential Rotation and Overshooting in Solar-like Stars Open
We seek to characterize how the change of global rotation rate influences the overall dynamics and large-scale flows arising in the convective envelopes of stars covering stellar spectral types from early G to late K. We do so through nume…
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First 100 ms of a long-lived magnetized neutron star formed in a binary neutron star merger Open
The recent multimessenger observation of the short gamma-ray burst (SGRB) GRB\n170817A together with the gravitational wave (GW) event GW170817 provides\nevidence for the long-standing hypothesis associating SGRBs with binary neutron\nstar…
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Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO Open
We present optical and near-infrared high-contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total int…
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GRAND MINIMA AND EQUATORWARD PROPAGATION IN A CYCLING STELLAR CONVECTIVE DYNAMO Open
The 3-D magnetohydrodynamic (MHD) Anelastic Spherical Harmonic (ASH) code, using slope-limited diffusion, is employed to capture convective and dynamo processes achieved in a global-scale stellar convection simulation for a model solar-mas…
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Galactic rotation in <i>Gaia</i> DR1 Open
The spatial variations of the velocity field of local stars provide direct evidence of Galactic differential rotation. The local divergence, shear and vorticity of the velocity field – the traditional Oort constants – can be measured based…
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Differential crustal rotation and its control on giant ore clusters along the eastern margin of Tibet Open
Controls on the formation and distribution of mineralization in continental collisional settings remain unclear. However, our synthesis of diverse geophysical data sets from the eastern margin of Tibet revealed that differential crustal ro…
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Extended stellar systems in the solar neighborhood Open
We present a novel view on the morphology and dynamical state of ten prominent, nearby (≤500 pc), and young (∼30–300 Myr) open star clusters with Gaia DR2: α Per, Blanco 1, IC 2602, IC 2391, Messier 39, NGC 2451A, NGC 2516, NGC 2547, Plata…
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Optical, UV, and X-ray evidence for a 7-yr stellar cycle in Proxima Centauri Open
Stars of stellar type later than about M3.5 are believed to be fully\nconvective and therefore unable to support magnetic dynamos like the one that\nproduces the 11-year solar cycle. Because of their intrinsic faintness, very\nfew late M s…
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Turbulent Rotating Rayleigh–Bénard Convection Open
Rotation with thermally induced buoyancy governs many astrophysical and geophysical processes in the atmosphere, ocean, sun, and Earth's liquid-metal outer core. Rotating Rayleigh–Bénard convection (RRBC) is an experimental system that has…
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DETECTING DIFFERENTIAL ROTATION AND STARSPOT EVOLUTION ON THE M DWARF GJ 1243 WITH<i>KEPLER</i> Open
We present an analysis of the starspots on the active M4 dwarf GJ 1243, using 4 years of time series photometry from Kepler. A rapid P = 0.592596 ± 0.00021 days rotation period is measured due to the ∼2.2% starspot-induced flux modulations…
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Investigating the young AU Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass Open
We present a velocimetric and spectropolarimetric analysis of 27 observations of the 22-Myr M1 star AU Microscopii (AU Mic) collected with the high-resolution YJHK (0.98–2.35 μm) spectropolarimeter SPIRou from 2019 September 18 to November…
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Role of Interaction between Magnetic Rossby Waves and Tachocline Differential Rotation in Producing Solar Seasons Open
We present a nonlinear magnetohydrodynamic shallow-water model for the solar tachocline (MHD-SWT) that generates quasi-periodic tachocline nonlinear oscillations (TNOs) that can be identified with the recently discovered solar “seasons.” W…
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Activity trends in young solar-type stars Open
We study a sample of 21 young and active solar-type stars with spectral types\nranging from late F to mid K and characterize the behaviour of their activity.\nWe apply the continuous period search (CPS) time series analysis method on 16\nt…
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The hot Jupiter of the magnetically active weak-line T Tauri star V830 Tau Open
We report results of an extended spectropolarimetric and photometric monitoring of the weak-line T Tauri star V830 Tau and its recently detected newborn close-in giant planet. Our observations, carried out within the MaTYSSE (Magnetic Topo…
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Magnetic fields in non-convective regions of stars Open
We review the current state of knowledge of magnetic fields inside stars, concentrating on recent developments concerning magnetic fields in stably stratified (zones of) stars, leaving out convective dynamo theories and observations of con…
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Protostellar birth with ambipolar and ohmic diffusion Open
\n\t\t\t\tContext. The transport of angular momentum is fundamental during the formation of low-mass stars; too little removal and rotation ensures stellar densities are never reached, too much and the absence of rotation means no protopla…
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Extended main sequence turnoffs in open clusters as seen by Gaia – I. NGC 2818 and the role of stellar rotation Open
We present an analysis of the relatively low mass ($\\sim2400$~M$_{\\odot}$), $\\sim800$~Myr, Galactic open cluster, NGC~2818, using Gaia DR2 results combined with VLT/FLAMES spectroscopy. Using Gaia DR2 proper motions and parallax measure…
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Multiple populations in globular clusters: the distinct kinematic imprints of different formation scenarios Open
Several scenarios have been proposed to explain the presence of multiple stellar populations in globular clusters. Many of them invoke multiple generations of stars to explain the observed chemical abundance anomalies, but it has also been…
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Tracking the stellar longitudes of starspots in short-period Kepler binaries Open
We report on a new method for tracking the phases of the orbital modulations\nin very short-period, near-contact, and contact binary systems systems in order\nto follow starspots. We apply this technique to Kepler light curves for 414\nbin…
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Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. V. The Rapid Rotation of 47 Tuc Traced and Modeled in Three Dimensions<sup>*</sup> Open
High-precision proper motions of the globular cluster 47 Tuc have allowed us to measure for the first time the cluster rotation in the plane of the sky and the velocity anisotropy profile from the cluster core out to about 13′. These profi…
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The Global and Small-scale Magnetic Fields of Fully Convective, Rapidly Spinning M Dwarf Pair GJ65 A and B Open
The nearby M dwarf binary GJ65 AB, also known as BL Cet and UV Cet, is a unique benchmark for investigation of dynamo-driven activity of low-mass stars. Magnetic activity of GJ65 was repeatedly assessed by indirect means, such as studies o…
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MERIDIONAL FLOW IN THE SOLAR CONVECTION ZONE. II. HELIOSEISMIC INVERSIONS OF GONG DATA Open
Meridional flow is thought to play a very important role in the dynamics of the solar convection zone; however, because of its relatively small amplitude, precisely measuring it poses a significant challenge. Here we present a complete tim…
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Angular momentum transport efficiency in post-main sequence low-mass stars Open
Context. Using asteroseismic techniques, it has recently become possible to\nprobe the internal rotation profile of low-mass (~1.1-1.5 Msun) subgiant and\nred giant stars. Under the assumption of local angular momentum conservation,\nthe c…