334 citations · 3.7k across the 43 of their papers we have counts for
28 papers · 1 filter
Possible detection of coronal mass ejections on late-type main-sequence stars in LAMOST medium-resolution spectra
Hong-peng Lu, Hui Tian, Li-yun Zhang +9
Context. Stellar coronal mass ejections (CMEs) are the primary driver of the exoplanetary space weather and they could affect the habitability of exoplanets. However, detections of…
Signatures of magnetic activity: On the relation between stellar properties and p-mode frequency variations
A. R. G. Santos, T. L. Campante, W. J. Chaplin +12
In the Sun, the properties of acoustic modes are sensitive to changes in the magnetic activity. In particular, mode frequencies are observed to increase with increasing activity le…
HAYDN -- High-precision AsteroseismologY of DeNse stellar fields (ESA Voyage 2050 White Paper)
Andrea Miglio, Leo Girardi, Frank Grundahl +29
In the last decade, the Kepler and CoRoT space-photometry missions have demonstrated the potential of asteroseismology as a novel, versatile and powerful tool to perform exquisite…
Christian Horrebow's Sunspot Observations -- II. Construction of a Record of Sunspot Positions
Christoffer Karoff, Carsten Sønderskov Jørgensen, V. Senthamizh Pavai +1
The number of spots on the surface of the Sun is one of the best tracers of solar variability we have. The sunspot number is not only known to change in phase with the 11-year sola…
Christian Horrebow's Sunspot Observations -- I. Life and Published Writings
Carsten Sønderskov Jørgensen, Christoffer Karoff, V. Senthamizh Pavai +1
Between 1761 and 1776, Christian Horrebow made regular observations of sunspots from Rundetaarn in Copenhagen. Based on these observations he writes in 1775 that "it appears that a…
Using Machine Learning Methods to Forecast If Solar Flares Will Be Associated with CMEs and SEPs
Fadil Inceoglu, Jacob H. Jeppesen, Peter Kongstad +3
Among the eruptive activity phenomena observed on the Sun, the most technology threatening ones are flares with associated coronal mass ejections (CMEs) and solar energetic particl…
The influence of metallicity on stellar differential rotation and magnetic activity
Christoffer Karoff, Travis S. Metcalfe, Angela R. G. Santos +20
Observations of Sun-like stars over the last half-century have improved our understanding of how magnetic dynamos, like that responsible for the 11-year solar cycle, change with ro…
Chromospheric emission of planet candidate systems - a way to identify false positives
Christoffer Karoff, Simon Albrecht, Alfio Bonanno +1
It has been hypothesized that the presence of closely orbiting giant planets is associated with enhanced chromospheric emission of their host stars. The main cause for such a relat…
Oscillation frequencies for 35 \Kepler solar-type planet-hosting stars using Bayesian techniques and machine learning
G. R. Davies, V. Silva Aguirre, T. R. Bedding +16
\Kepler has revolutionised our understanding of both exoplanets and their host stars. Asteroseismology is a valuable tool in the characterisation of stars and \Kepler is an excelle…
The lost sunspot cycle: New support from Be10 measurements
C. Karoff, F. Inceoglu, M. F. Knudsen +2
It has been suggested that the deficit in the number of spots on the surface of the Sun between 1790 and 1830, known as the Dalton minimum, contained an extra cycle that was not id…
Magnetic activity, differential rotation and dynamo action in the pulsating F9IV star KIC 5955122
A. Bonanno, H. -E. Fröhlich, C. Karoff +3
We present photometric spot modeling of the nearly four-year long light-curve of the Kepler target KIC 5955122 in terms of persisting dark circular surface features. With a Bayesia…
Rotation and magnetism of Kepler pulsating solar-like stars. Towards asteroseismically calibrated age-rotation relations
R. A. Garcia, T. Ceillier, D. Salabert +16
Kepler ultra-high precision photometry of long and continuous observations provides a unique dataset in which surface rotation and variability can be studied for thousands of stars…
Fundamental Properties of Kepler Planet-Candidate Host Stars using Asteroseismology
Daniel Huber, William J. Chaplin, Jørgen Christensen-Dalsgaard +31
We have used asteroseismology to determine fundamental properties for 66 Kepler planet-candidate host stars, with typical uncertainties of 3% and 7% in radius and mass, respectivel…
Calibrating Convective properties of Solar-like Stars in the Kepler Field of View
Ana Bonaca, Joel D. Tanner, Sarbani Basu +24
Stellar models generally use simple parametrizations to treat convection. The most widely used parametrization is the so-called "Mixing Length Theory" where the convective eddy siz…
Kepler-21b: A 1.6REarth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070
Steve B. Howell, Jason F. Rowe, Stephen T. Bryson +63
We present Kepler observations of the bright (V=8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by…
Fundamental properties of five Kepler stars using global asteroseismic quantities and ground-based observations
O. L. Creevey, G. Dogan, A. Frasca +34
We present an asteroseismic study of the solar-like stars KIC 11395018, KIC 10273246, KIC 10920273, KIC 10339342, and KIC 11234888 using short-cadence time series of more than eigh…
Asteroseismic diagrams from a survey of solar-like oscillations with Kepler
Timothy R. White, Timothy R. Bedding, Dennis Stello +30
Photometric observations made by the NASA Kepler Mission have led to a dramatic increase in the number of main-sequence and subgiant stars with detected solar-like oscillations. We…
Modeling Kepler Observations of Solar-like Oscillations in the Red-giant Star HD 186355
Chen Jiang, Biwei Jiang, Jorgen Christensen-Dalsgaard +11
We have analysed oscillations of the red giant star HD 186355 observed by the NASA Kepler satellite. The data consist of the first five quarters of science operations of Kepler, wh…
Constructing a one-solar-mass evolutionary sequence using asteroseismic data from \textit{Kepler}
V. Silva Aguirre, W. J. Chaplin, J. Ballot +39
Asteroseismology of solar-type stars has entered a new era of large surveys with the success of the NASA \textit{Kepler} mission, which is providing exquisite data on oscillations…
Global asteroseismic properties of solar-like oscillations observed by Kepler : A comparison of complementary analysis methods
G. A. Verner, Y. Elsworth, W. J. Chaplin +24
We present the asteroseismic analysis of 1948 F-, G- and K-type main-sequence and subgiant stars observed by the NASA {\em Kepler Mission}. We detect and characterise solar-like os…
Evidence for the impact of stellar activity on the detectability of solar-like oscillations observed by Kepler
W. J. Chaplin, T. R. Bedding, A. Bonanno +37
We use photometric observations of solar-type stars, made by the NASA Kepler Mission, to conduct a statistical study of the impact of stellar surface activity on the detectability…
Solar-like oscillations in KIC11395018 and KIC11234888 from 8 months of Kepler data
S. Mathur, R. Handberg, T. L. Campante +34
We analyze the photometric short-cadence data obtained with the Kepler Mission during the first eight months of observations of two solar-type stars of spectral types G and F: KIC…
A precise asteroseismic age and radius for the evolved Sun-like star KIC 11026764
T. S. Metcalfe, M. J. P. F. G. Monteiro, M. J. Thompson +55
The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-…
How did the Sun affect the climate when life evolved on the Earth?
C. Karoff, H. Svensmark
Using kappa Ceti as a proxy for the young Sun we show that not only was the young Sun much more effective in protecting the Earth environment from galactic cosmic rays than the pre…