139 citations · 990 across the 25 of their papers we have counts for
25 papers
Asteroseismology and Spectropolarimetry of the Exoplanet Host Star Serpentis
Travis S. Metcalfe, Derek Buzasi, Daniel Huber +31
The bright star Ser hosts a hot Neptune with a minimum mass of 13.6 and a 15.5 day orbit. It also appears to be a solar analog, with a mean rotation period of 25.8 d…
Temporal variation of the photometric magnetic activity for the Sun and Kepler solar-like stars
A. R. G. Santos, S. Mathur, R. A. García +9
The photometric time series of solar-like stars can exhibit rotational modulation due to active regions co-rotating with the stellar surface, allowing us to constrain stellar rotat…
Convolutional Neural Networks and Stokes Response Functions
Rebecca Centeno, Natasha Flyer, Lipi Mukherjee +4
In this work, we study the information content learned by a convolutional neural network (CNN) when trained to carry out the inverse mapping between a database of synthetic Ca II i…
Magnetic and Rotational Evolution of CrB from Asteroseismology with TESS
Travis S. Metcalfe, Jennifer L. van Saders, Sarbani Basu +15
During the first half of main-sequence lifetimes, the evolution of rotation and magnetic activity in solar-type stars appears to be strongly coupled. Recent observations suggest th…
Measuring the magnetic origins of solar flares, CMEs and Space Weather
Philip Judge, Matthias Rempel, Rana Ezzeddine +11
We take a broad look at the problem of identifying the magnetic solar causes of space weather. With the lackluster performance of extrapolations based upon magnetic field measureme…
Deciphering Solar Magnetic Activity: 140 Years Of The `Extended Solar Cycle' -- Mapping the Hale Cycle
Scott W. McIntosh, Robert J. Leamon, Ricky Egeland +6
We investigate the occurrence of the "extended solar cycle" (ESC) as it occurs in a host observational data spanning 140 years. Investigating coronal, chromospheric, photospheric a…
The Evolution of Rotation and Magnetic Activity in 94 Aqr Aa from Asteroseismology with TESS
Travis S. Metcalfe, Jennifer L. van Saders, Sarbani Basu +29
Most previous efforts to calibrate how rotation and magnetic activity depend on stellar age and mass have relied on observations of clusters, where isochrones from stellar evolutio…
Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude
Scott W. McIntosh, Sandra C. Chapman, Robert J. Leamon +2
The Sun exhibits a well-observed modulation in the number of spots on its disk over a period of about 11 years. From the dawn of modern observational astronomy sunspots have presen…
Sun-like Stars Shed Light on Solar Climate Forcing
P. G. Judge, R. Egeland, G. W. Henry
Recently published, precise stellar photometry of 72 Sun-like stars obtained at the Fairborn Observatory between 1993 and 2017 is used to set limits on the solar forcing of Earth's…
Age dating of an early Milky Way merger via asteroseismology of the naked-eye star Indi
William J. Chaplin, Aldo M. Serenelli, Andrea Miglio +81
Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies. While these accreted stellar populations can be forensically identified as kinematic…
Waldmeier Effect in Stellar Cycles
Suyog Garg, Bidya Binay Karak, Ricky Egeland +2
One of the most robust features of the solar magnetic cycle is that the stronger cycles rise faster than the weaker ones. This is popularly known as the Waldmeier Effect, which is…
Astro2020 Science White Paper: Stellar Physics and Galactic Archeology using Asteroseismology in the 2020's
Daniel Huber, Sarbani Basu, Paul Beck +32
Asteroseismology is the only observational tool in astronomy that can probe the interiors of stars, and is a benchmark method for deriving fundamental properties of stars and exopl…
What the sudden death of solar cycles can tell us about the nature of the solar interior
Scott W. McIntosh, Robert J. Leamon, Ricky Egeland +3
We observe the abrupt end of solar activity cycles at the Sun's equator by combining almost 140 years of observations from ground and space. These "terminator" events appear to be…
Understanding the Limitations of Gyrochronology for Old Field Stars
Travis S. Metcalfe, Ricky Egeland
Nearly half a century has passed since the initial indications that stellar rotation slows while chromospheric activity weakens with a power-law dependence on age, the so-called Sk…
Deconvolving the HD 81809 binary: rotational and activity evidence for a subgiant with a Sun-like cycle
Ricky Egeland
HD 81809 has one of the highest quality activity cycles from the sample of stars synoptically observed in the Mount Wilson Observatory HK Project. However, this object is in fact a…
Sunstardb: a database for the study of stellar magnetism and the solar-stellar connection
Ricky Egeland
The "solar-stellar connection" began as a relatively small field of research focused on understanding the processes that generate magnetic field in stars and which sometimes lead t…
The magnetic future of the Sun
Philip Judge, RIcky Egeland, Travis Metcalfe +2
We analyze space- and ground-based data for the old (~Gyr) solar analogs 16 Cyg A and B. The stars were observed with the Cosmic Origins UV Spectrographs on the Hubble S…
Evolution of Long Term Variability in Solar Analogs
Ricky Egeland, Willie Soon, Sallie Baliunas +2
Earth is the only planet known to harbor life, therefore we may speculate on how the nature of the Sun-Earth interaction is relevant to life on Earth, and how the behavior of other…
The Mount Wilson Observatory S-index of the Sun
Ricky Egeland, Willie Soon, Sallie Baliunas +3
The most commonly used index of stellar magnetic activity is the instrumental flux scale of singly-ionized calcium H & K line core emission, S, developed by the Mount Wilson Observ…
Dynamo Sensitivity in Solar Analogs with 50 Years of Ca II H & K Activity
Ricky Egeland, Willie Soon, Sallie Baliunas +3
The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11…
Photospheric and chromospheric magnetic activity of seismic solar analogs. Observational inputs on the solar/stellar connection from Kepler and Hermes
D. Salabert, R. A. Garcia, P. G. Beck +8
We identify a set of 18 solar analogs among the seismic sample of solar-like stars observed by the Kepler satellite rotating between 10 and 40 days. This set is constructed using t…
Stellar Evidence that the Solar Dynamo may be in Transition
Travis S. Metcalfe, Ricky Egeland, Jennifer van Saders
Precise photometry from the Kepler space telescope allows not only the measurement of rotation in solar-type field stars, but also the determination of reliable masses and ages fro…
Magnetic variability in the young solar analog KIC 10644253: Observations from the Kepler satellite and the HERMES spectrograph
D. Salabert, C. Regulo, R. A. Garcia +12
The continuous photometric observations collected by the Kepler satellite over 4 years provide a whelm of data with an unequalled quantity and quality for the study of stellar evol…
Sun-Like Magnetic Cycles in the Rapidly-Rotating Young Solar Analog HD 30495
Ricky Egeland, Travis S. Metcalfe, Jeffrey C. Hall +1
A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar…