Search Results - "Metcalfe, Travis S."

Magnetic Evolution and the Disappearance of Sun-Like Activity Cycles by Metcalfe, Travis S., van Saders, Jennifer

“…After decades of effort, the solar activity cycle is exceptionally well characterized, but it remains poorly understood. Pioneering work at the Mount Wilson…”
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Evolution of Co-existing Long and Short Period Stellar Activity Cycles by Brandenburg, Axel, Mathur, Savita, Metcalfe, Travis S.

“…The magnetic activity of the Sun becomes stronger and weaker over roughly an 11 year cycle, modulating the radiation and charged particle environment…”
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Understanding the Limitations of Gyrochronology for Old Field Stars by Metcalfe, Travis S., Egeland, Ricky

“…Nearly half a century has passed since the initial indications that stellar rotation slows while chromospheric activity weakens with a power-law dependence on…”
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Weakened magnetic braking as the origin of anomalously rapid rotation in old field stars by van Saders, Jennifer L., Ceillier, Tugdual, Metcalfe, Travis S., Aguirre, Victor Silva, Pinsonneault, Marc H., García, Rafael A., Mathur, Savita, Davies, Guy R.

“…The age of a young to middle-aged star can be determined from how quickly or slowly it rotates, but the relationship breaks down for old stars; models now show…”
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CoRoT Reveals a Magnetic Activity Cycle in a Sun-Like Star by García, Rafael A, Mathur, Savita, Salabert, David, Ballot, Jérôme, Régulo, Clara, Metcalfe, Travis S, Baglin, Annie

“…The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT…”
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The Origin of Weakened Magnetic Braking in Old Solar Analogs by Metcalfe, Travis S., Finley, Adam J., Kochukhov, Oleg, See, Victor, Ayres, Thomas R., Stassun, Keivan G., van Saders, Jennifer L., Clark, Catherine A., Godoy-Rivera, Diego, Ilyin, Ilya V., Pinsonneault, Marc H., Strassmeier, Klaus G., Petit, Pascal

“…Abstract The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of…”
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The Influence of Metallicity on Stellar Differential Rotation and Magnetic Activity by Karoff, Christoffer, Metcalfe, Travis S., Santos, Ângela R. G., Montet, Benjamin T., Isaacson, Howard, Witzke, Veronika, Shapiro, Alexander I., Mathur, Savita, Davies, Guy R., Lund, Mikkel N., Garcia, Rafael A., Brun, Allan S., Salabert, David, Avelino, Pedro P., Saders, Jennifer van, Egeland, Ricky, Cunha, Margarida S., Campante, Tiago L., Chaplin, William J., Krivova, Natalie, Solanki, Sami K., Stritzinger, Maximilian, Knudsen, Mads F.

“…Observations of Sun-like stars over the past half-century have improved our understanding of how magnetic dynamos, like that responsible for the 11 yr solar…”
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Stellar Cruise Control: Weakened Magnetic Braking Leads to Sustained Rapid Rotation of Old Stars by Saunders, Nicholas, van Saders, Jennifer L., Lyttle, Alexander J., Metcalfe, Travis S., Li, Tanda, Davies, Guy R., Hall, Oliver J., Ball, Warrick H., Townsend, Richard, Creevey, Orlagh, Dodds, Curt

“…Abstract Despite a growing sample of precisely measured stellar rotation periods and ages, the strength of magnetic braking and the degree of departure from…”
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TESS Asteroseismology of β Hydri: A Subgiant with a Born-again Dynamo by Metcalfe, Travis S., van Saders, Jennifer L., Huber, Daniel, Buzasi, Derek, García, Rafael A., Stassun, Keivan G., Basu, Sarbani, Breton, Sylvain N., Claytor, Zachary R., Corsaro, Enrico, Nielsen, Martin B., Ong, J. M. Joel, Saunders, Nicholas, Stokholm, Amalie, Bedding, Timothy R.

“…Abstract The solar-type subgiant β Hyi has long been studied as an old analog of the Sun. Although the rotation period has never been measured directly, it was…”
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A New Asteroseismic Kepler Benchmark Constrains the Onset of Weakened Magnetic Braking in Mature Sun-like Stars by Bhalotia, Vanshree, Huber, Daniel, van Saders, Jennifer L., Metcalfe, Travis S., Stassun, Keivan G., White, Timothy R., Aguirre Børsen-Koch, Víctor, Ball, Warrick H., Basu, Sarbani, Serenelli, Aldo M., Sawczynec, Erica, Guzik, Joyce A., Howard, Andrew W., Isaacson, Howard

“…Abstract Stellar spin down is a critical yet poorly understood component of stellar evolution. In particular, results from the Kepler Mission imply that mature…”
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Constraints on Magnetic Braking from the G8 Dwarf Stars 61 UMa and τ Cet by Metcalfe, Travis S., Strassmeier, Klaus G., Ilyin, Ilya V., van Saders, Jennifer L., Ayres, Thomas R., Finley, Adam J., Kochukhov, Oleg, Petit, Pascal, See, Victor, Stassun, Keivan G., Jeffers, Sandra V., Marsden, Stephen C., Morin, Julien, Vidotto, Aline A.

“…Abstract During the first half of their main-sequence lifetimes, stars rapidly lose angular momentum to their magnetized winds, a process known as magnetic…”
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ASTEROSEISMIC ESTIMATE OF HELIUM ABUNDANCE OF A SOLAR ANALOG BINARY SYSTEM by Verma, Kuldeep, Faria, Joao P, Antia, H M, Basu, Sarbani, MAZUMDAR, ANWESH, MONTEIRO, MARIO J P F G, APPOURCHAUX, THIERRY, Chaplin, William J, Garcia, Rafael A, Metcalfe, Travis S

“…16 Cyg A and B are among the brightest stars observed by Kepler. What makes these stars more interesting is that they are solar analogs. 16 Cyg A and B exhibit…”
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Weakened Magnetic Braking in the Exoplanet Host Star 51 Peg by Metcalfe, Travis S., Strassmeier, Klaus G., Ilyin, Ilya V., Buzasi, Derek, Kochukhov, Oleg, Ayres, Thomas R., Basu, Sarbani, Chontos, Ashley, Finley, Adam J., See, Victor, Stassun, Keivan G., van Saders, Jennifer L., Sepulveda, Aldo G., Ricker, George R.

“…Abstract The consistently low activity level of the old solar analog 51 Peg not only facilitated the discovery of the first hot Jupiter, but also led to the…”
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Asteroseismology and Spectropolarimetry of the Exoplanet Host Star λ Serpentis by Metcalfe, Travis S., Buzasi, Derek, Huber, Daniel, Pinsonneault, Marc H., van Saders, Jennifer L., Ayres, Thomas R., Basu, Sarbani, Drake, Jeremy J., Egeland, Ricky, Kochukhov, Oleg, Petit, Pascal, Saar, Steven H., See, Victor, Stassun, Keivan G., Li, Yaguang, Bedding, Timothy R., Breton, Sylvain N., Finley, Adam J., García, Rafael A., Kjeldsen, Hans, Nielsen, Martin B., Ong, J. M. Joel, Rørsted, Jakob L., Stokholm, Amalie, Winther, Mark L., Clark, Catherine A., Godoy-Rivera, Diego, Ilyin, Ilya V., Strassmeier, Klaus G., Jeffers, Sandra V., Marsden, Stephen C., Vidotto, Aline A., Baliunas, Sallie, Soon, Willie

“…Abstract The bright star λ Ser hosts a hot Neptune with a minimum mass of 13.6 M ⊕ and a 15.5 day orbit. It also appears to be a solar analog, with a mean…”
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Stellar Activity Cycles by Jeffers, Sandra V., Kiefer, René, Metcalfe, Travis S.

“…The magnetic field of the Sun is generated by internal dynamo process with a cyclic period of 11 years or a 22 year magnetic cycle. The signatures of the Sun’s…”
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Scaling and Evolution of Stellar Magnetic Activity by Işık, Emre, van Saders, Jennifer L., Reiners, Ansgar, Metcalfe, Travis S.

“…Magnetic activity is a ubiquitous feature of stars with convective outer layers, with implications from stellar evolution to planetary atmospheres…”
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SUN-LIKE MAGNETIC CYCLES IN THE RAPIDLY ROTATING YOUNG SOLAR ANALOG HD 30495 by Egeland, Ricky, Metcalfe, Travis S., Hall, Jeffrey C., Henry, Gregory W.

“…ABSTRACT A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but…”
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Stellar Spin-Orbit Misalignment in a Multiplanet System by Huber, Daniel, Carter, Joshua A., Barbieri, Mauro, Miglio, Andrea, Deck, Katherine M., Fabrycky, Daniel C., Montet, Benjamin T., Buchhave, Lars A., Chaplin, William J., Hekker, Saskia, Montalbán, Josefina, Sanchis-Ojeda, Roberto, Basu, Sarbani, Bedding, Timothy R., Campante, Tiago L., Christensen-Dalsgaard, Jørgen, Elsworth, Yvonne P., Stello, Dennis, Arentoft, Torben, Ford, Eric B., Gilliland, Ronald L., Handberg, Rasmus, Howard, Andrew W., Isaacson, Howard, Johnson, John Asher, Karoff, Christoffer, Kawaler, Steven D., Kjeldsen, Hans, Latham, David W., Lund, Mikkel N., Lundkvist, Mia, Marcy, Geoffrey W., Metcalfe, Travis S., Aguirre, Victor Silva, Winn, Joshua N.

“…Stars hosting hot Jupiters are often observed to have high obliquities, whereas stars with multiple coplanar planets have been seen to have low obliquities…”
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Seismic inference of 57 stars using full-length Kepler data sets by Creevey, Orlagh, Metcalfe, Travis S., Salabert, David, Mathur, Savita, Schultheis, Mathias, García, Rafael A., Thévenin, Frédéric, Bazot, Michaël, Xu, Haiying

“…We present stellar properties of 57 stars from a seismic inference using full-length data sets from Kepler (mass, age, radius, distances). These stars comprise…”
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Brightness Fluctuation Spectra of Sun-like Stars. I. The Mid-frequency Continuum by Brown, Timothy M., García, Rafael A., Mathur, Savita, Metcalfe, Travis S., Santos, Ângela R. G.

“…Abstract 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…”
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