Zobrazeno 1 - 10
of 825
pro vyhledávání: '"Keivan G Stassun"'
Autor:
Keivan G. Stassun, Marina Kounkel
Publikováno v:
The Astrophysical Journal Letters, Vol 967, Iss 2, p L36 (2024)
We have assembled a sample of ∼8200 stars with spectral types F5V–M5V, all having directly measured X-ray luminosities from eROSITA and rotation periods from TESS and having empirically estimated ages via their membership in stellar clusters and
Externí odkaz:
https://doaj.org/article/a77a088117984f629d5d50cce1a22547
Autor:
Alexander P. Ji, Sanjana Curtis, Nicholas Storm, Vedant Chandra, Kevin C. Schlaufman, Keivan G. Stassun, Alexander Heger, Marco Pignatari, Adrian M. Price-Whelan, Maria Bergemann, Guy S. Stringfellow, Carla Fröhlich, Henrique Reggiani, Erika M. Holmbeck, Jamie Tayar, Shivani P. Shah, Emily J. Griffith, Chervin F. P. Laporte, Andrew R. Casey, Keith Hawkins, Danny Horta, William Cerny, Pierre Thibodeaux, Sam A. Usman, João A. S. Amarante, Rachael L. Beaton, Phillip A. Cargile, Cristina Chiappini, Charlie Conroy, Jennifer A. Johnson, Juna A. Kollmeier, Haining Li, Sarah Loebman, Georges Meynet, Dmitry Bizyaev, Joel R. Brownstein, Pramod Gupta, Sean Morrison, Kaike Pan, Solange V. Ramirez, Hans-Walter Rix, José Sánchez-Gallego
Publikováno v:
The Astrophysical Journal Letters, Vol 961, Iss 2, p L41 (2024)
Stars that formed with an initial mass of over 50 M _⊙ are very rare today, but they are thought to be more common in the early Universe. The fates of those early, metal-poor, massive stars are highly uncertain. Most are expected to directly collap
Externí odkaz:
https://doaj.org/article/cb019f1a53ca4e8bbf8ef53fff9533f7
Autor:
Travis S. Metcalfe, Klaus G. Strassmeier, Ilya V. Ilyin, Derek Buzasi, Oleg Kochukhov, Thomas R. Ayres, Sarbani Basu, Ashley Chontos, Adam J. Finley, Victor See, Keivan G. Stassun, Jennifer L. van Saders, Aldo G. Sepulveda, George R. Ricker
Publikováno v:
The Astrophysical Journal Letters, Vol 960, Iss 1, p L6 (2024)
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 suggestion that the star could be experiencing a magnetic grand minimum. However, the 50 yr time serie
Externí odkaz:
https://doaj.org/article/be59577f1d4549889d6d5c21333540b7
Autor:
Travis S. Metcalfe, Jennifer L. van Saders, Daniel Huber, Derek Buzasi, Rafael A. García, Keivan G. Stassun, Sarbani Basu, Sylvain N. Breton, Zachary R. Claytor, Enrico Corsaro, Martin B. Nielsen, J. M. Joel Ong, Nicholas Saunders, Amalie Stokholm, Timothy R. Bedding
Publikováno v:
The Astrophysical Journal, Vol 974, Iss 1, p 31 (2024)
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 estimated to be near 27 days. As a Southern Hemisphere target, it was not monitored by long-term s
Externí odkaz:
https://doaj.org/article/14e6e8c7daee46e38e44e35482b4bc18
Two Young Eclipsing Binaries in Orion with Temperatures and Radii Affected by Spots and Third Bodies
Autor:
Marina Kounkel, Keivan G. Stassun
Publikováno v:
The Astronomical Journal, Vol 168, Iss 3, p 134 (2024)
In this work we present a model of two young eclipsing binaries in the Orion complex. Both heavily spotted, they present radii and temperatures that are in disagreement with the predictions of standard stellar models. 2M05−06 consists of two stars
Externí odkaz:
https://doaj.org/article/25ca4bc285fa45ab95b2d63af02a1584
Autor:
Daria Pidhorodetska, Emily A. Gilbert, Stephen R. Kane, Thomas Barclay, Alex S. Polanski, Michelle L. Hill, Keivan G. Stassun, Steven Giacalone, David R. Ciardi, Andrew W. Boyle, Steve B. Howell, Jorge Lillo-Box, Mason G. MacDougall, Tara Fetherolf, Natalie M. Batalha, Ian J. M. Crossfield, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Howard Isaacson, Erik A. Petigura, Paul Robertson, Lauren M. Weiss, Isabel Angelo, Corey Beard, Aida Behmard, Sarah Blunt, Casey L. Brinkman, Ashley Chontos, Fei Dai, Paul A. Dalba, Rae Holcomb, Jack Lubin, Andrew W. Mayo, Joseph M. Akana Murphy, Malena Rice, Ryan Rubenzahl, Nicholas Scarsdale, Emma V. Turtelboom, Dakotah Tyler, Judah Van Zandt, Edward W. Schwieterman
Publikováno v:
The Astronomical Journal, Vol 168, Iss 3, p 135 (2024)
Exoplanet discoveries have revealed a dramatic diversity of planet sizes across a vast array of orbital architectures. Sub-Neptunes are of particular interest; due to their absence in our own solar system, we rely on demographics of exoplanets to bet
Externí odkaz:
https://doaj.org/article/c4963d5fd69444958a6bdfc6807d6461
Autor:
Mark R. Giovinazzi, Bryson Cale, Jason D. Eastman, Joseph E. Rodriguez, Cullen H. Blake, Keivan G. Stassun, Andrew Vanderburg, Michelle Kunimoto, Adam L. Kraus, Joseph Twicken, Thomas G. Beatty, Cayla M. Dedrick, Jonathan Horner, John A. Johnson, Samson A. Johnson, Nate McCrady, Peter Plavchan, David H. Sliski, Maurice L. Wilson, Robert A. Wittenmyer, Jason T. Wright, Marshall C. Johnson, Mark E. Rose, Matthew Cornachione
Publikováno v:
The Astronomical Journal, Vol 168, Iss 3, p 118 (2024)
We present a new analysis of the KELT-24 system, comprising a well-aligned hot Jupiter, KELT-24 b, and a bright ( V = 8.3), nearby ( d = 96.9 pc) F-type host star. KELT-24 b was independently discovered by two groups in 2019, with each reporting best
Externí odkaz:
https://doaj.org/article/e5f27cec64154aa4925458370eb7cda3
Autor:
Fábio Wanderley, Katia Cunha, Oleg Kochukhov, Verne V. Smith, Diogo Souto, Lyra Cao, Kevin Covey, Steven R. Majewski, Cintia Martinez, Philip S. Muirhead, Marc Pinsonneault, C. Allende Prieto, Keivan G. Stassun
Publikováno v:
The Astrophysical Journal, Vol 971, Iss 1, p 112 (2024)
Average magnetic field measurements are presented for 62 M-dwarf members of the Pleiades open cluster, derived from Zeeman-enhanced Fe i lines in the H band. A Markov Chain Monte Carlo methodology was employed to model magnetic filling factors using
Externí odkaz:
https://doaj.org/article/039ed866462d4864873280e4f186cc50
Autor:
Vanshree Bhalotia, Daniel Huber, Jennifer L. van Saders, Travis S. Metcalfe, Keivan G. Stassun, Timothy R. White, Víctor Aguirre Børsen-Koch, Warrick H. Ball, Sarbani Basu, Aldo M. Serenelli, Erica Sawczynec, Joyce A. Guzik, Andrew W. Howard, Howard Isaacson
Publikováno v:
The Astrophysical Journal, Vol 970, Iss 2, p 166 (2024)
Stellar spin down is a critical yet poorly understood component of stellar evolution. In particular, results from the Kepler Mission imply that mature age, solar-type stars have inefficient magnetic braking, resulting in a stalled spin-down rate. How
Externí odkaz:
https://doaj.org/article/06a4a282b81a4e0695c3a216ca0e03e8
Autor:
William Grimble, Joel Kastner, Christophe Pinte, Beth Sargent, David A. Principe, Annie Dickson-Vandervelde, Aurora Belén Aguayo, Claudio Caceres, Matthias R. Schreiber, Keivan G. Stassun
Publikováno v:
The Astrophysical Journal, Vol 970, Iss 2, p 137 (2024)
Our understanding of how exoplanets form and evolve relies on analyses of both the mineralogy of protoplanetary disks and their detailed structures; however, these key complementary aspects of disks are usually studied separately. We present initial
Externí odkaz:
https://doaj.org/article/119afaf23fb54d809f79a342453e1d46