Zobrazeno 1 - 10
of 192
pro vyhledávání: '"GUINAN, EDWARD F."'
Autor:
Engle, Scott G., Guinan, Edward F.
Age is a fundamental stellar property, yet for many stars it is difficult to reliably determine. For M dwarfs it has been notoriously so. Due to their lower masses, core hydrogen fusion proceeds at a much slower rate in M dwarfs than it does in more
Externí odkaz:
http://arxiv.org/abs/2307.01136
The processes that shape the extended atmospheres of red supergiants (RSGs), heat their chromospheres, create molecular reservoirs, drive mass loss, and create dust remain poorly understood. Betelgeuse's V-band "Great Dimming" event of 2019 September
Externí odkaz:
http://arxiv.org/abs/2011.05982
Autor:
Dupree, Andrea K., Strassmeier, Klaus G., Matthews, Lynn D., Uitenbroek, Han, Calderwood, Thomas, Granzer, Thomas, Guinan, Edward F, Leike, Reimar, Montargès, Miguel, Richards, Anita M. S., Wasatonic, Richard, Weber, Michael
The bright supergiant, Betelgeuse (Alpha Orionis, HD 39801) experienced a visual dimming during 2019 December and the first quarter of 2020 reaching an historic minimum 2020 February 7$-$13. During 2019 September-November, prior to the optical dimmin
Externí odkaz:
http://arxiv.org/abs/2008.04945
Autor:
Harper, Graham M., DeWitt, Curtis N., Richter, Matthew J., Guinan, Edward F., Wasatonic, Richard, Ryde, Nils, Edward, Montiel, J., Townsend, Amanda J.
In 2019 October Betelgeuse began a decline in V-band brightness that went beyond the minimum expected from its quasi-periodic ~420 day cycle, becoming the faintest in recorded photometric history. Observations obtained in 2019 December with VLT/SPHER
Externí odkaz:
http://arxiv.org/abs/2003.13884
Autor:
Carpenter, Kenneth G., van Belle, Gerard, Brown, Alexander, Cranmer, Steven R., Drake, Jeremy, Dupree, Andrea K., Creech-Eakman, Michelle, Evans, Nancy R., Grady, Carol A., Guinan, Edward F., Harper, Graham, Karovska, Margarita, Kolenberg, Katrien, Labeyrie, Antoine, Linsky, Jeffrey, Peters, Geraldine J., Rau, Gioia, Ridgway, Stephen, Roettenbacher, Rachael M., Saar, Steven H., Walter, Frederick M., Wood, Brian
We summarize some of the compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-milliarcsec (sub-mas) angular resolution, UV-Optical spectral imaging observations, which can reveal the details o
Externí odkaz:
http://arxiv.org/abs/1908.05665
Autor:
Engle, Scott G., Guinan, Edward F., Harper, Dr. Graham M., Cuntz, Prof. Manfred, Evans, Dr. Nancy R., Neilson, Dr. Hilding, Fawzy, Dr. Diaa E.
Publikováno v:
ApJ, 838 (2017), 67
From our Secret Lives of Cepheids program, the prototype Classical Cepheid, $\delta$ Cep, is found to be an X-ray source with periodic pulsation-modulated X-ray variations. This finding complements our earlier reported phase-dependent FUV--UV emissio
Externí odkaz:
http://arxiv.org/abs/1702.06560
Autor:
Ribas, Ignasi, Bolmont, Emeline, Selsis, Franck, Reiners, Ansgar, Leconte, Jeremy, Raymond, Sean N., Engle, Scott G., Guinan, Edward F., Morin, Julien, Turbet, Martin, Forget, Francois, Anglada-Escude, Guillem
Publikováno v:
A&A 596, A111 (2016)
Proxima b is a planet with a minimum mass of 1.3 MEarth orbiting within the habitable zone (HZ) of Proxima Centauri, a very low-mass, active star and the Sun's closest neighbor. Here we investigate a number of factors related to the potential habitab
Externí odkaz:
http://arxiv.org/abs/1608.06813
Autor:
Neilson, Hilding R., Engle, Scott G., Guinan, Edward F., Bisol, Alexandra C., Butterworth, Neil
The classical Cepheid $l$ Carinae is an essential calibrator of the Cepheid Leavitt Law as a rare long-period Galactic Cepheid. Understanding the properties of this star will also constrain the physics and evolution of massive ($M \ge 8$ $M_\odot$) C
Externí odkaz:
http://arxiv.org/abs/1604.03128
As part of Villanova's Living with a Red Dwarf program, we have obtained UV, X-ray and optical data of the Population II red dwarf -- Kapteyn's Star. Kapteyn's Star is noteworthy for its large proper motions and high RV of ~+245 km s^-1. As the neare
Externí odkaz:
http://arxiv.org/abs/1602.01912
Autor:
O'Gorman, Eamon, Harper, Graham M., Brown, Alexander, Guinan, Edward F., Richards, Anita M. S., Vlemmings, Wouter, Wasatonic, Richard
We use the Very Large Array (VLA) in the A configuration with the Pie Town (PT) Very Long Baseline Array (VLBA) antenna to spatially resolve the extended atmosphere of Betelgeuse over multiple epochs at 0.7, 1.3, 2.0, 3.5, and 6.1 cm. The extended at
Externí odkaz:
http://arxiv.org/abs/1506.07536