Results 31 to 40 of about 34,754,919 (296)

The State Complexity of Star-Complement-Star [PDF]

, 2012
We resolve an open question by determining matching (asymptotic) upper and lower bounds on the state complexity of the operation that sends a language L to (c(L*))*, where c() denotes complement.
Galina Jirásková, Jeffrey O. Shallit
openaire   +2 more sources

K2 Photometry and Long-Term Hα Variability in Four Previously Unreported Be Stars

Universe
Classical Be stars are key laboratories for investigating how rapid rotation, pulsations, and mass loss couple to the formation and evolution of circumstellar decretion disks.
Alan Wagner Pereira, Eduardo Janot-Pacheco, Jéssica Mayara Eidam, Bergerson Van Hallen Vieira da Silva, M. Cristina Rabello-Soares, Laerte Andrade, Marcelo Emilio   +6 more
doaj   +1 more source

Reddening-Free Q Parameters to Classify B-Type Stars with Emission Lines

Galaxies, 2023
The emission-line B-type stars constitute a heterogeneous group. Many of these stars show similar optical spectroscopic features and color indices, making it difficult to classify them adequately by means of photometric and spectroscopic techniques. Thus,
Yael Aidelman, Lydia Sonia Cidale
doaj   +1 more source

Radial-velocity measurements of subdwarf B stars [PDF]

, 2011
Subdwarf B (sdB) stars are hot, subluminous stars which are thought to be core-helium burning with thin hydrogen envelopes. The mechanism by which these stars lose their envelopes has been controversial, but it has been argued that binary star ...
Copperwheat, CM, Maxted, P. F. L., Morales-Rueda, L., Morales-Rueda, L, Heber, U, L. Morales-Rueda, U. Heber, Copperwheat, C. M., Heber, U., C. M. Copperwheat, T. R. Marsh, Marsh, TR, Maxted, PFL, Marsh, T. R., P. F. L. Maxted   +14 more
core   +1 more source

CHIME Discovery of a Binary Pulsar with a Massive Nondegenerate Companion

The Astrophysical Journal, 2023
Of the more than 3000 radio pulsars currently known, only ∼300 are in binary systems, and only five of these consist of young pulsars with massive nondegenerate companions.
Bridget C. Andersen, Emmanuel Fonseca, J. W. McKee, B. W. Meyers, Jing Luo, C. M. Tan, I. H. Stairs, Victoria M. Kaspi, M. H. van Kerkwijk, Mohit Bhardwaj, P. J. Boyle, Kathryn Crowter, Paul B. Demorest, Fengqiu A. Dong, Deborah C. Good, Jane F. Kaczmarek, Calvin Leung, Kiyoshi W. Masui, Arun Naidu, Cherry Ng, Chitrang Patel, Aaron B. Pearlman, Ziggy Pleunis, Masoud Rafiei-Ravandi, Mubdi Rahman, Scott M. Ransom, Kendrick M. Smith, Shriharsh P. Tendulkar   +27 more
doaj   +1 more source

Exploring the Long-term Temporal Variability in Polarization through Multiepoch Optical Spectropolarimetry. I. A Sample of Herbig Ae/Be and Classical Be Stars

The Astronomical Journal
Polarization signatures across emission line features, together with their temporal evolution, offer a powerful probe of the circumstellar environments of astrophysical sources, on spatial scales otherwise inaccessible to direct imaging techniques ...
Arijit Maiti, Mudit K. Srivastava
doaj   +1 more source

Rainbow’s stars [PDF]

The European Physical Journal C, 2017
In recent years, a growing interest on the equilibrium of compact astrophysical objects like white dwarf and neutron stars has been manifested. In particular, various modifications due to Planck scale energy effects have been considered. In this paper we analyze the modification induced by Gravity's Rainbow on the equilibrium configurations described ...
Garattini, Remo, Mandanici, Gianluca
openaire   +3 more sources

European Standard Clinical Practice Guideline and EXPeRT Recommendations for the Diagnosis and Management of Gastroenteropancreatic Neuroendocrine Neoplasms in Children and Adolescents

Pediatric Blood &Cancer, EarlyView.
ABSTRACT Pediatric gastroenteropancreatic neuroendocrine neoplasms (GEP‐NENs) are extremely rare and clinically heterogeneous. Management has largely been extrapolated from adult practice. This European Standard Clinical Practice Guideline (ESCP), developed by the EXPeRT network in collaboration with adult NEN experts, provides (adult) evidence ...
Michaela Kuhlen, Calogero Virgone, Antje Redlich, Michael Abele, Ricardo Lopez‐Almaraz, Tal Ben‐Ami, Ewa Bien, Gianni Bisogno, Maja Mazic Cesen, Andrea Ferrari, Malgorzata A. Krawczyk, Yves Reguerre, Dominik T. Schneider, Ines B. Brecht, Charlotte Rigaud, Bilgehan Yalcin, Rainer Claus, Christian Vokuhl, Constantin Lapa, Jörg Fuchs, Segolene Hescot, Thomas Walter, Julien Hadoux, Daniel Orbach   +23 more
wiley   +1 more source

A Search for Be Stars in Multiple Systems within the Solar Neighborhood

The Astrophysical Journal
Be stars are widely considered to be the product of binary interaction. However, whether all Be stars are formed via binary interaction is unclear, and detailed estimates of the multiplicity of Be stars and characterization of their components are ...
V. M. Kalari, R. Salinas, C. Sáez-Carvajal, R. D. Oudmaijer, S. Howell, S. Caballero-Nieves, K. Kamp, R. Matson, N. Scott, T. Cao, Z. Hartman, H. Kim   +11 more
doaj   +1 more source

A Dragon Out of Breath? Monitoring High-velocity Outflows from the High-mass Gamma-Ray Binary LS 2883/PSR B1259–63 During the 2017–2021 Binary Cycle

The Astrophysical Journal, 2023
Observations of the high-mass gamma-ray binary LS 2883/PSR B1259–63 with the Chandra X-ray Observatory during the 2011–2014 and 2014–2017 binary cycles have shown X-ray-emitting clumps, presumably ejected from the binary during periastron passages. These
Jeremy Hare, George G. Pavlov, Gordon P. Garmire, Oleg Kargaltsev   +3 more
doaj   +1 more source