Results 51 to 60 of about 6,728 (225)

Globally Critical Infrastructure: The Unique Risks and Challenges

Risk Analysis, Volume 45, Issue 12, Page 4804-4817, December 2025.
ABSTRACT Critical infrastructure is typically identified at the national level. However, disruption to certain infrastructure systems, facilities, and assets can have negative consequences for global societies. Such globally critical infrastructure entails a distinct risk profile for both countries dependent on the infrastructure, and countries that ...
Zachary Kallenborn, Henry H. Willis
wiley   +1 more source

JWST Imaging of the Closest Globular Clusters—VI. The Lowest‐Mass Objects in M 4 and the Galactic Bulge

Astronomische Nachrichten, Volume 346, Issue 9, November 2025.
ABSTRACT We present James Webb Space Telescope observations of M 4—the closest globular cluster—that probe the lower Main Sequence down to the hydrogen‐burning limit. The unveiled stellar sequence reaches much fainter luminosities than previously possible, revealing a few extremely red objects that are consistent with brown dwarfs as cool as Teff∼1000K$
L. R. Bedin, R. Gerasimov, A. Calamida, M. Libralato, M. Scalco, D. Nardiello, M. Griggio, D. Apai, J. Anderson, A. Bellini, A. Burgasser   +10 more
wiley   +1 more source

Integration of Statistical Models and Deep Learning: A CEEMDAN‐Based Hybrid Framework for Frequency‐Domain Prediction of Polar Motion

Earth and Space Science, Volume 12, Issue 10, October 2025.
Abstract High‐precision Earth Rotation Parameter (ERP) products often experience delays that range from several days to weeks. The use of precise forecasting models can effectively compensate for the impact of such delays. Based on a systematic analysis of the forecasting capabilities of the traditional harmonic least squares fitting and autoregressive
Chen Ren, Chen Wang, Zhenhong Li, Haoran Gong, Jialiang Liu   +4 more
wiley   +1 more source

COMMISSION 8: ASTROMETRY [PDF]

Proceedings of the International Astronomical Union, 2011
Gaia is continuing well with its development and construction and is expected to achieve parallax accuracies of about 10 to 300 μas for 6 to 20 mag. It is scheduled to launch in 2013. The ICRF2 was adopted by the IAU in 2009 as the new fundamental celestial reference frame.
Evans, Dafydd W., Zacharias, Norbert, Kumkova, Irina, Andrei, Alexandre Humberto, Brown, Anthony, Gouda, Naoteru, Popescu, Petre, Souchay, Jean, Unwin, Stephen C., Zhu, Z.   +9 more
openaire   +2 more sources

Reassessing the Relationship Between Meteor Radio Afterglows and Optical Persistent Trains

Journal of Geophysical Research: Space Physics, Volume 130, Issue 9, September 2025.
Abstract Meteor radio afterglows (MRAs) and optical persistent trains (PTs) are two types of long‐lived phenomena which are occasionally observed following the occurrence of a meteor. Both phenomena are thought to be produced by intrinsic emission mechanisms; PTs have been associated with chemiluminescent reactions between meteoric metals and ...
L. E. Cordonnier, K. S. Obenberger, G. B. Taylor, J. M. Holmes, J. Dowell, D. Vida   +5 more
wiley   +1 more source

The GAPS programme at TNG

Astronomy & Astrophysics
Context. The transition regime between giant planets (GPs) and brown dwarfs (BDs) is still an open subject of study in exoplanetary science. A complete understanding of the population of long-period GPs and BDs would be pivotal for improving our ...
Pinamonti M., Sozzetti A., Barbato D., Desidera S., Biazzo K., Bonomo A. S., Lanza A. F., Naponiello L., Affer L., Anche R. M., Andreuzzi G., Basilicata M., Brinjikji M., Brogi M., Cabona L., Carolo E., Colombo S., Damasso M., D’Arpa M., Di Filippo S., Harutyunyan A., Hom J., Mancini L., Mantovan G., Nardiello D., Santhakumari K. K. R., Zingales T.   +26 more
doaj   +1 more source

Halometry from astrometry [PDF]

Journal of Cosmology and Astroparticle Physics, 2018
Halometry---mapping out the spectrum, location, and kinematics of nonluminous structures inside the Galactic halo---can be realized via variable weak gravitational lensing of the apparent motions of stars and other luminous background sources. Modern astrometric surveys provide unprecedented positional precision along with a leap in the number of ...
Van Tilburg, Ken, Taki, Anna-Maria, Weiner, Neal   +2 more
openaire   +2 more sources

Improved astrometry for the Bohannan & Epps catalogue

, 2012
Aims. Accurate astrometry is required to reliably cross-match 20th-century catalogues against 21st-century surveys. The present work aims to provide such astrometry for the 625 entries of the Bohannan & Epps (1974, A&AS, 18, 47; BE74) catalogue of Hα ...
I. D. Howarth
core   +1 more source

Constraining the size, shape, and albedo of the large trans-Neptunian object (28978) Ixion with multi-chord stellar occultations

Astronomy & Astrophysics
Context. Trans-Neptunian objects (TNOs) are among the most primitive remnants of the early Solar System. Determining their sizes, shapes, albedos, and surface properties is essential for understanding their origin and evolution.
Kilic Y., Braga-Ribas F., Pereira C. L., Ortiz J. L., Sicardy B., Santos-Sanz P., Erece O., Rizos J. L., Gómez-Limón J. M., Margoti G., Souami D., Morgado B., Gomes-Junior A., Catani L. M., Desmars J., Kretlow M., Rommel F., Duffard R., Alvarez-Candal A., Camargo J. I. B., Kaplan M., Morales N., Herald D., Assafin M., Benedetti-Rossi G., Sfair R., Savalle R., Arcas-Silva J., Bernasconi L., Blank T., Bonavita M., Carlson N., Christophe B., Colesanti C. A., Collins M., Columba G., Dunford R., Dunham D. W., Dunham J., Emilio M., Ferrante W. G., George T., Hanna W., Isopi G., Jones R., Kenyon D. A., Kerr S., Kouprianov V., Maley P. D., Mallia F., Mattei J., Meunier M., Napoleao T., Peixoto V. F., Pollock J., Snodgrass C., Stechina A., Thomas W., Venable R., Viscome G. R., Zapparata A., Bardecker J., Castro N., Cebral C., Chapman A., Gao C., Green K., Guimaraes A., Jacques C., Jehin E., Konishi M., Leiva R., Liberato L., Magliano C., Mammana L. A., Melita M., Moura V., Olivera-Cuello Y., Peiro L., Spagnotto J., Stuart P. C., Vanzi L., Wilberger A., Malacarne M.   +83 more
doaj   +1 more source

Connecting VLBI and Gaia celestial reference frames

Frontiers in Astronomy and Space Sciences, 2016
The current state of the link problem between radio and optical celestial reference frames is considered.The main objectives of the investigations in this direction during the next few years are the preparation of a comparisonand the mutual orientation ...
Zinovy Malkin
doaj   +1 more source