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Signal Synchronization Strategies and Time Domain SETI with Gaia DR3
Davenport, James R. A.; Siemion, Andrew P. V.; Croft, Steve +1 more
Spatiotemporal techniques for signal coordination with actively transmitting extraterrestrial civilizations, without the need for prior communication, can constrain technosignature searches to a significantly smaller coordinate space. With the variable star catalog from Gaia Data Release 3, we explore two related signaling strategies: the SETI Ell…
A Geologic Map of Vesta Produced Using a Hybrid Method for Incorporating Spectroscopic and Morphologic Data
Williams, David A.; Aileen Yingst, R.; Berman, Daniel C. +3 more
We have constructed a global geologic map of the minor planet Vesta at 1:300,000-scale using Dawn spacecraft imaging, spectroscopic, topographic, and elemental data. In this effort, we used a mapping method that requires creating two maps independently: the first map uses morphology and topography to define map units, while the second map relies o…
The SSA22 H I Tomography Survey (SSA22-HIT). I. Data Set and Compiled Redshift Catalog
Ouchi, Masami; Hennawi, Joseph F.; Inoue, Akio K. +16 more
We conducted a deep spectroscopic survey, named SSA22-HIT, in the SSA22 field with the DEep Imaging MultiObject Spectrograph (DEIMOS) on the Keck telescope, designed to tomographically map high-z H I gas through analysis of Lyα absorption in background galaxies' spectra. In total, 198 galaxies were spectroscopically confirmed at 2.5 < z < 6 …
Refining Orbits of Bright Binary Systems
Miroshnichenko, Anatoly S.; Danford, Stephen; Andronov, Ivan L. +3 more
We obtained spectra of several bright binary systems (ζ02 UMa, 2 Lac, and ϕ Aql), which were mostly observed with photographic plates and whose orbits were not determined very accurately. Each system was monitored for a few years with the 81-cm telescope equipped with an échelle spectrograph at the Three College Observatory in North Carolina. The …
Lower-ionosphere electron density and effective recombination coefficients from multi-instrument space observations and ground VLF measurements during solar flares
Dominique, Marie; Žigman, Vida; Grubor, Davorka +2 more
A new model to predict the electron density and effective recombination coefficient of the lower ionosphere under solar flare conditions is presented. This model relies on space-borne solar irradiance measurements in coincidence with ground recorded active transmissions of Very Low Frequency (VLF), (<30 kHz) signals. Use is made of the irradian…
The rotation period distribution in the young open cluster NGC 6709
Granzer, T.; Barnes, S. A.; Weingrill, J. +1 more
Open clusters serve as a useful tool for calibrating models of the relationship between mass, rotation, and age for stars with an outer convection zone due to the homogeneity of the stars within the cluster. Cluster-to-cluster comparisons are essential to determine whether the universality of spin-down relations holds.
Asteroseismic Determination of Stellar Rotation: On Synchronization in the Close Eclipsing Binaries AB Cas and OO Dra
Kim, Seung-Lee
A star's rotation rate is difficult to estimate without surface inhomogeneities such as dark or bright spots. This paper presents asteroseismic results to determine the rotation rates of δ Sct-type pulsating primary stars in two eclipsing binary systems, AB Cas and OO Dra. After removing the binarity-induced light variations from archival TESS dat…
Photometric variable stars in the young open cluster NGC 6823
Chen, W. P.; Bhatt, B. C.; Pandey, J. C. +8 more
We present stellar variability towards the young open cluster NGC 6823. Time series V- and I-band CCD photometry led to identification and characterization of 88 variable stars, of which only 14 have been previously recognized. We ascertain the membership of each variable with optical UBVI and infrared photometry, and with Gaia EDR3 parallax and p…
The source of electrons at comet 67P
Nilsson, H.; Goetz, C.; Henri, P. +8 more
We examine the origin of electrons in a weakly outgassing comet, using Rosetta mission data and a 3D collisional model of electrons at a comet. We have calculated a new data set of electron-impact ionization (EII) frequency throughout the Rosetta escort phase, with measurements of the Rosetta Plasma Consortium's Ion and Electron Sensor (RPC/IES). …
Solar active region magnetic parameters and their relationship with the properties of halo coronal mass ejections
Moon, Y. -J.; Shanmugaraju, A.; Ebenezer, E. +2 more
The coronal mass ejections (CMEs) from the sun consist of the plasma and strong magnetic fields (∼4-5 G at 1.3 R⊙) and generally, the fast CMEs are often associated with energetic particles of energy few hundreds of MeV. When the fast CMEs are ejected towards the Earth, they can disrupt the flow of solar wind in the heliosphere and impa…