77 research outputs found
Discovery and analysis of p-mode and g-mode oscillations in the A-type primary of the eccentric binary HD 209295
We have discovered both intermediate-order gravity mode and low-order
pressure mode pulsation in the same star, HD 209295. It is therefore both a
Gamma Doradus and a Delta Scuti star, which makes it the first pulsating star
to be a member of two classes.
The star is a single-lined spectroscopic binary with an orbital period of
3.10575 d and an eccentricity of 0.352. Weak pulsational signals are found in
both the radial velocity and line-profile variations, allowing us to show that
the two highest-amplitude Gamma Doradus pulsation modes are consistent with l=1
and |m|=1.
In our 280 h of BVI multi-site photometry we detected ten frequencies in the
light variations, one in the Delta Scuti regime and nine in the Gamma Doradus
domain. Five of the Gamma Doradus frequencies are exact integer multiples of
the orbital frequency. This observation leads us to suspect they are tidally
excited. Results of theoretical modeling (stability analysis, tidal excitation)
were consistent with the observations.
We could not detect the secondary component of the system in infrared
photometry, suggesting that it may not be a main-sequence star. Archival data
of HD 209295 show a strong ultraviolet excess, the origin of which is not
known. The orbit of the primary is consistent with a secondary mass of M > 1.04
Msun indicative of a neutron star or a white dwarf companion.Comment: 18 pages, 18 figures, accepted for publication in MNRAS, shortened
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Gravitational Waves from Gravitational Collapse
Gravitational wave emission from the gravitational collapse of massive stars
has been studied for more than three decades. Current state of the art
numerical investigations of collapse include those that use progenitors with
realistic angular momentum profiles, properly treat microphysics issues,
account for general relativity, and examine non--axisymmetric effects in three
dimensions. Such simulations predict that gravitational waves from various
phenomena associated with gravitational collapse could be detectable with
advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for
publication in Living Reviews in Relativity (http://www.livingreviews.org
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Fatigue Life of Friction Stir Welded Joints in the Presence of Corrosion Damage: Experiments and Calculations
The Ring Nebula, NGC 6720
THE NORTH DAKOTA SPACE GRANT CONSORTIUM COLLECTION
NASA initiated the National Space Grant College and Fellowship Program, also known as Space Grant, in 1989. This national network of colleges and universities works to expand opportunities for Americans to understand and participate in NASA\u27s aeronautics and space projects by supporting and enhancing science and engineering education, research, and public engagement efforts.
The North Dakota NASA Space Grant Consortium (NDSGC) was established in February of 1991. The North Dakota NASA Space Grant Consortium fulfills the Space Grant mission by involving North Dakota faculty, students, and K‐12 teachers and students in multi‐institutional, collaborative, NASA‐relevant research and education projects, while also educating the North Dakota citizenry about NASA, its purpose, and its missions.
The North Dakota Space Grant Consortium has a collection of printed posters, photos, and art available to the public. Pieces can be collected at the North Dakota Space Grant Consortium office (Clifford Hall, Room 270) on the UND campus.
Image text: National Aeronautics and Space Administration NASA The Ring Nebula, NGC 6720https://commons.und.edu/ndsgc-posters/1040/thumbnail.jp
Interacting Galaxies Arp 273
THE NORTH DAKOTA SPACE GRANT CONSORTIUM COLLECTION
NASA initiated the National Space Grant College and Fellowship Program, also known as Space Grant, in 1989. This national network of colleges and universities works to expand opportunities for Americans to understand and participate in NASA\u27s aeronautics and space projects by supporting and enhancing science and engineering education, research, and public engagement efforts.
The North Dakota NASA Space Grant Consortium (NDSGC) was established in February of 1991. The North Dakota NASA Space Grant Consortium fulfills the Space Grant mission by involving North Dakota faculty, students, and K‐12 teachers and students in multi‐institutional, collaborative, NASA‐relevant research and education projects, while also educating the North Dakota citizenry about NASA, its purpose, and its missions.
The North Dakota Space Grant Consortium has a collection of printed posters, photos, and art available to the public. Pieces can be collected at the North Dakota Space Grant Consortium office (Clifford Hall, Room 270) on the UND campus.
Image text: Interacting Galaxies Arp 273 National Aeronautics and Space Administration NASAhttps://commons.und.edu/ndsgc-posters/1023/thumbnail.jp
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