Astrometry and Spectroscopy as Tools Toward Visual-Binary Masses

1992 ◽  
Vol 135 ◽  
pp. 273-275
Author(s):  
W.D. Heintz
Keyword(s):  
High Precision ◽  
Main Sequence ◽  
Mass Determination ◽  
Orbital Elements ◽  
High Quality ◽  
Visual Binary ◽  
Mass Ratios ◽  
The Status ◽  
Sequence Components

Following the diversified topic of this conference, let me present a variety of comments — not all new, but resulting from a long string of stars drifting across the desk. The chase after visual orbital elements is not exactly a self-purpose but is aiming at further data, in particular, at good masses. The last published lists of high-quality mass determination represent the status of 20 years ago; but a compilation at this time would probably not last long as the progress promises to quicken.We have 1000 positional (visual/photographic/speckle) orbits, among them about 700 acceptable in the range from fair to definitive. Yet less than 10% of them give good component masses. Most of them are outside the range of parallax measures with the requisite, high precision (that unfortunatly holds for the Hyades); some frustrate the parallax measurer by displaying wedge– and peanut–shaped images, and the more exciting cases of abnormal, non-main–sequence components often cannot get good mass ratios owing to large distances or long periods.

scholarly journals Absolute properties of RU Cnc revisited: an active RS CVn-type eclipsing binary with red giant branch and main-sequence components

2019 ◽  
Vol 488 (4) ◽  
pp. 4520-4525 ◽  
Author(s):  
K A Çokluk ◽  
D Koçak ◽  
T İçli ◽  
S Karaköse ◽  
S Üstündağ ◽  
...  
Keyword(s):  
Main Sequence ◽  
Variation Analysis ◽  
High Quality ◽  
Eclipsing Binary ◽  
Data Release ◽  
Sequence Components ◽  
Red Giant ◽  
Period Decrease ◽  
The Masses

ABSTRACT We present observations and analysis of an RS CVn-type double-lined eclipsing binary system, RU Cnc. The system has been observed for over a century. High-quality long-cadence observations, newly obtained from the Kepler K2 C5 and C18 campaigns, and two radial velocity curves were combined and analysed simultaneously, assuming a multispot model. The masses, radii and luminosities of the component stars have been precisely obtained as $M_\textrm{c} = 1.386\pm 0.044\, \mathrm{M}_{\odot }$, $M_\textrm{h} = 1.437 \pm 0.046\, \mathrm{M}_{\odot }$, $R_\textrm{h} = 2.39\pm 0.07\, \mathrm{R}_{\odot }$, $R_\textrm{c} = 5.02 \pm 0.08\, \mathrm{R}_{\odot }$, $L_\textrm{h} = 11.4\pm 1.2\, \mathrm{L}_{\odot }$ and$L_\textrm{c} = 12.0 \pm 1.0\, \mathrm{L}_{\odot }$, with a separation of $a = 27.914 \pm 0.016\, \mathrm{R}_{\odot }$. The distance of the system is determined to be $380\pm 57\,$ pc, which is consistent with the Gaia Data Release 2 result. Long-term detailed period variation analysis of the system indicates a period decrease of 7.9 × 10−7 d yr–1. The results suggest that the cooler component is on the red giant branch (RGB) and the hotter component is still on the main sequence.

scholarly journals On the component masses of visual binaries

2010 ◽  
pp. 71-80 ◽  
Author(s):  
Zorica Cvetkovic ◽  
S. Ninkovic
Keyword(s):  
Binary Stars ◽  
Total Mass ◽  
Input Data ◽  
Main Sequence ◽  
Clear Indication ◽  
Orbital Elements ◽  
High Quality ◽  
Large Dispersion ◽  
Visual Binary Stars ◽  
Visual Binaries

In the Sixth Catalog of Orbits of Visual Binary Stars we found those belonging to the Main Sequence to form a sample containing 432 visual binaries. Their total masses were obtained dynamically, i.e. they were calculated using the orbital elements and the new Hipparcos parallaxes. For the same pairs the total mass was also found astrophysically - by applying the mass-luminosity relation. The apparent magnitudes of the components were found in two different ways: by deriving them from total magnitudes and magnitude differences, and by taking their values directly from a catalogue. The results for these two approaches show no essential discrepancy. The values of total masses obtained dynamically have a large dispersion involving even completely unrealistic values. This is a clear indication that the input data are not sufficiently reliable. Nevertheless, in a large number of cases the agreement between total masses obtained by us in two different ways is quite satisfactory indicating that i) for many visual binaries, as a rule not too distant and with high-quality orbital elements, the dynamical total masses can be reliable; ii) the mass-luminosity relation yields quite satisfactory estimates for the component masses when they belong to the Main Sequence and iii) a correlation between the relative parallax error and orbit grade exists.

UKP-laserbasierte Herstellung von Netzen unterschiedlicher Transmissionsgrade/USP-laser based production of meshes of different transmission degrees

2020 ◽  
Vol 110 (11-12) ◽  
pp. 787-789
Author(s):  
Marcel Simons ◽  
Till Rusche ◽  
Tobias Valentino ◽  
Tim Radel ◽  
Frank Vollertsen
Keyword(s):  
High Precision ◽  
Processing Speed ◽  
Laser Processing ◽  
Short Pulse ◽  
High Quality ◽  
Mesh Width ◽  
Variable Transmission ◽  
Ultra Short Pulse ◽  
Mesh Structures

Die Ultrakurzpuls (UKP)-laserbasierte Bearbeitung erlaubt die Herstellung von Netzstrukturen mit verschiedenen Transmissionsgraden. Vorteile der UKP-laserbasierten Herstellung der Netze liegen vor allem in der hohen Präzision und Bearbeitungsgeschwindigkeit. Die UKP-Laserbearbeitung ermöglicht die Herstellung von Netzen aus Aluminium in hoher Qualität, bezogen auf die Stegbreitenabweichung von < 8 µm, mit variablen Transmissionsgraden. Ultra-short pulse (USP) laser based processing enables the production of mesh structures with different degrees of transmission. The advantages of USP-based production of mesh structures are mainly the high precision and processing speed. USP laser processing enables the production of meshes of aluminum in high quality, with respect to the mesh width deviation of < 8 µm with variable transmission degrees.

scholarly journals Lyell, the Geikies and Croll's observations on terrestrial glacial sediments and landforms

2021 ◽  
pp. 1-14
Author(s):  
James ROSE
Keyword(s):  
Climate Change ◽  
High Quality ◽  
Glacial Sediments ◽  
Direct Observations ◽  
The Social ◽  
The Status ◽  
Social And Physical Environment ◽  
Glacial Landforms

ABSTRACT Within the context of the work and achievements of James Croll, this paper reviews the records of direct observations of glacial landforms and sediments made by Charles Lyell, Archibald and James Geikie and James Croll himself, in order to evaluate their contributions to the sciences of glacial geology and Quaternary environmental change. The paper outlines the social and physical environment of Croll's youth and contrasts this with the status and experiences of Lyell and the Geikies. It also outlines the character and role of the ‘Glasgow School’ of geologists, who stimulated Croll's interest into the causes of climate change and directed his focus to the glacial and ‘interglacial’ deposits of central Scotland. Contributions are outlined in chronological order, drawing attention to: (i) Lyell's high-quality observations and interpretations of glacial features in Glen Clova and Strathmore and his subsequent rejection of the glacial theory in favour of processes attributed to floating icebergs; (ii) the significant impact of Archibald Geikie's 1863 paper on the ‘glacial drift of Scotland’, which firmly established the land-ice theory; (iii) the fact that, despite James Croll's inherent dislike of geology and fieldwork, he provided high-quality descriptions and interpretations of the landforms and sediments of central Scotland in order to test his theory of climate change; and (iv) the great communication skills of James Geikie, enhanced by contacts and evidence from around the world. It is concluded that whilst direct observations of glacial landforms and sediments were critical to the long-term development of the study of glaciation, the acceptance of this theory was dependent also upon the skills, personality and status of the Geikies and Croll, who developed and promoted the concepts. Sadly, the subsequent rejection of the land-ice concept by Lyell resulted in the same factors challenging the acceptance of the glacial theory.

scholarly journals Immune Checkpoint Inhibitors in Urothelial Carcinoma: Recommendations for Practical Approaches to PD-L1 and Other Potential Predictive Biomarker Testing

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1424
Author(s):  
Antonio Lopez-Beltran ◽  
Fernando López-Rios ◽  
Rodolfo Montironi ◽  
Sophie Wildsmith ◽  
Markus Eckstein
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Best Practice ◽  
Checkpoint Inhibitors ◽  
Predictive Biomarker ◽  
High Quality ◽  
The Status ◽  
Biomarker Testing ◽  
Novel Biomarkers ◽  
Scoring Algorithms

Immuno-oncology (IO) agents (anti–programmed cell death 1 (PD-1) and anti–programmed cell death-ligand 1 (PD-L1)) are approved as first- and second-line treatments for metastatic UC. PD-L1 expression levels in UC tumors help clinicians determine which patients are more likely to respond to IO therapies. Assays for approved IO agents use different antibodies, immunohistochemical protocols, cutoffs (defining “high” vs. “low” PD-L1 expression), and scoring algorithms. The robust control of pre-analytical and analytical standards is needed to obtain high-quality PD-L1 results. To better understand the status and perspectives of biomarker-guided patient selection for anti–PD-1 and anti–PD-L1 agents in UC, three workshops were held from December 2018 to December 2019 in Italy, Malaysia, and Spain. The primary goal was to develop recommendations for best practice approaches to PD-L1 testing in UC. Recommendations pertaining to the interpretation and reporting of the results of PD-L1 assays from experienced pathologists and oncologists from around the globe are included. A test request form for pathology laboratories was developed as a critical first step for oncologists/urologists to encourage communication between clinicians and pathologists, ensuring fast and high-quality test results. In this era of personalized medicine, we briefly discuss novel biomarkers being evaluated for IO agents in UC.

The Current Status of Hearing Care: Can We Change the Status Quo?

2005 ◽  
Vol 16 (07) ◽  
pp. 410-418 ◽  
Author(s):  
Dennis Van Vliet
Keyword(s):  
United States ◽  
Hearing Loss ◽  
Care Delivery ◽  
The United States ◽  
Status Quo ◽  
Hearing Impaired ◽  
Current Status ◽  
High Quality ◽  
Scientific Database ◽  
The Status

The members of the profession of audiology often express concern that the services and products that have been developed to provide benefit to the hearing impaired are not sought after or delivered to the majority of those diagnosed with hearing loss. A critical look at the status quo of hearing care delivery in the United States is needed to verify this assumption and to develop strategies to improve the situation. A key concern is the lack of a comprehensive high-quality scientific database upon which to build continuous improvements in the effectiveness of the services and products that are provided to the hearing impaired.

LASER-ELECTRON PHOTON PROJECT AT SPRING-8

2003 ◽  
Vol 18 (02n06) ◽  
pp. 208-214
Author(s):  
◽  
T. NAKANO
Keyword(s):  
Compton Scattering ◽  
Maximum Energy ◽  
Photon Beam ◽  
High Quality ◽  
Hadron Physics ◽  
Preliminary Results ◽  
The Status ◽  
Electron Photon ◽  
New Facility

The GeV photon beam at SPring-8 is produced by backward-Compton scattering of laser photons from 8 GeV electrons. Polarization of the photon beam will be ~100% at the maximum energy with fully polarized laser photons. We report the status of the new facility and the prospect of hadron physics study with this high quality beam. Preliminary results from the first physics run are presented.

High-precision abundances of elements in stars with asteroseismic ages

2017 ◽  
Vol 13 (S334) ◽  
pp. 166-169
Author(s):  
P. E. Nissen ◽  
V. Silva Aguirre ◽  
J. Christensen-Dalsgaard ◽  
R. Collet ◽  
F. Grundahl ◽  
...  
Keyword(s):  
High Precision ◽  
Main Sequence ◽  
Potential Problem ◽  
Galactic Evolution ◽  
The Other ◽  
Main Sequence Stars ◽  
Refractory Elements ◽  
Other Hand ◽  
New Information ◽  
Oscillation Frequencies

AbstractHigh-precision abundances of elements have been derived from HARPS-N spectra of F and G main-sequence stars having ages determined from oscillation frequencies delivered by the Kepler mission. The tight relations between abundance ratios of refractory elements, e.g., [Mg/Fe] and [Y/Mg], and stellar age previously found for solar twin stars are confirmed. These relations provide new information on nucleosynthesis and Galactic evolution. Abundance ratios between volatile and refractory elements, e.g., [C/Fe] and [O/Fe], show on the other hand a significant scatter at a given age, which may be related to planet-star interactions. This is a potential problem for chemical tagging studies.

scholarly journals The Delta Scuti Network: Steps Towards Successful Asteroseismology of Delta Scuti Stars

2002 ◽  
Vol 185 ◽  
pp. 598-599
Author(s):  
W. Zima ◽  
M. Breger ◽  
K. Bischof ◽  
F. Rodler ◽  
A. Stankov ◽  
...  
Keyword(s):  
High Precision ◽  
Main Sequence ◽  
Scientific Research ◽  
Mode Identification ◽  
Short Period ◽  
Delta Scuti ◽  
The Moment ◽  
Identification Techniques ◽  
Scuti Stars ◽  
Nonradial Oscillations

AbstractThe Delta Scuti Network (DSN) is a collaboration of astronomers all around the globe who study and observe short-period variables. The field of scientific research includes high-precision photometric and Spectroscopic global campaigns, mode identification techniques, and asteroseismological pulsation modeling. We present results for three stars that are receiving the most attention at the moment: 4 CVn, BI CMi, and 44 Tau. Our results demonstrate that a large number of simultaneously excited nonradial oscillations in stars on and above the main sequence can be detected by conventional means.

Sign in / Sign up

Export Citation Format

Share Document