Contents
Images
Upload your image
DSS Images Other Images
Related articles
Determining global parameters of the oscillations of solar-like stars
Context. Helioseismology has enabled us to better understand the solarinterior, while also allowing us to better constrain solar models. Butnow is a tremendous epoch for asteroseismology as space missionsdedicated to studying stellar oscillations have been launched within thelast years (MOST and CoRoT). CoRoT has already proved valuable resultsfor many types of stars, while Kepler, which was launched in March 2009,will provide us with a huge number of seismic data very soon. This is anopportunity to better constrain stellar models and to finally understandstellar structure and evolution. Aims: The goal of this researchwork is to estimate the global parameters of any solar-like oscillatingtarget in an automatic manner. We want to determine the globalparameters of the acoustic modes (large separation, range of excitedpressure modes, maximum amplitude, and its corresponding frequency),retrieve the surface rotation period of the star and use these resultsto estimate the global parameters of the star (radius and mass). Methods: To prepare for the arrival and the analysis of hundreds ofsolar-like oscillating stars, we have developed a robust and automaticpipeline, which was partially adapted from helioseismic methods. Thepipeline consists of data analysis techniques, such as Fast FourierTransform, wavelets, autocorrelation, as well as the application ofminimisation algorithms for stellar-modelling. Results: We applyour pipeline to some simulated lightcurves from the asteroFLAG team andthe Aarhus-asteroFLAG simulator, and obtain results that are consistentwith the input data to the simulations. Our strategy gives correctresults for stars with magnitudes below 11 with only a few 10% of baddeterminations among the reliable results. We then apply the pipeline tothe Sun and three CoRoT targets. In particular we determine the largeseparation and radius of the Sun, HD49933, HD181906, and HD181420.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| Late A-type stars: new Strömgren photometric calibrations of absolute magnitudes from HIPPARCOS
Hipparcos trigonometric parallaxes have been used to derive aphotometric absolute magnitude calibration of main-sequence late A-typestars in terms of Strömgren photometric indices - accounting fortemperature, evolution and metallicity effects - and projectedequatorial rotational velocities. The derived calibrations are valid formain-sequence normal A3-A9 and metallic Am stars, showing residuals of0.22 and 0.20 magnitudes, respectively. One of the fitting methods used(BCES) allows the derivation of the observational ZAMS in this spectralrange, showing an excellent accordance with theoretical evolutionarymodels. The evolutionary state of the Am stars is also discussed.Table~A1 is only available in electronic form from CDS via anonymous ftp130.79.128.5, and by e-mail: request to cesca@am.ub.es
| Miscellaneous spectroscopic notes
Results of slit-spectrograph observations are reported for approximately260 stars. The data presented range from recognition of many new Ap, Am,and other unusual stars to H-alpha observations of early-typesupergiants and Be stars. The material discussed was obtained over thepast 40 years at a number of U.S. observatories and at the DominionAstrophysical Observatory in Victoria, B.C.
| Properties of AM stars in the Geneva photometric system
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&A....92..289H&db_key=AST
| Catalogue of early-type stars measured in a narrow-band photometric system
A compilation of the photoelectric measurements in the Barbier-Morguleffsystem is presented. The catalogue includes data for 773 stars ofspectral type 08 to F6. 706 stars have been measured at least twice.
| Multicolor photometry of metallic-line stars. III. A photometric catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974RMxAA...1..175M&db_key=AST
| Catalogue et bibliographie des étoiles A à spectre particulier - Deuxième supplément
Not Available
| Catalogue et bibliographie des étoiles A à spectre particulier
Not Available
| A Catalog of Magnetic Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958ApJS....3..141B&db_key=AST
| A survey of stars with composite spectra.
Not Available
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Cygnus |
| Right ascension: | 20h07m53.19s |
| Declination: | +45°59'54.8" |
| Apparent magnitude: | 8.172 |
| Distance: | 1724.138 parsecs |
| Proper motion RA: | 9.1 |
| Proper motion Dec: | 16.1 |
| B-T magnitude: | 8.599 |
| V-T magnitude: | 8.208 |
Catalogs and designations:
|
