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Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign
We present simultaneous and continuous observations of the Hα,Hβ, He I D3, Na I D1, D2 doubletand the Ca II H & K lines for the RS CVn system HR 1099. Thespectroscopic observations were obtained during the MUSICOS 1998campaign involving several observatories and instruments, both echelleand long-slit spectrographs. During this campaign, HR 1099 was observedalmost continuously for more than 8 orbits of 2.8 deg. Two large opticalflares were observed, both showing an increase in the emission ofHα, Ca II H & K, Hβ and He I D3 and a strongfilling-in of the Na I D1, D2 doublet.Contemporary photometric observations were carried out with the robotictelescopes APT-80 of Catania and Phoenix-25 of Fairborn Observatories.Maps of the distribution of the spotted regions on the photosphere ofthe binary components were derived using the Maximum Entropy andTikhonov photometric regularization criteria. Rotational modulation wasobserved in Hα and He I D3 in anti-correlation with thephotometric light curves. Both flares occurred at the same binary phase(0.85), suggesting that these events took place in the same activeregion. Simultaneous X-ray observations, performed by ASM on board RXTE,show several flare-like events, some of which correlate well with theobserved optical flares. Rotational modulation in the X-ray light curvehas been detected with minimum flux when the less active G5 V star wasin front. A possible periodicity in the X-ray flare-like events was alsofound.Based on observations obtained during the MUSICOS 98 MUlti-SIteCOntinuous Spectroscopic campaign from Observatoire de Haute-Provence,France, Kitt Peak National Observatory, USA, ESO La Silla, Chile, Mt.Stromlo Observatory, Australia, Xinglong National Observatory, China,Isaac Newton Telescope, Spain, Laboratório Nacional deAstrofísica, Brazil, and South African Astronomical Observatory,South Africa. Contemporaneous observations from Catania, Italy andFairborn Observatories, USA, and on data obtained with the Rossi X-rayTiming Explorer.
| Ca II H and K Filter Photometry on the UVBY System. II. The Catalog of Observations
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2828T&db_key=AST
| Evolved GK stars near the Sun. 2: The young disk population
From a sample of nearly 2000 GK giants a group of young disk stars withwell determined space motions has been selected. The zero point of theluminosity calibrations, both from the ultraviolet flux (modifiedStroemgren system) and that in the region of 4200 to 4900 A (DDOsystem), show a discontinuity of about a half magnitude at the border ofthe young disk and old disk domains. The population separation is basedon the space velocity components, which are also an age discriminant,with the population interface near 2 x 109 yr, based onmodels with convective overshoot at the core. This age corresponds togiant masses near 1.7 solar mass, near the critical mass separating theyoung stars that do not burn helium in degenerate cores from older starsthat do. Ten percent of both populations show CN anomalies in that thederived value of P(Fe/H) from CN (Cm) and fromFe(M1) differ by more than 0.1 dex and the weak and strong CNstars occur equally in the old disk but the weak CN stars predominate inthe young disk. Peculiar stars, where flux distortions affect theluminosity calibrations, are of the CH+(Ba II) and CH-(weak G band)variety and represent less than 1% of the stars in both populations. Theyoung disk giants are restricted to ages greater than about109 yr, because younger stars are bright giants orsupergiants (luminosity class 2 or 1), and younger than about 2 x109 yr, because the old disk-young disk boundary occurs near1.7 solar mass. The distribution of heavy element abundances, P(Fe/H),for young disk giants is both more limited in range (+/- 0.4 dex) and isskewed toward higher abundances, compared with the nearly normaldistribution for old disk giants. The distribution of (U,V) velocityvectors gives (U,V,W) and their dispersions = (+17.6 +/- 18.4, -14.8 +/-8.4, -6.9 +/- 13.0) and (+3.6 +/- 38.4, -20.7 +/- 27.5, -6.7 +/-17.3)km/s for young and old disk giants, respectively.
| Large and Kinematically Unbiased Samples of G- and K-Type Stars. III. Evolved Young Disk Stars in the Bright Star Sample
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989PASP..101...54E&db_key=AST
| Large and kinematically unbiased samples of G- and K-type stars. II - Observations of evolved stars in the Bright Star sample. III - Evolved young disk stars in the Bright Star sample
Four color and RI observations were obtained for a large sample ofG-type and K-type stars in the Bright Star Catalogue. Data are firstpresented for 110 evolved stars. Photometry of evolved young diskpopulation stars have then been calibrated for luminosity, reddening,and metallicity on the basis of results for members of the Hyades andSirius superclusters. New DDO results are given for 120 stars.
| MK classification for F- and G-type stars. IV
MK spectral classifications are given for 112 stars brighter than mv =7.5, having HD types F2-G5. The classifications were made on slitspectrograms of dispersion 75 A/mm at H gamma.
| Photoelectric Observations of V711 Tauri
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| Photoelectric radial velocities. V. 69 southern HR stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972MNRAS.155..449G&db_key=AST
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