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Photometry of Star Clusters in the M 31 Galaxy. Aperture Size Effects
Narbutis, D.; Vansevičius, V.; Kodaira, K. +2 more
A study of aperture size effects on star cluster photometry in crowded fields is presented. Tests were performed on a sample of 285 star cluster candidates in the South-West field of the M 31 galaxy disk, measured in the Local Group Galaxy Survey mosaic images (Massey et al. 2006). In the majority of cases the derived UBVRI photometry errors repre…
Dust Distribution in [WR] Planetary Nebulae: a Case of M2-43
Szczerba, R.; Hajduk, M.; Gesicki, K.
Simultaneous presence of O- and C-rich molecules and/or dust is commonly known as mixed or dual chemistry. C-rich [WR] central stars show at the same time the presence of polycyclic aromatic hydrocarbons (PAHs) and crystalline silicates in their nebulae. We perform radiative transfer modeling of ISO spectrum for M2-43 to determine spatial location…
Eclipse Mapping of Symbiotic Binaries
Crowley, C.; Espey, B.
We describe an ultraviolet eclipse mapping of the symbiotic binary EG And. Analysis of FUSE and HST/STIS observations at differing orbital phases probe different layers of the chromosphere and wind of the red giant in absorption. Whilst the primary aim of the study is to examine the thermal and dynamic conditions at the base of these winds, much i…
New Insights Into the Dynamics and Expansion Parallax of Nebulae around Symbiotic Stars
Corradi, R. L. M.; Santander-García, M.
Currently, there are a dozen known spatially resolved nebulae around symbiotic stars. We summarize their properties, focusing on their dynamical ones. Then, new results about the determination of the expansion in the plane of the sky of the nebulae around Hen 2-104 and Hen 2-147, which allows us to gain important information about their dynamics a…
Period Change, Spot Migration and Orbital Solution for the Eclipsing Binary AR Lac
Munari, U.; Siviero, A.; Dallaporta, S.
We present a new large set of photoelectric photometric measurements (1806 in V and 1367 in B passbands) of the eclipsing RS CVn-type system AR Lac covering the period 2000 June 28 to 2005 October 13. 13 new epochs of minima have been derived that allows us to update the complex O--C pattern of this binary, now monitored for more than a hundred ye…
Helium, Carbon and Silicon Abundances in the HW VIR Eclipsing Binary Subdwarf-B Primary
Lynas-Gray, A. E.; Mortimore, A. N.
Light curve solutions show HW Vir and PG 1336-018 to be remarkably similar eclipsing binaries. The subdwarf-B (sdB) primary of PG 1336-018 is a pulsator but pulsation is not detected in the sdB primary of HW Vir. Ultraviolet spectra were used to obtain carbon and silicon abundances in the sdB primary of HW Vir; in due course these should be compar…
Radial Velocities of Population II Binary Stars. Ii.
Bartkevičius, A.; Sperauskas, J.
Here we publish the second list of radial velocities for 91 Hipparcos stars, mostly high transverse velocity binaries without previous radial velocity measurements. The measurements of radial velocities are done with a CORAVEL-type radial velocity spectrometer with an accuracy better than 1 km/s. We also present the information on eight new radial…
The Collective UV Behavior of Old Novae
Selvelli, P.
The UV spectral properties of 18 old-novae observed with IUE are examined. The de-reddened continuum energy distribution is well described by either a power-law distribution Fλ ∼λ -α with α in the range 0.3--2.5 or by a single black-body distribution with T in the range 15 000--38 000 K. The new values of EB-V ha…
The Transition from Outburst to Low Level Activity in the Low-Mass X-Ray Binary SAX J1747.0-2853
Ubertini, P.; Bazzano, A.; Heise, J. +6 more
SAX J1747.0-2853 is an X-ray transient which exhibited several outbursts between 1998 and 2001 and most probably in 1976. The outburst of 2000 was the longest and brightest. We have analyzed X-ray data sets that focus on times around the 2000 outburst and were obtained with l BeppoSAX, XMM-Newton and l RXTE.
Hst/stis Observations of Rotation of T Tauri Jets
Ray, T. P.; Eislöffel, J.; Bacciotti, F. +2 more
We report on observations of jets from T Tauri stars with the STIS spectrograph on board of the Hubble Space Telescope (HST). Observations of this kind can resolve structures to within 10--20 AU from the source and thus open the best observational window to the initial generation of jets that is available today. In particular, we can search for in…