Search Publications
Mass Ratios of Long-Period Binary Stars Resolved in Precision Astrometry Catalogs of Two Epochs
Makarov, V. V.
Mass ratios of widely separated, long-period, resolved binary stars can be directly estimated from the available data in major space astrometry catalogs, such as the ESA's Hipparcos and Gaia mission results. The method is based on the universal principle of inertial motion of the system's center of mass in the absence of external forces, and is in…
New Spectral Analysis Results Within the Scope of Extended Matter Research in the AR Lacertae Active Binary System
Ekmekçi, F.; Karakuş, O.
Within the scope of extended matter research, we present new spectral analysis results of an active binary system, AR Lac. The low and high resolution spectra of this system, were taken during the period 2013-2016. The evaluation of low dispersion spectra together with the B, V, Rc, Ic and WISE photometric data showed that AR…
Hα Kinematics of the Isolated Interacting Galaxy Pair KPG 486 (NGC 6090)
Rosado, M.; Sánchez-Cruces, M.; Sardaneta, M. M.
In optical images, the barely studied isolated interacting galaxy pair KPG 486 (NGC 6090) displays similar features to the Antennae (NGC 4038/39) galaxy pair. To compare the distribution of ionized hydrogen gas, morphology and kinematic and dynamic behaviour of both galaxy pairs, we present observations in the Hα emission line of NGC 6090 acquired…
Spectral Behavior of the Symbiotic Nova HM Sge in the Ultraviolet
Sanad, M. R.; Abdel-Sabour, M. A.
Ultraviolet observations of the symbiotic nova HM Sge were obtained from the International Ultraviolet Explorer (IUE) through the interval from 1980 - 1992. Three line profiles demonstrating the variations of some emission lines at different dates are presented. We determined the reddening of HM Sge from the 2200 Å absorption feature; the estimate…
Metallicity Gradients in M 31, M 33, NGC 300 and the Milky Way Using Abundances of Different Elements
Peña, M.; Flores-Durán, S. N.
Metallicity gradients derived from planetary nebulae (PNe) using O, Ne, and Ar abundances are studied and compared to those from H II regions in the galaxies M 31, M 33, NGC 300 and the Milky Way. Galactocentric radii and chemical abundances were collected from the literature, carefully selecting a homogeneous sample for each galaxy. Metallicity g…
NGC 1261: A Time-Series VI Study of its Variable Stars
Arellano Ferro, A.; Calderón, J. H.; Bustos Fierro, I. H. +1 more
Time-series VI CCD photometry of the globular cluster NGC 1261 is employed to study its variable star population. A membership analysis of most variables based on Gaia DR2 proper motions and colours was performed prior to the estimation of the mean cluster distance and metallicity. The light curves of the member RR Lyrae were Fourier decomposed to…
Millimeter and Far-IR Study of the IRDC SDC 341.232-0.268
Rubio, M.; Firpo, V.; Cappa, C. E. +3 more
We analyze the molecular gas and dust associated with the infrared dark cloud SDC 341.232-0.268 in order to investigate the characteristics and parameters of the gas, determine the evolutionary status of four embedded EGO candidates, and establish possible infall or outflow gas motions. We base our study on 12CO(2-1), 13CO(2-…
The HH34 Jet/Counterjet System at 1.5 and 4.5µm
Raga, A. C.; Noriega-Crespo, A.; Reipurth, B.
We present a (previously unpublished) 1.5 µm archival HST image of the HH 34 Herbig-Haro jet, in which the northern counterjet is seen at an unprecedented angular resolution of ≈0.1" (this counterjet had only been imaged previously at lower resolution with Spitzer). The jet/counterjet structure observed in this image shows evidence of low-am…
AGB Candidates in the Field of γ Cas1
Enke, H.; Nesci, R.; Tuvikene, T. +4 more
We report the spectroscopic and photometric monitoring of a sample of 530 candidate AGB stars in a 5×5 degrees field, selected from the IPHAS catalog; historic light curves were derived from Asiago IR plates taken in the years 1965-1984. We found 10 Miras, 5 stars with long term trends, 3 semiregular and 3 irregular. Spectral types from CCD slit s…
δ Mus Revisited: Rectifying a 82 yr-old Mistake
Boffin, Henri M. J.; Pourbaix, Dimitri
The red giant δ Muscae is known since 1919 to be a spectroscopic binary, and the first and only orbit was determined in 1936, claiming the period to be 847 days. This was discrepant with the Hipparcos determined astrometric orbit. Using the latest data available for this object - leading to a 100 yr time-span - we show here that the correct period…