اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدOptical spectroscopy of DPVs and the case of LP Ara
356
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We present preliminary results of our spectroscopic campaign of a group of intermediate mass interacting binaries dubbed Double Periodic Variables (DPVs), characterized by orbital light curves and additional long photometric cycles recurring roughly after 33 orbital periods (Mennickent et al. 2003, 2005). They have been interpreted as interacting, semi-detached binaries showing cycles of mass loss into the interstellar medium (Mennickent et al. 2008, Mennickent & Kolaczkowski 2009). High resolution Balmer and helium line profiles of DPVs can be interpreted in terms of mass flows in these systems. A system solution is given for LP Ara, based on modeling of the ASAS V-band orbital light curve and the radial velocity of the donor star.
قيم البحث
اقرأ أيضاً
Using the high-resolution near-infrared adaptive optics imaging from the NaCo instrument at the Very Large Telescope, we report the discovery of a new binary companion to the M-dwarf LP 1033-31 and also confirm the binarity of LP 877-72. We have char
acterised both the stellar systems and estimated the properties of their individual components. We have found that LP 1033-31 AB with the spectral type of M4.5+M4.5 has a projected separation of 6.7$pm$1.3 AU. Whereas with the spectral type of M1+M4, the projected separation of LP 877-72 AB is estimated to be 45.8$pm$0.3 AU. The binary companions of LP 1033-31 AB are found to have similar masses, radii, effective temperatures, and log $g$ with the estimated values of 0.20$pm$0.04 $rm{M}_{odot}$, 0.22$pm$0.03 $rm{R}_{odot}$, 3200 K, 5.06$pm$0.04. However, the primary of LP 877-72 AB is found to be twice as massive as the secondary with the derived mass of 0.520$pm$0.006 $rm{M}_{odot}$. The radius and log $g$ for the primary of LP 877-72 AB are found to be 1.8 and 0.95 times that of the secondary component with the estimated values of 0.492$pm$0.011 $rm{R}_{odot}$ and 4.768$pm$0.005, respectively. With an effective temperature of 3750$pm$15 K, the primary of LP 877-72 AB is also estimated to be $sim$400 K hotter than the secondary component. We have also estimated the orbital period of LP 1033-31 and LP 877-72 to be $sim$28 and $sim$349 yr, respectively. The binding energies for both systems are found to be $gt$10$^{43}$ erg, which signifies both systems are stable.
We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our $BVRI$ and $griz$ photometry covers 167 days of evolution, including the rise to the light curve maximum, and ends just after the beginning of
the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup, and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated via hydrodynamical modelling, yielding an explosion energy of $1$ foe, a pre-SN mass of $19,{rm M_{odot}}$, a progenitor radius as $30,{rm R_{odot}}$ and a $^{56}$Ni mass as $0.062,{rm M_{odot}}$. These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with slightly sub-solar metallicty.
New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system were taken through BVI filters from the Congarinni Observatory in Australia. The new ephemeris is calculated based
on seven new determined minimum times, together with the TESS data and others compiled from the literature. Photometric solutions determined by the Wilson-Devinney (W-D) code are combined with the Monte Carlo simulation to determine the adjustable parameters uncertainties. These solutions suggest that V870 Ara is a contact binary system with a mass ratio of 0.082, a fillout factor of 96+-4 percent, and an inclination of 73.60+-0.64 degrees. The absolute parameters of V870 Ara were determined by combining the Gaia EDR3 parallax and photometric elements.
We present low-resolution phase-resolved spectra of the polar MT Dra during its high states in 2006 and 2009. Balmer series, He I and He II 4686 AA emission lines have complex shapes and show similar profile variations over an orbital cycle. The radi
al velocities vary with orbital period and display motions of the gas falling close to the magnetic poles of the white dwarf.
The thiophenoxy radical (C6H5S) is a species of possible astrophysical interest due to an electronic transition in a 5000 A region. The B <-- X electronic transition of this radical in the discharge of thiophenol was measured using a cavity ring-down
spectrometer. The optical absorption spectrum of this transition was obtained in the range covering from the origin band (0-0) to a frequency of 1750 cm-1. The vibronic bands in the 400-1700 cm-1 region are stronger than the origin band, suggesting structural difference between the ground and excited electronic states. The prominent progression was assigned to the 6a symmetric in-plane CCC bending mode starting from the 6b10 forbidden band. Band origins of individual bands were determined by analysis of the rotational profiles. Although these vibronic bands were not found in optical spectra of diffuse clouds, the upper limits of the column densities for the thiophenoxy radical in the diffuse clouds toward HD 183143 and HD 204827 were evaluated to be 4 x 10^13 cm-2.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
