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1.
We thank Dr. Dave Green (MRAO, UK) for one comment and one identified problem in our paper. The comment is that we did not discuss selection effects of the current sample of supernova remnants, which can be found in Case & Bhattacharya (1998) and Green (2004). The problem is the mis-usage of some SNR distances in Gusienov et al. (2003) and other references which were obtained from the assumed ∑-D relation. We mixed them to other data to derive the SNR diameters and SNR luminosity for statistics. This seriously affects the discussions in Section 3.3 and Figures 3 and 4. We cleaned out the flawed data and revise this part of the paper in the electronic version at http://www. chjaa.org.  相似文献   

2.
The light curve solutions of two W UMa binary systems in the intermediate open cluster NGC 7789 are presented in this paper. These variables were observed using the 2 m telescope of the IUCAA-Girawali Observatory. The V passband photo-metric solutions of the two W UMa binaries were obtained using the latest version of the W–D program. The result shows that both systems are H-subtype W UMa binaries with high mass ratios.  相似文献   

3.
We show that the recently observed 3.3 μm emission feature in the diffuse radiation from the galactic disk might be due to an ensemble of aromatic molecules distributed within very small interstellar grains. The same particles also provide an explanation of the λ2200 ? interstellar absorption feature. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

4.
The multicolor photometric observations of the neglected eclipsing binary FT Ursae Majoris (FT UMa) were obtained in 2010. The 2003 version of the Wilson-Devinney code was used to analyze the light curves in the B, V and R bands simultaneously. Based on the spectroscopic mass ratio q = 0.984 published by Pribulla et al., it is found that FT UMa is an evolved contact binary with a contact degree of 15.3%. The low amplitude of light variations, ～ 0.15 mag, arises mainly from a moderately low inclination angle...  相似文献   

5.
CCD photometric observations of the eclipsing binary PS Persei (PS Per) were obtained on two consecutive days in 2009.The 2003 version of the WilsonDevinney code was used to analyze the first complete light curves in the V and R bands.It is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche lobe.The mass ratio of q=0.518 and the orbital inclination of i=89.86° are obtained.In addition,based on all available times of primary light...  相似文献   

6.
We present an atlas of a group of bright stars in the range of spectral classes F-G and luminosity classes I-V. The spectra were obtained with spectral resolution R ～ 15 000 within spectral region 4500-6620/A Typical spectra of stars with different metallicity [Fe/H] are included. We also show the digital version of the spectral data in FITS format.  相似文献   

7.
An overview is given of the PAH and crystalline silicate emissions seen in the SWS guaranteed-time programme on planetary nebulae. Of the 9 objects on which good continuum measurements were obtained above 29 μm, 7 show evidence of olivine emission at 33.5 μm. PAH emission is seen in 5 of these objects, 3 objects show both PAH's and olivines. The presence of both types of features in a single object points to separate carbon-rich and oxygen-rich episodes of mass ejection. The spectrum of the nebula NGC 6302 shows a wealth of features in the range between 20 and 45 μm, many of which can be identified with olivines or pyroxenes. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

8.
We present the light curve and photometric solutions of the contact binary AD Cnc. The light curve appears to exhibit a typical O'Connell effect, with Maximum I brighter than Maximum II by 0.010 mag. in V. From 1987 to 2000, the light curve showed changes of shape: the depth of the primary eclipse increased by about 0.056m while that of the secondary eclipse decreased by about 0.032m, so the difference between the primary and the secondary eclipses increased by about 0.088m, while there was no obvious variation in the O'Connell effect. Using the present and past times of minimum light, the changes in the orbital period of the system are analyzed. The result reveals that the orbital period of AD Cnc has continuously increased at a rate of dp/dt = 4.4 ×10-7day yr-1. The light curve is analyzed by means of the latest version of the Wilson-Devinney code. The results show that AD Cnc is a W-subtype contact binary with a small mass ratio of 0.267 and the two components are in poor thermal contact. AD Cnc has  相似文献   

9.
The formation of dust grains in steady state dust driven winds around oxygen-rich AGB stars has been investigated to clarify the carrier of the observed 13μm feature. In the calculations not only homogeneous Al2O3 and silicate grains but also heterogeneous grains consisting of an Al2O3 core and a silicate mantle are included simultaneously. The radiation transfer calculations based on the results of condensation calculations demonstrate that the core-mantle grains consisting of an α-Al2O3 core and a silicate mantle formed in the vicinity of the sonic point can produce a distinctive emission feature similar to the observed 13μm feature when the mass loss rate is less than 2 × 10-5M·/yr. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

10.
Detailed ISOPHOT observations of the far infrared excess of α Lyrae (Vega) are presented. The data comprise photometry in the range 25μm to 200μm and high resolution 60μm scan data to compare with 60μm and 90μm oversampled maps. The dust disk around Vega is clearly resolved. In addition similar maps of HD98800, SAO226057, SAO186777 and α Piscis Austrinus (HR8728) are evaluated, resolving the disks of two Vega-like stars/candidates and providing upper limits for the size of the other two. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

11.
The existence and stability of triangular libration points in the relativistic restricted three-body problem has been studied. It is found that L4,5 are unstable in the whole range 0 ≤ μ ≤ 1/2 in contrast to the classical restricted three-body problem where they are stable for 0 < μ < μ0, where μ is the mass parameter and μ0 = 0.03852.... This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

12.
We present ISO observations of bright, high-mass southern starforming regions with the Short Wavelength Spectrometer (SWS) and Long Wavelength Spectrometer (LWS). The selected targets show a range of pre-main sequence evolutionary phases. Whereas some objects still show interstellar ice features, the most evolved objects are coincident with ultra-compact HII regions and show strong emission lines from atomic species and polycyclic aromatic hydrocarbons (PAHs). We discuss the ISO spectra between 2.5 - 200 μm of selected southern star-forming regions in the context of their evolution. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

13.
TZ Lyrae： an Algol-type Eclipsing Binary with Mass Transfer   总被引：1，自引：0，他引：1  
We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt = 7.18 × 10?8d yr?1, indicating that a mass transfer from the less massive component to the more massive one at a rate of dm = 2.21 × 10-8M⊙yr-1. The cyclic component, with a period of P3 = 45.5 yr and an amplitude of A = 0d.0040, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type eclipsing binary with a mass ratio of q = 0.297(±0.003). The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.  相似文献   

14.
ISO-SWS observations of the highly obscured young stellar object W 33A reveal two broad absorption features centered at 7.24 and 7.40 μm. The position and width of these features indicates that they are due to the XH bending mode (X = C, N, or O) of molecules in the solid state. Comparison to interstellar ice analogs shows that the 7.24 μm band can be well matched by solid formic acid (HCOOH), while the 7.40 μm band can be fitted both by the formate ion (HCOO-) and acetaldehyde (CH3HCO). The laboratory spectra reveal additional strong features of these molecules which should make a more definite identification straightforward. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

15.
ISOPHOT has been used to obtain low resolution spectra from 2.5μm to 5μm and 5.8μm to 11.6μm and multi-aperture photometry at 60μm of several evolved stars; oxygen-rich and carbon-rich (including the peculiar carbon-rich stars R CrB and RY Sgr). R CrB was observed early in the ISO mission, 3 weeks after it had been at minimum light. Another spectrum was obtained several months later. The second spectrum shows that the broad plateau (from around 6μm to 8μm) is still present but the flux density has declined from 60Jy to 50Jy. The spectrum for RY Sgr shows the same type of plateau. The multi-aperture data suggest that the dust shells are resolved around R CrB, RY Sgr, Y CVn and RS Lib. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

16.
The near-contact binary UU Lyn with an F3V-type primary was observed in 2005 and 2006. With the latest version of the Wilson-Devinney code, the photometric elements were computed. The results reveal that UU Lyn is a marginal contact system with a large temperature difference of about 1900K between the primary and secondary components. All available eclipse times, including new ones, were used in the analysis. The results show that the orbital period of this system undergoes a continuous decrease at a rate of dP/dt =-1.84× 10-8dyr-1. With the period decrease, UU Lyn may evolve from the present short- period marginal contact system into a contact system with true thermal contact. This target might just be undergoing the cycles predicted by the theory of thermal relaxation oscillations (TRO). It is an interesting example resembling BL And, GW Tau, ZZ Aur, KQ Gem, CN And and AD Cnc, that lie in the key evolutionary stage.  相似文献   

17.
New multi-color photometry of the solar-type contact binary OO Aql was obtained in 2012 and2013, using the 60 cm telescope at Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences. From two sets of light curves LC_1 and LC_2, photometric models were performed by using the 2003 version of the Wilson-Devinney code. The overcontact factor of the binary system was determined to be f = 37.0(±0.5)%. The intrinsic variability of this binary occurs in light maxima and minima, which could result from a possible third component and magnetic activity of the late type components. Based on all available light minimum times, the orbital period may change in a complicated mode,i.e., sudden period jumps or continuous period variations. The period of OO Aql may possibly undergo a secular period decrease with a rate of d P /dt =-3.63(±0.30) × 10~(-8)d yr~(-1), superimposed by two possible cyclic variations in the O- C curve. The long-term period decrease may be interpreted as conserved mass transfer from the more massive component to the less massive one. The 21.5-yr oscillation may be attributed to cyclic magnetic activity, and the 69.3-yr one may result from the light-time effect of an unseen tertiary body.  相似文献   

18.
We present UKIRT spectroscopy of Nova Cassiopeia 1993 (= V705 Cas) in KLNQ bands, taken in 1994 and 1995. Fitting the continuum indicates a dust temperature T ∼ 740 – 750 K in the latter part of 1994; this is similar to earlier measurements, and consistent with the “isothermal” behaviour observed in novae with optically thick dust shells. The β-index drops from 0.8 to 0.4 over the same period. This suggests grain growth; grain diameter increases from < 0.54 μm around day 256, to > 0.57 μm by day 342. The UIR features differ from those in other Galactic sources, and are similar to those in V842 Cen. This suggests fundamental differences between the UIR carriers, or environments, in novae and other Galactic sources. The silicate feature is consistent with an amorphous structure, in contrast to previous novae. We believe that grains in V705 Cas form two populations: silicates, and hydrocarbons. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

19.
We present CCD B and V light curves,obtained in the year 2006,and a photometric solution of the low-mass ratio contact binary ASAS 021209+2708.3. With our data we were able to determine six new times of minimum light and refine the orbital period of the system to 0.3181963 days.The light curves are analyzed using the 2003 version of the Wilson-Devinney program and the analysis was performed with and without adding a spot on the surface of one star because the light curves appear to exhibit a typical O’Conne...  相似文献   

20.
We present a star catalog extracted from the Lunar-based Ultraviolet Telescope(LUT) survey program. LUT's observable sky area is a circular belt around the Moon's north pole, and the survey program covers a preferred area of about 2400 deg~2 which includes a region of the Galactic plane. The data are processed with an automatic pipeline which copes with stray light contamination, artificial sources, cosmic rays, flat field calibration, photometry and so on. In the first release version, the catalog provides high confidence sources which have been cross-identified with the Tycho-2 catalog. All the sources have signalto-noise ratio larger than 5, and the corresponding magnitude limit is typically 14.4 mag, but can be as deep as ～16 mag if stray light contamination is at the lowest level. A total of 86 467 stars are recorded in the catalog. The full catalog in electronic form is available online.  相似文献   

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