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1.
We study the radio galaxy RC J0105+0501 by using observations with RATAN-600, VLA, and 6-m Special Astrophysical Observatory telescope. The radio source has a structure resembling the FRII type and the spectral index α=1.23; it is identified with a faint galaxy of $22\mathop .\limits^m 8$ in R c . The optical object is $1\mathop .\limits^m 5$ brighter in V than it is in B and has an extended structure, which we interpret as intense Lyα line emission with redshift z≈3.5 and a continuum depression in the adjacent short-wavelength region. Based on BVR c I c photometry, we also estimated the age of the stellar population of the radio galaxy.  相似文献   

2.
We present our photometric observations of an early B supergiant with an infrared excess, the protoplanetary object LSIV-12°111, and the previously suspected variable star NSV 24971. We confirm its photometric variability. During two observing seasons (2000–2001), the star exhibited rapid irregular light variations with amplitudes $\Delta V \sim 0\mathop .\limits^m 3$ , $\Delta B \sim 0\mathop .\limits^m 3$ , and $\Delta U \sim 0\mathop .\limits^m 4$ and a time scale of ～1d. There is no correlation between the colors and magnitudes of the star. The variability patterns of LSIV-12°111 and two other hot post-AGB stars, V886 Her and V1853 Cyg, are shown to be similar.  相似文献   

3.
New photoelectric UBVRI observations of the eclipsing variable V 1016 Ori have been obtained with the AZT-11 telescope at Crimean Astrophysical Observatory and with the Zeiss-600 telescope at Mount Maidanak Observatory. Light curves are constructed from the new observations and from published and archival data. We use a total of 340, 348, 386, 185, and 62 magnitude estimates in the bands from U to I, respectively. An analysis of these data has yielded the following results. The photometric elements were refined; their new values are $Min I = JDH 2441966.820 + 65\mathop .\limits^d 4331E$ . The UBVRI magnitudes outside eclipse were found to be $5\mathop .\limits^m 95$ , $6\mathop .\limits^m 77$ , $6\mathop .\limits^m 75$ , $6\mathop .\limits^m 68$ , and $6\mathop .\limits^m 16$ , respectively. No phase effect was detected. We obtained two light-curve solutions: (1) assuming that the giant star was in front of the small one during eclipse, we determined the stellar radii, r s=0.0141 and r g=0.0228 (in fractions of the semimajor axis of the orbit); and (2) assuming that the small star was in front of the giant one, we derived r g=0.0186 and r s=0.0180 for the V band. The brightness of the primary star in the bands from U to I is L 1=0.96, 0.92, 0.90, 0.89, and 0.88, the orbital inclination is $i = 87^\circ .1$ , and the maximum eclipse phase is α0= 0.66. In both cases, we accepted the U hypothesis, assumed the orbit to be elliptical, and took into account the flux from the star Θ1 Ori E that fell within the photometer aperture. The first solution leads to a discrepancy between the primary radius determined by solving the light curve and the radial-velocity curve and its value estimated from the luminosity and temperature. This discrepancy is eliminated in the second solution, and it turns out that, by all parameters, the primary corresponds to a normal zero-age main-sequence star.  相似文献   

4.
We present photoelectric and photographic observations of the supergiant HD 179821 with a large infrared excess, a candidate for protoplanetary objects. Over, ten years of our UBV observations, the star exhibited semiregular light variations with amplitudes $\Delta V = 0\mathop .\limits^m 10$ , $\Delta B = 0\mathop .\limits^m 15$ , and $\Delta U = 0\mathop .\limits^m 25$ , as well as systematic color and light variations. From 1990 until 1996, the yearly mean U-B and B-V color indices decreased by 0.25 and 0.15, respectively. After 1996, the motion of the star in the two-color (B-V)-(U-B) diagram upward and to the left slowed down. The color excess that we derived from our observations, by assuming that the star’s spectral type was F3 I in the 1990s, is E(B-V)=1.0. The photographic observations of HD 179821 from 1899 until 1989 show that its brightness m pg generally increased while significantly fluctuating. An analysis of the observational data suggests that HD 179821 is most likely a post-AGB star of intermediate or low mass.  相似文献   

5.
Published photoelectric measurements over a wide wavelength range (0.36–18 µm) are used to study the continuum spectrum of the star Θ1 Ori C. The model that assumes the following three radiation sources is consistent with observations: (1) a zero-age main-sequence O7 star (object 1) of mass M 1=20M ⊙, radius R 1=7.4R ⊙, effective temperature T 2=37 000 K, and absolute bolometric magnitude $M\mathop {bol}\limits^1 = - 7\mathop .\limits^m 7$ ; (2) object 2 with M 2=15M ⊙, R 2=16.2R ⊙, T 2=4000 K, and $M\mathop {bol}\limits^2 = - 5\mathop .\limits^m 1$ ; and (3) object 3 with R 310 700 R ⊙, T 3=190 K, and $M\mathop {bol}\limits^3 = - 0\mathop .\limits^m 6$ . The visual absorption toward the system is $A_V = 0\mathop .\limits^m 95$ and obeys a normal law. The nature of objects 2 and 3 has not been elucidated. It can only be assumed that object 2 is a companion of the primary star, its spectral type is K7, and it is in the stage of gravitational contraction. Object 3 can be a cocoon star and a member of the system, but can also be a dust envelope surrounding the system as a whole.  相似文献   

6.
We obtained U BV R photometric and spectroscopic observations during the outburst of V838 Mon. Before its outburst, the B brightness of the star had been stable ( $\tilde15.^m 85$ ) for 45 years. This was a blue star with the color index $(B - V)_0 = - 0\mathop .\limits^m 03 \pm 0\mathop .\limits^m 1$ and may have been a cataclysmic variable. In the middle of March 2002, the outburst amplitude reached $8\mathop .\limits^m 1$ in B. The star has the counterpart V 1006/7 in M 31 in luminosity at maximum and in spectrum. The unusual spectrum at the premaximum stage originated in the expanding photosphere of a cool K-type giant. The expansion velocity of the photosphere was 150 km s?1; the maximum velocity in the expanding stellar envelope reached 500 km s?1. The absorption components of neutral metal lines were enhanced by a factor of 3 or 4 compared to a normal K-type star. No overabundance of s-process elements was found. One day before the brightness peak, an intense Hα emission line with broad wings, FWZI=3100 km s?1, and numerous lines of ionized metals appeared in V838 Mon, which is characteristic of normal classical novae. We show light, color, and spectral variations of the object.  相似文献   

7.
Updated proper motions for 328 probable members of the Praesepe are used to determine the distance to this open cluster by Hertzsprung's geometric method. The cluster distance was found to be r=171±15 pc, which corresponds to the distance modulus $V_0 - M_V = 6\mathop .\limits^m 16 \pm 0.19$ . The distance scale for open clusters is discussed.  相似文献   

8.
We present photoelectric and spectroscopic observations of the protoplanetary object V 1853 Cyg, a B supergiant with an IR excess. Over two years of its observations, the star exhibited rapid irregular light variations with amplitudes $\Delta V = 0\mathop .\limits^m 3$ , $\Delta B = 0\mathop .\limits^m 3$ , $\Delta U = 0\mathop .\limits^m 4$ and no correlation between color and magnitude. Its mean magnitude has not changed since the first UBV observations in 1973 (Drilling 1975). Low-resolution spectroscopic observations show that the spectrum of V 1853 Cyg in 2000 corresponded to that of a B1–B2 star with T eff ～ 20000 K. High-resolution spectroscopic observations confirm the conclusion that the profiles of absorption and emission lines are variable. We identified the star’s spectral lines and measured the equivalent widths of more than 40 lines. The star’s radial velocity is 〈V r 〉= ?49 × 5 km s?1, as measured from absorption lines, and ranges from–50 to–85 km s–1 for different lines, as measured from shell emission lines. The velocity of the dust clouds on the line of sight determined from diffuse interstellar bands (DIBs) and from interstellar Na I lines is 〈V r 〉= ?16 × 5 km s?1. The P Cyg profiles of the He I λ5876 Å and λ6678 Å lines suggest an ongoing mass loss by the star. An analysis of the observational data confirms the conclusion that the star belongs to the class of intermediatemass protoplanetary objects.  相似文献   

9.
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10.
A UBVR monitoring of the X-ray source 1RXS J220111+281849 was performed during August 2–21, 1999. Seven moderately intense ultraviolet flares with 1–3m amplitudes were detected. The object exhibits both rapid and slow flares. An unusual superintense flare with an $11\mathop .\limits^m 0$ amplitude in U was detected on August 18, 1999. Light curves of the flares are presented, and their physical parameters are briefly analyzed.  相似文献   

11.
Observations at the Crimean Astrophysical Observatory are used to show that the ultrahigh-energy gamma-ray flux from the galaxy Mk 501 varies with a $23\mathop .\limits^d 2$ period. The period was determined by the HEGRA team from the 1997 observations.  相似文献   

12.
We present our JHKLM photometry for R Cas performed during 1988–2000. The pulsation period of R Cas is $P \approx 429\mathop .\limits^d 6$ , with the maximum IR brightness lagging behind the maximum visual brightness by ～0.2 P. The amplitude of light variations appreciably decreases with increasing wavelength at λ≤3 μm. At λ>3 μm, this decrease virtually ceases. There is a step on the ascending branch of IR JHK brightness. The K-L color index increases linearly with K magnitude: $K - L = 0.304K + 1\mathop .\limits^m 20$ . The color temperature dependence, T K-L =f(K), is also linear: T K?L = ?622K + 1100 K. In going from minimum to maximum, the K flux (as well as the bolometric flux) from the star and its color temperature T K-L increase by a factor of ～2.2 and ～1.3, respectively.  相似文献   

13.
In 1982 and 1993, we carried out highly accurate photoelectric WBVR measurements for the close binary IT Cas. Based on these measurements and on the observations of other authors, we determined the apsidal motion $\left[ {\dot \omega _{obs} = {{(11\mathop .\limits^ \circ 0 \pm 2\mathop .\limits^ \circ 5)} \mathord{\left/ {\vphantom {{(11\mathop .\limits^ \circ 0 \pm 2\mathop .\limits^ \circ 5)} {100 years}}} \right. \kern-0em} {100 years}}} \right]$ . This value is in agreement with the theoretically calculated apsidal motion for these stars $\left[ {\dot \omega _{th} = {{(14^\circ \pm 3^\circ )} \mathord{\left/ {\vphantom {{(14^\circ \pm 3^\circ )} {100 years}}} \right. \kern-0em} {100 years}}} \right]$ .  相似文献   

14.
We presents the results of our study of new spectroscopic components in the visual binaries ADS 10683 (HD 160 239=BD?154 635=HIP 86412; G6/G8V; \(V = 9\mathop .\limits^m 08\); \(B - V = 0\mathop .\limits^m 76\); 2000: 17h39m24s, ?15°46′) and ADS 11791 (HD 175039=BD?054 798=HIP 92726; G5; \(V = 8\mathop .\limits^m 78\); \(B - V = 0\mathop .\limits^m 72\); 2000: 18h53m42s, ?05°33′). ADS 10683B and ADS 11791A are single-lined spectroscopic binaries; their orbital periods are \(6\mathop .\limits^d 9171 \pm 0\mathop .\limits^d 0002\) and \(50\mathop .\limits^d 514 \pm 0\mathop .\limits^d 004\), respectively. We constructed their radial velocity curves and computed their spectroscopic orbital elements.  相似文献   

15.
We examine the possibility that the observed cosmic-ray protons are of primary extragalactic origin. The present \(\bar p\) data are consistent with a primary extragalactic component having \(\bar p\) /p?3.2±0.7 x 10-4 independent of energy. Following the suggestion that most extragalactic cosmic rays are from active galaxies, we propose that most of the observed \(\bar p\) 's are alos from the same sites. This would imply the possibility of destroying the corresponding \(\bar \alpha \) 'sat the source, thus leading to a flux ratio \(\bar \alpha \) /α< \(\bar p\) /p. We further predict an estimate for \(\bar \alpha \) α～10-5, within the range of future cosmic-ray detectors. the cosmological implications of this proposal are discussed.  相似文献   

16.
Multi-colourWBVR photoelectric observations of the eclipsing binary AS Cam have been carried out and the photometric elements, absolute dimensions, and the angular velocity of a periastron motion ( \(\mathop \omega \limits^ \cdot _{obs}\) ) are determined. The obtained value of \(\mathop \omega \limits^ \cdot _{obs}\) is almost three times smaller than that theoretically predicted.  相似文献   

17.
We present new photometric UBVRI and spectroscopic observations of the symbiotic star YY Her during its return to quiescence after a strong outburst in 1993. High-resolution spectra of YY Her at similar phases at outburst maximum ?=0.48) and in quiescence ?=0.37) are presented for the first time. The ephemeris of YY Her has been refined P=586d). The last two observed minima (in 1999 and 2000) differed radically in shape from the 1997 minimum described previously. Both were sharp and deep $(\Delta U \sim 1\mathop .\limits^m 6, \Delta V \sim 0\mathop .\limits^m 9)$ . To explain this shape of the V light curve, which is only slightly affected by nebular emission, it should be assumed that the cool component of YY Her fills much of its Roche lobe and has a hot spot on the hemisphere facing the hot component. The emission spectrum rich in Fe II lines, which is characteristic of symbiotic stars, was observed during the outburst, but high-ionization lines (He II λ4686) were also observed. The He I λλ5876, 7065 lines exhibit distinct P Cyg profiles; the centers of the absorption components are shifted from the emission ones by V r≈100 km s?1, suggesting moderate outflow velocities.  相似文献   

18.
We present our photoelectric U BV observations of the candidate protoplanetary object IRAS 22223+4327 during four visibility seasons. The star exhibited periodic brightness variations with the maximum amplitudes \(\Delta U = 0\mathop .\limits^m 23, \Delta B = 0\mathop .\limits^m 18, and \Delta V = 0\mathop .\limits^m 12\) and a time scale of about 90 days, which is equal to the period derived by other authors from radial velocities. During these brightness variations, a correlation is observed between the (B-V) color index and brightness, which is characteristic of pulsations. We estimated the star’s spectral type from our photometric data to be F8 I. We detected a “deficit” of light in the U band. The star’s mean brightness and its spectral type appear to have not changed in the past half a century.  相似文献   

19.
Using γ-ray data detected by Fermi Large Area Telescope (LAT) and multi-wave band data for 35 TeV blazars sample, we have studied the possible correlations between different broad band spectral indices ( $\alpha_{\rm r.ir}$ , $\alpha_{\rm{r.o}}$ , $\alpha_{\rm r.x}$ , $\alpha_{\rm r.\gamma}$ , $\alpha_{\rm{ir.o}}$ , $\alpha_{\rm ir.x}$ , $\alpha_{\rm ir.\gamma}$ , $\alpha_{\rm o.x}$ , $\alpha_{\rm o.\gamma}$ , $\alpha_{\rm r.x}$ , $\alpha_{\rm x.\gamma}$ ) in all states (average/high/low). Our results are as follows: (1) For our TeV blazars sample, the strong positive correlations were found between $\alpha_{\rm r.ir}$ and $\alpha_{\rm{r.o}}$ , between $\alpha_{\rm r.ir}$ and $\alpha_{\rm r.x}$ , between $\alpha_{\rm r.ir}$ and $\alpha_{\rm r.\gamma}$ in all states (average/high/low); (2) For our TeV blazars sample, the strong anti-correlations were found between $\alpha_{\rm r.ir}$ and $\alpha_{\rm x.\gamma}$ , between $\alpha_{\rm{r.o}}$ and $\alpha_{\rm ir.\gamma}$ , between $\alpha_{\rm{r.o}}$ and $\alpha_{\rm o.\gamma}$ , between $\alpha_{\rm{r.o}}$ and $\alpha_{\rm x.\gamma}$ , between $\alpha_{\mathrm{ir.o}}$ and $\alpha_{\rm o.\gamma}$ , between $\alpha_{\rm r.x}$ and $\alpha_{\rm x.\gamma}$ , between $\alpha_{\rm ir.x}$ and $\alpha_{\rm x.\gamma}$ in all states (average/high/low). The results suggest that the synchrotron self-Compton radiation (SSC) is the main mechanism of high energy γ-ray emission and the inverse Compton scattering of circum-nuclear dust is likely to be a important complementary mechanism for TeV blazars. Our results also show that the possible correlations vary from state to state in the same pair of indices, Which suggest that there may exist differences in the emitting process and in the location of the emitting region for different states.  相似文献   

20.
We computed the occultations of stars brighter than 15m by the largest trans-Neptunian objects (TNOs) for the next ten years. In our search, we used the following catalogs: Hipparcos; Tycho2 with the coordinates of 2838666 stars taken from UCAC2 (Herald 2003); and UCAC2 (Zacharias et al. 2003) with 16356096 stars between \(12\mathop .\limits^m 00\) and \(14\mathop .\limits^m 99\) north of ?45° declination. We predicted the occultations of stars by the seventeen largest numbered TNOs, the recently discovered 2004 DW, and four known binary Kuiper Belt objects. We selected 64 events at solar elongations of no less than 30°, including the extremely rare occultation of a \(6\mathop .\limits^m 5\) star by the double asteroid (66652) 1999 RZ253 on October 4, 2007. Observations of these events by all available means are extremely important, since they can provide unique information about the sizes of TNOs and improve our knowledge of their orbits dramatically.  相似文献   

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