i=0°和 i=90°自转星的绝对星等差     

朱慈墭 《天文学报》1963,(1)

一、引言1924年,蔡伯(H.Von Zeipel)提出了一条著名的定理:一个处于流体静力学平衡和辐射平衡的自转星,通过水准面上一面元的总辐射流和该面元处的有效重力成正比.因而,自转星表面的亮度随着纬度的不同而不同,两极区域此赤道区域亮一些,这被称为“重力昏暗”效应.后来,在计算快速自转恒星受自转畸变了的谱线的理论轮廓以及研究密近交食双星的光变时,基于蔡伯定理的重力昏暗得到了应用.  相似文献   

Middle atmosphere lunar tides at Saskatoon (52°N, 107°W)     

《Planetary and Space Science》1987,35(4):445-449

Winds have been measured continuously at the Medium Frequency (MF) Radar Observatory at Saskatoon since 1978. A simple analysis has been used to obtain the characteristics of the lunar semidiurnal tide (12.42 h) for summer and winter months. Amplitudes increase with height to 3, 4 ms⁻¹ in summer, winter respectively near 100 km, and the mainly circular tide has vertical wavelengths of ~ 75 km. Comparisons with other observatories and theoretical models are made.  相似文献   

The Mars opposition effect at 20°N. latitude and 20°W. longitude     

Thomas E. Thorpe 《Icarus》1979,37(2):389-398

Low phase angle observations in the Chryse-Acidalia region have been obtained the Viking Orbiter 1 spacecraft under clearer atmospheric conditions than reported earlier. A variety of surface features were recorded, e.g., crater streaks, dark and bright patches. Several findings for this scene include: an abrupt brightness increase (10%) was found at phase angles less than 3°, an effect dependent on surface albedo and possibly particle distribution; a slight weakening of reflectance surge with decreasing wavelengths; a larger opposition effect for features of high albedo was recorded; and a greater reddening with increase phase angle took place for low albedo regions. Both reflectance and contrast values are provided at three wavelengths as a function of phase angle from 0.15 to 20°.  相似文献   

Photometry of BD −7° 3007     

B. S. Shylaja 《Astrophysics and Space Science》1987,130(1-2):181-185

Photometric observations of BD –7° 3007 in B and V filters are reported. Rapid flickering appears to be present at all phases, implying an unfavourable angle of inclination of orbit for seeing eclipse effects. A modulation of the light curve of period about an hour is present only on one night. The continuum energy distribution agrees with that of Com (GO V) in the longer wavelength region only.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.  相似文献   

The light variability of BD+25°2511     

A. V. Raveendran 《Astrophysics and Space Science》1984,99(1-2):171-173

Photometry of the spectroscopic binary BD+25°2511 obtained during the 1981, 1982, and 1983 observing seasons shows that it is a variable with a period of about 3.5 days.Paper presented at the Lembang-Bamberg IAU Colloquium No. 80 on Double Stars: Physical Properties and Generic Relations, held at Bandung, Indonesia, 3–7 June, 1983.  相似文献   

On the galactic plane discontinuity nearl=140°     

R. J. Dodd 《Astrophysics and Space Science》1976,44(1):85-99

Star counts, from measurements made by the GALAXY measuring machine, in unit B magnitude intervals were made in nine regions, each of 1.75 square degrees distributed about (l, b)= (140°, 0°). The mean density function and the mean variation of interstellar absorption with distance for the various areas were determined using a combination of theoretical and observed cumulative Wolf diagrams. For the same regions multi-colour (UBV) photographic photometry was used to identify early type stars. The distribution of these stars shows three main peaks which correspond well in distance with the Perseus, - and -spiral arms found by Verschuur from radio measurements of neutral hydrogen. The pattern made by the stellar arms in the (l, r) plane shows a discontinuity nearl=140°. From a consideration of both the star counts and the distribution of the reddened early type stars it is suggested that the cause of the discontinuity is a cloud with 0 _. ^m 7 total obscuration situated much nearer to the Sun than the Perseus arm and terminating on one side atl=140°.  相似文献   

First Byurakan Spectral Sky Survey. Blue stellar objects. VII. Zone +61° ≤δ ≤, +65°     

H. V. Abrahamian  A. M. Mickaelian 《Astrophysics》1994,37(1):27-35

The seventh list of blue stellar objects in the second part of the First Byurakan Spectral Sky Survey (FBS) is presented. The objects are located in the zone + 61° + 65° and 5 ^h 30^m 18 ^h 40 ^m .The list contains data on 119 blue stellar objects detected, of which 73 are previously unknown. A preliminary classification of the objects is given. The limiting magnitude of the FBS plates are determined using the photometric calibration of the charts of the Palomar Sky Survey.Translated fromAstrofizika, Vol. 37, No. 1, pp. 43–55, January–March, 1994.  相似文献   

Seasonal variations of diffuse solar radiation at Ilorin (8°32′N,4°46′E), Nigeria     

Moses G. Iziomon  Theophilus O. Aro 《Astrophysics and Space Science》1995,228(1-2):1-18

Hourly diffuse solar irradiance (H_d) and the corresponding global irradiance (H) falling on a horizontal surface at Ilorin (8°32N,4°46E), Nigeria has been measured for a period of fifteen months commencing from February, 1993. As expected, each monthly mean diurnal variation of H_d exhibits a mid-day maximum, while that of the ratio H_d/H exhibits a minimum. The month to month variations of these parameters are consequent on the dominant atmospheric conditions observed in the months concerned. The monthly average daily total of diffuse radiation (H_dm) was found to be highest in February, 1994 with a value of (3347 ± 45) Wm^–2day^–1, mainly due to the effects of Harmattan haze and thin clouds, while it was found to be lowest in November, 1993 and January, 1994 with a value of about 2500 Wm^–2day^–1. Similarly, the ratio of the monthly average daily total of diffuse radiation to the monthly average daily total of global radiation (H_dm/H_m) had the lowest value of 0.49 in the relatively clear sky month of November, 1993 and the highest value of 0.74 in the mainly cloudy month of August, 1993. On an annual average, the diffuse component constituted about 60% of the global solar radiation arriving on the ground at Ilorin, Nigeria primarily due to clouds and Harmattan haze which are seasonal, in addition to the constant background of molecular scattering.  相似文献   

First Byurakan Spectral Sky Survey. Stars of late spectral types. −11° ≤ δ ≤ −7° belt     

K. S. Gigoyan  V. V. Hambaryan  M. Azzopardi 《Astrophysics》1998,41(4):356-366

A 10th list of late-type M and C stars found on plates of the First Byurakan Spectral Sky Survey in the − 11° ≤ δ ≤ − 7° belt with an area of about 1070 deg² is given. The list contains data on 169 red stars, 117 of which were found for the first time: 8 are new C stars, 3 are Cstar candidates, 104 are M stars, 1 is either an M or an S star, and 1 object on the survey plate cannot be classified. Of the 117 objects, 47 are unidentified IRAS sources. A statistical analysis of the objects that are and are not identified with IRAS sources shows that the identified stars are, with a high probability, brighter and have relatively more massive envelopes. Two stars were found to have fairly large brightness variability (with an amplitude of at least 6^m.O). Gasdust shells are assumed to exist around nine of the IRAS sources. The equatorial coordinates, spectral types, and stellar magnitudes, determined on Palomar E maps, are given for the selected objects. Translated from Astrofizika, Vol. 41. No. 4, pp. 545–559, October–December, 1998.  相似文献   

First Byurakan Spectral Sky Survey. Blue stellar objects. VIII. zone +65° ≤ δ ≤, + 69°     

H. V. Abrahamian  A. M. Mickaelian 《Astrophysics》1994,37(2):117-123

The eighth list of blue stellar objects in the second part of the First Byurakan Spectral Sky Survey (FBS) is presented. The objects are located in the zone +65° +69° and 5 ^h 15^m 18 ^h 05^m.The list contains data on 98 blue stellar objects detected, of which 73 are previously unknown. A preliminary classification of the objects is given. The exact coordinates of the centers and the limiting magnitudes of the plates for this zone have been determined using the charts of the Palomar Sky Survey.Translated from Astrofizika, Vol. 37, No. 2, pp. 197–206, April–June, 1994.This work has been performed with financial support of the ESO C&EE fund (A-02-043).  相似文献   

Mercury: The Image of the Planet in the 210°–285° W Longitude Range Obtained by the Short-Exposure Method     

Ksanfomality  L. V. 《Solar System Research》2003,37(6):469-479

For the purpose of obtaining images of the unknown portion of Mercury, we continued the previously started series of observations of this planet by the short exposure method. Several thousand electronic images of Mercury have been acquired on 1–2 May 2002 under good meteorological conditions at the high-altitude Skinakas Astrophysical Observatory of Iraklion University (Crete, Greece, 35°13 E, 24°54 N) during the evening elongation. The phase angle of Mercury was 95°–99° and the observed range of longitudes was 210°–285° W. Observations were carried out using Ritchy–Chrétien telescope (D = 1.29 m, F = 9.857 m) with the KS 19 filter cutting wavelengths shorter than about 700 nm. The planet's disk was seen, on average, at an angle of 7.75 arcsec. The image scale was equal to 47.8 m/arcsec. We used a CCD with a pixel size of 7.4 × 7.4 m in the regime of short exposures. By processing a great number of electronic images, we succeeded in obtaining a sufficiently distinct synthesized image of the unknown portion of Mercury's surface. The most prominent formation in this region is a giant basin (or cratered mare) centered at about 8° N, 280° W, which was given a working name Skinakas basin (after the name of the observatory where observations were made). By its size, the interior part of this basin exceeds the largest lunar Mare Imbrium. As opposed to Mare Imbrium, the Skinakas basin is presumably of impact origin. Its relief resembles that of Caloris Planitia but the size is much larger. A series of smaller formations are also seen on synthesized images. The resolution obtained on the surface of Mercury is about 100 km, which is close to the telescope diffraction limit. Also considered are the published theoretical estimations of the possible advantages offered by the short exposure method. Some results obtained by other research groups are discussed.  相似文献   

First Byurakan Spectral Sky Survey. Stars of Late-Spectral Types. XIV. Zone +13° ≤ δ ≤ +33°     

K. S. Gigoyan  H. V. Abrahamyan  M. Azzopardi  N. Mauron  D. Russeil  P. Sinamyan 《Astrophysics》2003,46(4):475-488

We present the fourteenth list of faint late M and carbon type stars detected on the plates of the First Byurakan Spectral Sky Survey in the zone +13° +33° covering about 4736 sq. degrees. From 260 stars, 118 are newly detected objects: they are 19 carbon stars, 5 carbon star candidates, and 94 M-type stars. Among 118 detected objects 73( 57 PSC + 16 FSC ) are unclassified IRAS sources. Accurate positions, spectral classes, red magnitudes, color indices, and near-infrared J, H and K photometry are given, using several astronomical databases. Finding charts from DSS are given for the most interesting objects.  相似文献   

First Byurakan Spectral Sky Survey. Blue Stellar Objects. XII. The Region -3° ≤ δ ≤ +1°     

G. V. Abrahamyan  P. K. Sinamyan  K. S. Gigoyan 《Astrophysics》2003,46(1):46-57

The twelfth list of blue stellar objects in the second part of the First Byurakan Spectral Sky Survey (FBS) is presented. This list contains 143 objects in the region -3° +1° at high latitudes with an area of approximately 992 square degrees (62 fields). The objects have magnitudes V of 11.8-18.1 and B-V colors ranging from -0.82 to +0.81. Of the 143 objects, 51 have been discovered for the first time. Equatorial coordinates, V magnitudes, color indices, and preliminary classifications of the objects are given. DSS identification charts are given for the newly discovered objects.  相似文献   

First Byurakan Spectral Sky Survey. Stars of Late-Spectral Types. XIII. Zone +1° ≤ δ ≤ +13°     

K. S. Gigoyan  H. V. Abrahamyan  M. Azzopardi  D. Russeil 《Astrophysics》2002,45(3):322-333

The thirteenth list of faint late M and carbon type stars detected on the plates of the First Byurakan Spectral Sky Survey in zone +1° +13° covering about 3118 sq. degrees is presented. From 285 stars, 161 are newly detected objects: they are 17 carbon stars, 25 carbon star candidates, and 117 M-type stars. The spectral type of two objects is assumed to be between M8 - M9 or late N-subtypes. Among 161 objects, 85 (66 PSC + 19 FSC) are unclassified IRAS sources. Accurate positions, spectral classes, red magnitudes, and color indices are given using several astronomical databases. Finding charts from DSS are given for the most interesting objects.  相似文献   

Photometric variability of the protoplanetary nebula LSIV-12°111     

V. P. Arkhipova  N. P. Ikonnikova  R. I. Noskova  G. V. Komissarova 《Astronomy Letters》2002,28(4):257-260

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 ～1^d. 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   

First Byurakan Spectral Sky Survey. Stars of Late Spectral Types. XI. Zone -7° ≤ δ ≤ -3°     

K. S. Gigoyan  H. V. Abrahamyan  M. Azzopardi  D. Russeil 《Astrophysics》2001,44(1):88-97

The eleventh list of faint late M and carbon type stars detected on the plates of the First Byurakan Spectral Survey in zone -7° -3° and covering about 1000 square degrees is presented. From 126 detected stars, 88 are newly discovered objects: they are 6 carbon stars, 8 carbon star candidates, and 74 M-type stars; among the latter 38 (26 PSC + 12 FSC) are unclassified IRAS sources, and one object is an unclassified ROSAT source. Distances to the 6 newly discovered early-type carbon stars are estimated. Equatorial coordinates, red magnitudes, and spectral classes determined from the Palomar E-charts are provided. The lack of optical counterparts on Palomar O and E maps for two detected late M-type stars indicates a large variability in brightnesses of these objects (amplitude not smaller than 7.0 magnitude).  相似文献   

First Byurakan Spectral Sky Survey. Stars of Late Spectral Types. XII. Zone -3° ≤ δ ≤ +1°     

K. S. Gigoyan  H. V. Abrahamyan  M. Azzopardi  D. Russeil 《Astrophysics》2001,44(3):328-334

The twelfth list of faint late M and carbon type stars detected on the plates of the First Byurakan Spectral Survey in zone -3° +1° covering about 1070 sq. degrees is presented. From 86 detected stars, 57 are newly discovered objects: they are 3 R-type carbon stars, 2 carbon star candidates and 52 M-type stars. Among the latter 34 (28 PSC + 6 FSC) are unclassified IRAS sources. Equatorial coordinates, spectral classes, color indices, and red magnitudes determined from the Palomar E-charts are presented.  相似文献   

2013年1月行星出没图（北纬40°）     

曹军 《天文爱好者》2012,(12):10-11

左图显示每日日落到次日日出之间的五颗行星出没状态及观测条件,包括晨昏蒙影时刻,水星与金星的出没时刻,火星、木星与土星的出没及中天时刻,以及月亮出没状态。横坐标为地方平时,纵坐标为日期。  相似文献   

2012年11月行星出没图（北纬40°）     

曹军 《天文爱好者》2012,(10):10-12

上图显示每日日落到次日日出之间的五颗行星出没状态及观测条件,包括晨昏蒙影时刻,水星与金星的出没时刻,火星、木星与土星的出没及中天时刻,以及月亮出没状态。横坐标为地方平时,纵坐标为日期。  相似文献   

2015年1月行星出没图（北纬40°）     

曹军 《天文爱好者》2014,(12):12-12

左图显示每日日落到次日日出之间的五颗行星出没状态及观测备件,包括晨昏蒙影时刻,水星与金星的出没时刻,火星、木星与土星的出没及中天时刻,以及月亮出没状态,横坐标为地方平时,纵坐标为日期。  相似文献