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1.
High-resolution Fourier Transform Spectrometer sunspot umbral spectra of the National Solar Observatory/National Optical Astronomy Observatory at Kitt Peak were used to detect rotational lines from 19 electronic transition bands of the molecules LaO, ScO and VO, in the wavenumber range of 11 775 to 20 600 cm−1. The presence of lines from the following transitions is confirmed: A 2 Π r1/2 – X 2 Σ +(0, 0; 0, 1), A 2 Π r3/2 – X 2 Σ +(1, 0), B 2 Σ + – X 2 Σ +(0, 0; 0, 1; 1, 0) and C 2 Π r1/2 – A′2Δ r3/2(0, 0; 1, 1) of LaO; A 2 Π r3/2 – X 2 Σ +(0, 0), A 2 Π r1/2 – X 2 Σ +(0, 0) and B 2 Σ + – X 2 Σ +(0, 0) of ScO; and C 4 Σ − – X 4 Σ −(0, 1; 1, 0; 0, 2) and (2, 0) of VO. However, the presence of A 2 Π r3/2 – X 2 Σ +(0, 0) and C 2 Π r3/2 – A′2Δ r5/2(0, 0; 1, 1) of LaO and C 4 Σ − – X 4 Σ −(0, 0) of VO are found to be doubtful because the lines are very weak, and detections are difficult owing to heavy blending by strong rotational lines of other molecules. Equivalent widths are measured for well-resolved lines and, thereby, the effective rotational temperatures are estimated for the systems for which the presence is confirmed.  相似文献   

2.
The Franck-Condon factors and r-centroids, which are very closely related to vibrational transition probabilities, have been evaluated by the more reliable numerical integration procedure for the bands of B 2 Σ+ - X 2 Σ+, C 2Σ+ - X 2 Σ+ andC 2 Σ+ - A 2 Πr systems of the astrophysical molecule BeF, using a suitable potential. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

3.
A high resolution spectrum of a sunspot umbra is used for identification of rotational lines due to (0, 0) band of the A 2Π–X 2Σ+ system and (0, 0), (1, 1), and (2, 2) bands of the B 2Σ+–X 2Σ+ system of the molecule SrF. The published sunspot umbral spectrum obtained with Fourier Transform Spectrometer and solar telescope of National Solar Observatory/National Optical Astronomy Observatory at Kitt Peak was used for the study. The new identification of more than 200 SrF lines in the umbral spectrum confirms that this molecule accounts for the majority of lines in the spectral range 15050 to 15360 cm−1 and 17240 to 17300 cm−1. Equivalent widths have been measured for well-resolved lines of these bands and the effective rotational temperatures have been estimated for which the presence is confirmed.  相似文献   

4.
The true experimental potential energy curves for the electronic ground states of astrophysically important TaO, TaS, ZrS and SiO+molecules are constructed by using the Rydberg–Klein–Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting techniques using the five parameters Hulburt-Hirschfelder (H-H) function. The estimated dissociation energies are 8.19 ± 0.17, 6.9 ±0.14, 5.89 ± 0.12 and 5.75 ± 0.12 eVfor TaO, TaS, ZrS and SiO+ respectively. These values are in good agreement with the literature values. The r-centriods and Franck–Condon factors (FC Factors) for the bands of K 2 φ 5/2 - X 2 Δ 3/2 (K-X) system of TaO, A-X 2 Δ (A-X) and B-X 2 Δ (B-X)systems of TaS, B 1 Π - X1 Σ+ (B-X) system of ZrS and B 2Σ+ - X2 Σ+ (B-X) and A 2 Π - X2 Σ+ (A-X)systems of SiO+ molecules have been calculated. The Franck–Condon factors (FC factors) are evaluated by the approximate analytical methods of Jarmain and Fraser. The absence of the bands of these systems is explained. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

5.
Vibrational transition probabilities namely Franck-Condon factors and -centroids have been evaluated using an approximate analytical method for theA-X systems of OH and PN. KKRV potential energy curves forX 2 i ,X 1+,A 2+, andA 1 states of OH and PN have been constructed using the latest spectroscopic data. The value of -centroids for the band have been found to increase linearly with the corresponding wavelengths. We show results for six new bands and OH and eight new bands of PN in the spectra of astronomical objects.  相似文献   

6.
The Franck-Condon (FC) factors and r-centroids for the bands systemC 1 Σ + → X 1 Σ + of AlD and E 2 Π → X 2 Σ + of CaH have been evaluated by means of a reliable numerical integration procedure by using a suitable potential. The dissociation energy, D e, for the electronic ground states of AlD and CaH have been estimated by the curve fitting method to the RKRV experimental potential curve turning out to be 3.01 eV and 2.32 eV, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

7.
For molecular identification in astrophysical sources, an astrophysicist needs some spectroscopic parameters such as dissociation energy, vibrational or rotational temperature of the source, band or line wavelengths, transition probability parameters, etc. The Franck-Condon(FC) factors are proportional to the transition probabilities. In this study, the FC factors and r-centroids for the vibronic (vibration-electronic) transitions C 1 Σ + → X 1 Σ + of aluminium hydride (AlH), b 3 Σ ( −) → a 3 Π, C 1 Σ + → A 1 Π & C ′1 Δ → Δ 1 Π of boron hydride (BH) have been evaluated and the results are presented in tables which include band origin/head wavelengths. The physical & astrophysical significances of our evaluated FC factors & r-centroids have been discussed and the possible presence of AlH in sunspot umbral spectra is also predicted. PACS: 33 · 70 · Ca  相似文献   

8.
We estimate the values of the cosmological parameters using the data about peculiar velocities of 1493 flat edge-on spirals from the RFGC catalogue. The obtained values Ω m = 0.21− 0.09 + 0.22, σ8 = 1.07− 0.24 + 0.28 differ from the WMAP values by approximately 2–3σ, but well agree with modern constraints on these parameters. Due to a strong correlation between these quantities the shape of the 1σ, 2σ and 3σ-boundaries are rather narrow. This gives us the opportunity to use this estimation to verify the corresponding values, obtained by different methods.  相似文献   

9.
Experimental results on fast ion collision with icy surfaces having astrophysical interest are presented. 252Cf fission fragments projectiles were used to induce ejection of ionized material from H2O, CO2, CO, NH3, N2, O2 and Ar ices; the secondary ions were identified by time-of-flight mass spectrometry. It is observed that all the bombarded frozen gas targets emit cluster ions which have the structure XnR±, where X is the neutral ice molecule and R± is either an atomic or a molecular ion. The shape of the positive or negative ion mass spectra is characterized by a decreasing yield as the emitted ion mass increases and is generally described by the sum of two exponential functions. The positive ion water ice spectrum is dominated by the series (H2O)nH3O+ and the negative ion spectrum by the series (H2O)nOH− and (H2O)nO−. The positive ion CO2 ice spectrum is characterized by R+ = C+, O+, CO+, O2+ or CO2+ and the negative one by R− = CO3−. The dominant series for ammonia ice correspond to R+ = NH4+ and to R− = NH2−. The oxygen series are better described by (O3)nOm+ secondary ions where m = 1, 2 or 3. Two positive ion series exist for N2 ice: (N2)nN2+ and (N2)nN+. For argon positive secondary ions, only the (Ar)nAr+ series was observed. Most of the detected molecular ions were formed by one-step reactions. Ice temperature was varied from ∼20 K to complete sublimation.  相似文献   

10.
The zirconium oxide (ZrO) is well known for its astrophysical importance. The radiative transition parameters that include Franck-Condon (FC) factor, r-centroid, electronic transition moments, Einstein coefficient, band oscillator strengths, radiative life time and effective vibrational temperature have been estimated for e 1Π–X 1Σ+ and 1Σ+–X 1Σ+ band systems of 90ZrO molecule for the experimentally known vibrational levels using RKR potential energy curves. A reliable numerical integration method has been used to solve the radial Schr?dinger equation for the vibrational wave functions of upper and lower electronic states based on the latest available spectroscopic data and known wavelengths. The estimated radiative transition parameters are tabulated. The effective vibrational temperatures of these band systems of 90ZrO molecule are found to be below 4200 K. Hence, the radiative transition parameters help us to ascertain the presence of 90ZrO molecule in the interstellar medium, S stars and sunspots.  相似文献   

11.
Two spectra of the ultra-violet nightglow from 1900 Å to 3400 Å have been recorded by a fast wide-field spectrograph during balloon flights from Aire sur Adour, France on 15 September, 1969 and on 5 October, 1970. These two spectra are composed of theOi line at 2972 Å, of the molecular oxygen Herzberg band systemA 3 u + X 3 g – and of a molecular band system that seems to belong to the NO SystemX 2 C 2 X +, situated at 1991 ű4 Å, 2060 ű4 Å and 2136 ű4 Å. Around 2540 Å, there is absorption by ozone at the altitudes at which the spectra were recorded (35 km and 40 km). We present our calculated value of ozone absorption at 35 km, and the zenith-horizon variation of the nightglow emission.  相似文献   

12.
Bonev  T.  Jockers  K.  Credner  T. 《Earth, Moon, and Planets》1997,77(3):245-252
Fabry-Pérot interferograms of comet Hale-Bopp were obtained on several nights in March and April 1997. For this purpose we utilized the 2-channel focal reducer of the Max-Planck-Institute for Aeronomy at the 2-m telescope of the Pik Terskol Observatory. Solid Fabry-Pérot etalons of resolving power 30000 were used in both channels of the focal reducer. The main aim of this study is to measure the velocities and abundances of OH+ and H2O+, both ions closely related to the same parent molecule, H2O. In the blue channel interferograms we identified several individual OH+ rotational lines of the A3Πi - X3Σ− (0-0) transition and measured their Doppler shifts. The target emissions in the red channel were the H2O+ lines of the A2A1 − X2B1 (10-0) band. We found that the line of sight velocities, obtained from the Doppler shifted wavelengths of emissions in the comet are higher in sunward direction than in the plasma tail and do not exceed 20 km s–1. The corresponding values, deprojected in antisolar direction, are consistent with predictions by magnetohydrodynamical models of the solar-wind-comet interaction, when one accounts for the extremely high gas production rate of comet Hale-Bopp. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
We present multi-colour CCD observations of the low-temperature contact binaries, V453 Mon and V523 Cas. Their light curves are modelled to determine a new set of stellar and orbital parameters. Analysis of mid-eclipse times yields a new linear ephemeris for both systems. A period decrease (dP/dt=2.3×10−7 days/yr) in V453 Mon is discovered. V523 Cas, however, is detected to show a period increase (dP/dt=9.8×10−8 days/yr) because of the mass transfer of a rate of 1.1×10−7 M⊙ yr−1, from a less massive donor. Using these findings we can determine the physical parameters of the components of V523 Cas to be M 1=0.76 (3)M ⊙, M 2=0.39 (2)M ⊙, R 1=0.74 (2)R ⊙, R 2=0.55 (2)R ⊙, L 1=0.19 (3)L ⊙, L 2=0.14 (3)L ⊙, and the distance of system as 46(9) pc.  相似文献   

14.
Due to the recent all-sky, high-precision measurement of microwave background anisotropies by WMAP, a value for baryon-to-photon ratio η was obtained. At the WMAP value for η, the 4HE abundance was predicted. In this article we use a simple semi-analytical method with 4He predicted and measured values to place a limit on the variation of the gravitational constant G. We find using a conservative range for the measured values for Y p , that ΔG/G is constrained between −0.26 and 0.15. If we assume a monotonic power law time dependence G∼t −β then β values is constrained between −0.008 and 0.0038, which translate into . This compares well with results obtained by others using full numerical analysis.   相似文献   

15.
We consider the Newtonian planar three-body problem with positive masses m 1, m 2, m 3. We prove that it does not have an additional first integral meromorphic in the complex neighborhood of the parabolic Lagrangian orbit besides three exceptional cases ∑m i m j /(∑m k )2 = 1/3, 23/33, 2/32 where the linearized equations are shown to be partially integrable. This result completes the non-integrability analysis of the three-body problem started in papers [Tsygvintsev, A.: Journal für die reine und angewandte Mathematik N 537, 127–149 (2001a); Celest. Mech. Dyn. Astron. 86(3), 237–247 (2003)] and based on the Morales–Ramis–Ziglin approach.  相似文献   

16.
We analyze the three-dimensional kinematics of about 82 000 Tycho-2 stars belonging to the red giant clump (RGC). First, based on all of the currently available data, we have determined new, most probable components of the residual rotation vector of the optical realization of the ICRS/HIPPARCOS system relative to an inertial frame of reference, (ω x , ω y , ω z ) = (−0.11, 0.24, −0.52) ± (0.14, 0.10, 0.16) mas yr−1. The stellar proper motions in the form μα cos δ have then be corrected by applying the correction ω z = −0.52 mas yr−1. We show that, apart from their involvement in the general Galactic rotation described by the Oort constants A = 15.82 ± 0.21 km s−1 kpc−1 and B = −10.87 ± 0.15 km s−1 kpc−1, the RGC stars have kinematic peculiarities in the Galactic yz plane related to the kinematics of the warped stellar-gaseous Galactic disk. We show that the parameters of the linear Ogorodnikov-Milne model that describe the kinematics of RGC stars in the zx plane do not differ significantly from zero. The situation in the yz plane is different. For example, the component of the solid-body rotation vector of the local solar neighborhood around the Galactic x axis is M 32− = −2.6 ± 0.2 km s−1 kpc−1. Two parameters of the deformation tensor in this plane, namely M 23+ = 1.0 ± 0.2 km s−1 kpc−1 and M 33 − M 22 = −1.3 ± 0.4 km s−1 kpc−1, also differ significantly from zero. On the whole, the kinematics of the warped stellar-gaseous Galactic disk in the local solar neighborhood can be described as a rotation around the Galactic x axis (close to the line of nodes of this structure) with an angular velocity −3.1 ± 0.5 km s−1 kpc−1 ≤ ΩW ≤ −4.4 ± 0.5 km s−1 kpc−1.  相似文献   

17.
Based on data for 102 OB3 stars with known proper motions and radial velocities, we have tested the distances derived by Megier et al. from interstellar Ca II spectral lines. The internal reconciliation of the distance scales using the first derivative of the angular velocity of Galactic rotation Ω′0 and the external reconciliation with Humphreys’s distance scale for OB associations refined by Mel’nik and Dambis show that the initial distances should be reduced by ≈20%. Given this correction, the heliocentric distances of these stars lie within the range 0.6–2.6 kpc. A kinematic analysis of these stars at a fixed Galactocentric distance of the Sun, R 0 = 8 kpc, has allowed the following parameters to be determined: (1) the solar peculiar velocity components (u ⊙, v ⊙, ω ⊙) = (8.9, 10.3, 6.8) ± (0.6, 1.0, 0.4) km s−1; (2) the Galactic rotation parameters Ω0 = −31.5 ± 0.9 km s−1 kpc−1, Ω′0 = +4.49 ± 0.12 km s−1 kpc−2, Ω″0 = −1.05 ± 0.38 km s−1 kpc−3 (the corresponding Oort constants are A = 17.9 ± 0.5 km s−1 kpc−1, B = −13.6 ± 1.0 km s−1 kpc−1 and the circular rotation velocity of the solar neighborhood is |V 0| = 252 ± 14 km s−1); (3) the spiral density wave parameters, namely: the perturbation amplitudes for the radial and azimuthal velocity components, respectively, f R = −12.5±1.1 km s−1 and f ϑ = 2.0 ± 1.6 km s−1; the pitch angle for the two-armed spiral pattern i = −5.3° ± 0.3°, with the wavelength of the spiral density wave at the solar distance being λ = 2.3 ± 0.2 kpc; the Sun’s phase in the spiral wave x ⊙ = −91° ± 4°.  相似文献   

18.
A high-resolution spectrum clearly shows the presence of A 6Σ+–X 6Σ+(0,0;0,1;1,0;2,0;2,1) and (2,2) bands system of CrH molecular lines in the spectral range 10,000 cm−1 to 14,050 cm−1. At least 3928 lines of the six bands, accounting for 57% of the lines registered in the laboratory can be identified with certainty in the sunspot spectrum. Most of the lines are found blended with TiO, CaH, MgH and other atomic species. These molecular lines are typically much more temperature sensitive than atomic lines, which make them ideal, complementary tool for studying cool stellar atmospheres as well as the internal structure of sunspots. Equivalent width for an adequate number of well identified molecular lines of these bands using the Gaussian-profile approximation method versus rotational quantum number J has been used to determine the effective rotational temperature of the CrH molecule. The range of effective rotational temperature value obtained from these bands is 1766 K to 2442 K. This range agrees well with the effective rotational temperatures derived for other molecules in sunspot umbrae.  相似文献   

19.
We make a statistical analysis of the periodsP and period-derivativesP of pulsars using a model independent theory of pulsar flow in theP-P diagram. Using the available sample ofP andP values, we estimate the current of pulsars flowing unidirectionally along theP-axis, which is related to the pulsar birthrate. Because of radio luminosity selection effects, the observed pulsar sample is biased towards lowP and highP. We allow for this by weighting each pulsar by a suitable scale factor. We obtain the number of pulsars in our galaxy to be 6.05−2.80 +3.32 × 105 and the birthrate to be 0.048−0.011 +0.014 pulsars yr−1 galaxy−1. The quoted errors refer to 95 per cent confidence limits corresponding to fluctuations arising from sampling, but make no allowance for other systematic and random errors which could be substantial. The birthrate estimated here is consistent with the supernova rate. We further conclude that a large majority of pulsars make their first appearance at periods greater than 0.5 s. This ‘injection’, which runs counter to present thinking, is probably connected with the physics of pulsar radio emission. Using a variant of our theory, where we compute the current as a function of pulsar ‘age’ (1/2P/P), we find support for the dipole braking model of pulsar evolution upto 6 × 106 yr of age. We estimate the mean pulsar braking index to be 3.7−0.8 +0.8.  相似文献   

20.
Here the effect of rotation up to third order in the angular velocity of a star on the p, f and g modes is investigated. To do this, the third-order perturbation formalism presented by Soufi et al. (Astron. Astrophys. 334:911, 1998) and revised by Karami (Chin. J. Astron. Astrophys. 8:285, 2008), was used. I quantify by numerical calculations the effect of rotation on the oscillation frequencies of a uniformly rotating β-Cephei star with 12 M ⊙. For an equatorial velocity of 90 km s−1, it is found that the second- and third-order corrections for (l,m)=(5,−4), for instance, are of order of 0.07% of the frequency for radial order n=−3 and reaches up to 0.6% for n=−20.  相似文献   

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