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  • 1
    Electronic Resource
    Electronic Resource
    Possibility of 24MgH+ in the solar atmosphere-high resolution rotation-vibration spectra (1976)
    Springer
    Solar physics 49 (1976), S. 217-230 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High resolution rotation-vibration spectra of Δv = 1 and 2 sequences of 24MgH+ are obtained by a differencing process invoking the known structures of electronic bands observed in the region 214–340 nm. A reversal of R branch (band head formation) is noticed in each of the rotation-vibration bands. The J = 1 → J = 0 transition is predicted to be at 376098, 365301, 354286 and 342981 MHz for v = 0,1,2 and 3, respectively, in the ground electronic state 1∑+. The equilibrium rotational constants B e, α e and r e for the X 1•E+ state are found 6.4637cm−1, 0.1899 cm−1 1.6421 Å, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00162446
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Hβ luminosities of planetary nebula central stars (1994)
    Springer
    Astrophysics and space science 222 (1994), S. 147-155 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The determination of the luminosities of planetary nebula central stars from Hβ nebular fluxes is investigated. A correlation is obtained with the luminosities derived from independent stellar parameters. An average scaling factor is determined for Hβ luminosities of optically thick nebulae, as well as correlations of this parameter with the Zanstra He II and H I temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627089
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  • 3
    Electronic Resource
    Electronic Resource
    Gravity Distances of Planetary Nebulae (1997)
    Springer
    Astrophysics and space science 249 (1997), S. 341-352 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recent work on the PN classification scheme initially proposed by Peimbert has shown that type I and non-type I objects have markedly different properties. Type I PN have He and N enrichments, lower heights relative to the galactic plane, and lower peculiar velocities, while non-type I nebulae have normal abundances and increasing heights and peculiar velocities. This implies some mass and age differences of the different types, which can be used in order to determine distances to disk PN. In this work, the behaviour of PN of different types on the log g× log Teff plane is explored, in view of the fact that central stars of different masses have different paths on this diagram. As a result, distances can be derived for some galactic PN, which can be compared with previous determinations. The possibility is discussed of establishing a statistical distance scale based on the population segregation of PN of different Peimbert types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1000450125547
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    On the possibility of the existence of NO+ in interstellar space (1980)
    Springer
    Astrophysics and space science 68 (1980), S. 87-97 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Frequencies are computed for transitions in the NO+ ion which are expected to occur in the millimeter and infrared regions usually covered by millimeter-wave and infrared astronomy. The emission cross-sections and spontaneous emission rates of the microwave transitions of NO+ ion are presented. The NO+ molecule is likely to be detectable in low-temperature sources whose state temperatures are not greater than 15 K. Transition probabilities and oscillator strengths for the Δv=1, 2, 3 and 4 vibration-rotation bands are derived from published theoretical dipole moment functions, obtained by an accurate multi-configuration self-consistent field procedure, in the1∑ ground state of NO+ ion. On the basis of binary gas phase reactions, the formation and destruction of NO+ in interstellar space are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00641645
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  • 5
    Electronic Resource
    Electronic Resource
    New kinematic distances of NGC 7009 and BD+30°3639 from UV and radio data (1995)
    Springer
    Astrophysics and space science 229 (1995), S. 203-213 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Measurements of the equivalent width of the interstellar Lymanα line from IUE spectra in the direction of the planetary nebulae NGC 7009 and BD+30°3639 are used to infer the H column density in these directions. Hydrogen 21 cm profiles are also used in connection with the ultraviolet data so that the expected rotation velocities and distances can be determined. The results are compared with recently published distances, in an attempt to distinguish between the “short” and “long” PN distance scales as applied to these objects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00626867
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  • 6
    Electronic Resource
    Electronic Resource
    Dissociation equilibrium constants of molecules of astrophysical interest (1983)
    Springer
    Astrophysics and space science 96 (1983), S. 205-212 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Dissociation equilibrium constants are computed for 53 molecules containing H, C, N, O, Mg, Si, S, and Fe in a range of temperatures of astrophysical interest. The results are obtained using recent molecular constants and are compared with previously published data. The equilibrium constants are approximated by an analytical expression and the fitting coefficients are supplied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00661954
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  • 7
    Electronic Resource
    Electronic Resource
    A model for the chemical evolution of the galaxy with refuses (1994)
    Springer
    Astrophysics and space science 211 (1994), S. 241-251 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A model is presented for the chemical evolution of the solar neighbourhood which takes into account three families of galactic objects, according to their condensation states: stars, refuses and gas. Stars are defined as all condensed objects with masses greater than or equal to the minimum mass which ignites hydrogen and which will give rise to an evolutionary track on the HR diagram to the left of Hayashi's limit; refuses include the remnants, which are compact objects resulting from stellar deaths, and the residues, which have masses not large enough to ignite hydrogen; gas is defined as the mass which can be condensed to form stars and/or residues. We have developed equations for the mass evolution of each family, and have studied the gas metallicity distribution within the framework of the instantaneous recycling approximation, adopting different initial conditions. In order to constrain the model parameters we have also used preliminary evaluations of comet cloud masses to investigate the role of the residues as sinks of heavy elements in the Galaxy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658227
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  • 8
    Electronic Resource
    Electronic Resource
    Abundances and radial gradients from disk planetary nebulae: He, N, C, and Cl (1994)
    Springer
    Astrophysics and space science 219 (1994), S. 231-247 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Chemical abundances of the elements He, N, C, and Cl are presented for disk planetary nebulae, comprising Peimbert types I, II, and III. Average abundances for these classes are determined and compared with the remaining abundances available. The presence of abundance gradients relative to hydrogen for disk nebulae is investigated in a region of about 8 kpc centered in the solar system. It can be concluded that the gradients of the ratios N/H, Cl/H, and probably C/H are similar to the O/H gradient, especially for type II objects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00628240
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  • 9
    Electronic Resource
    Electronic Resource
    Radial abundance gradients and the simple model for the chemical evolution of the Galaxy (1992)
    Springer
    Astrophysics and space science 196 (1992), S. 23-28 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The oxygen abundance gradient relative to hydrogen is considered, as derived for galactic Hii regions and type II planetary nebulae. The so-called ‘simple’ model for the chemical evolution of the Galaxy is shown to explain well the observed gradients, provided some reasonable assumptions are made regarding the gas distribution in the galactic disk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645238
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  • 10
    Electronic Resource
    Electronic Resource
    Space distribution and metallicities of globular clusters: the distance to the galactic centre (1993)
    Springer
    Astrophysics and space science 206 (1993), S. 285-300 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The system of globular clusters in the Galaxy is used in order to locate the position of the galactic centre and, consequently, to determine the galacto-centric distance of the Sun,R 0. The space distribution and metallicities of the whole sample of known globular clusters are taken into account, and the obtained results indicate that 8.6 〉R 0 (kpc) 〉 6.4. Analysis of a selected sample of clusters further suggests thatR 0 = 7.6 ± 0.4 kpc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658152
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