Spatial distribution and galactic model parameters of cataclysmic variables
[ X ]
Tarih
2008
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
The spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been determined from a carefully established sample of 459 CVs. The sample contains all of the CVs with distances computed from the period-luminosity-colours (PLCs) relation of CVs which has been recently derived and calibrated with 2MASS photometric data. It has been found that an exponential function fits best to the observational z-distributions of all of the CVs in the sample, non-magnetic CVs and dwarf novae, while the sech(2) function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158 +/- 14 pc for the 2MASS J-band limiting apparent magnitude of 15.8. On the other hand, the vertical scaleheights are 128 +/- 20 and 160 +/- 5 pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found to be similar to 3 x 10(-5) pc(-3) Which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows an increasing trend toward higher space densities at low luminosities, implying that the number of short-period systems should be high. The discrepancies between the theoretical and observational population studies of CVs will almost disappear if for the z-dependence of the space density the sech(2) density function is used. (C) 2007 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Stars : cataclysmic variables, Stars : statistics, Stars : luminosity function, Galaxy : solar neighbourhood
Kaynak
New Astronomy
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
13
Sayı
3
