منابع مشابه
The IMF of open star clusters with Tycho – 2
We studied the fields of nine nearby open star clusters based on the Tycho–2 catalogue. We determined membership probabilities for the stars in the cluster fields from the stellar proper motions and used the Tycho–2 photometry to compute the initial mass function (IMF) of the clusters from the main sequence turn-off point down to approx. 1M⊙. We found IMF slopes ranging from Γ = −0.69 down to Γ...
متن کاملA&a Manuscript No. the Tycho Star Mapper Background Analysis
The Hipparcos star mapper detector background signal has been analyzed in the Tycho reductions for contributions due to the diiuse galactic light. The methods are presented by which the contributions from the two elds of view of the telescope are separated after elimination of background variations due to the radiation environment (Van Allen belts). A complete sky background map, with a resolut...
متن کاملSome First Experiments on the Photometric Calibration of Schmidt Plates against the Tycho Catalogue
This paper presents our rst eeorts at photometri-cally reducing new GSC-II measures of Palomar II plates (J passbands) with Tycho for a 625 square degree test eld centred on the North Galactic Pole.
متن کاملTycho 2 stars with infrared excess in the MSX Point Source Catalogue
Stars of all evolutionary phases have been found to have excess infrared emission due to the presence of circumstellar material. To identify such stars, we have positionally correlated the infrared MSX point source catalogue and the Tycho 2 optical catalogue. A near/mid infrared colour criteria has been developed to select infrared excess stars. The search yielded 1938 excess stars, over half (...
متن کاملConstruction of Star Catalogue Based on Svm
The method of constructing navigation star catalogue always based on Magnitude Filtering Method (MFM). But it did not work well because of two typical disadvantages. On one side it would extract so many stars that there was redundancy in the catalogue. And on the other side it would generate “hole” in some area of celestial sphere. In this article, Support Vector Machine (SVM) was introduced in...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2002
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20011822