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Distance determination to PNe using the extinction-distance method

Published online by Cambridge University Press:  30 August 2012

Silvana G. Navarro
Affiliation:
Instituto de Astronomía y Meteorología, Universidad de GuadalajaraAv. Vallarta 2602, Col. Arcos Vallarta, Guadalajara, Jal., México email: [email protected] Instituto de Astrofísica de CanariasVia Láctea s/n, La Laguna, Tenerife, España, email: [email protected], [email protected]
Romano L. M. Corradi
Affiliation:
Instituto de Astrofísica de CanariasVia Láctea s/n, La Laguna, Tenerife, España, email: [email protected], [email protected]
Antonio Mampaso
Affiliation:
Instituto de Astrofísica de CanariasVia Láctea s/n, La Laguna, Tenerife, España, email: [email protected], [email protected]
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Abstract

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We present individual distances to three PNe: NGC 6537, NGC 6781 and NGC 7027, determined by the extinction-distance method. These objects are part of a larger sample (35) of PNe that we observed at ORM. In order to apply this method, and to obtain accurate distances, we determined the spectral type of 40 to 60 stars in the line of sight of each PNe. This implied the necessity of classifying few thousands of stellar spectra with S/N ratio between 10 and 60. To solve such need we developed an ANN system to perform automatic spectral classification which could classify spectra with S/N ratio as low as 20 with an accuracy better than 2 spectral subtypes. In this poster we compare the accuracy of such distances with previous distance determinations using other methods. We conclude that it is possible to use this method to obtain the distance of a large number of PNe with better precision.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2012

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