Publications of the MPIfR
Optical & Infrared
Interferometry Group
M. Schöller, W. Brandner, T. Lehmann,
G. Weigelt, and H. Zinnecker
Simultaneous Optical Speckle Masking and NIR
adaptive Optics Imaging of the 126 mas Herbig Ae/Be Binary Star NX
Puppis
Astronomy and Astrophysics, v.315, p.445-452 (1996)
Abstract
We present simultaneous optical and near-infrared high angular
resolution observations of the close Herbig Ae/Be binary star NX Pup
which is associated with cometary globule 1. The reconstructed images
have a diffraction-limited resolution of 62mas in V, 75mas in R
(speckle
masking reconstruction), and 115mas in H, 156mas in K (adaptive optics
+
post-processing). Compared to previous results we were able to derive
better estimates on spectral type and luminosity and hence put better
constraints on the evolutionary status (mass & age) of NX Pup A and
B: with NX Pup A of spectral type F0-F2 we estimate the spectral type
of
NX Pup B in the range F7-G4, masses of 2Msun_ and
1.6-1.9Msun_, respectively, and an age of 3-5Myr for both
stars. We discuss the implication of the new age determination on the
physical relation between NX Pup and the cometary globule. The
dynamical
lifetime of =~10^6^yr for cometary globule 1 suggests that cometary
globule 1 and the nearby cometary globule 2 represent transient
phenomena and are left overs of a larger molecular cloud which in turn
was the parental cloud of NX Pup A and B and finally got dispersed by
photoevaporation. The IR excess of NX Pup A can be modeled by a viscous
accretion disk, which is cut off at =~20AU from the star. NX Pup B has
a
smaller IR excess which indicates that there is less circumstellar
material present than around the primary.
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