Radio Continuum and Recombination Line Observations of the Polypolar Planetary Nebula NGC 2440

نویسندگان
چکیده

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Spatially - Resolved O II Recombination Line Observations of the Ring Nebula , NGC 6720

We present new long-slit CCD spectra of O II permitted lines and [O III] forbidden lines in the Ring Nebula NGC 6720. These observations provide spatiallyresolved information on both O II and [O III] over the 70 diameter of the main shell. We find significant differences in the spatial distribution of the O II lines and [O III] λ4959. The [O III] emission follows the Hβ emission measure, peakin...

متن کامل

The tetra - lobed planetary nebula NGC 1501

Direct imagery and long-slit, spatially resolved echellograms of the high excitation planetary nebula NGC 1501 allowed us to study in detail the expansion velocity field, the physical conditions (electron temperature, electron density, ionization) and the spatial distribution of the nebular gas. An electron temperature of 11500 K and a turbulence of 18 km s−1 are derived by comparing the Hα and...

متن کامل

Observations and 3 D photoionisation modelling of the Wolf - Rayet planetary nebula NGC 1501

Deep optical spectra of the high excitation planetary nebula NGC 1501 and its W04 central star are presented. A recombination line abundance analysis of the central star's emission-line spectrum yields He:C:O mass fractions of 0.36:0.48:0.16, similar to those of PG1159 stars. A detailed empirical analysis of the nebular collisionally excited line (CEL) and optical recombination line (ORL) spect...

متن کامل

The 3 – D ionization structure of NGC 6818 : a Planetary Nebula threatened by recombination ⋆

Long-slit NTT+EMMI echellograms of NGC 6818 (the Little Gem) at nine equally spaced position angles, reduced according to the 3-D methodology introduced by Sabbadin et al. (2000a,b), allowed us to derive: the expansion law, the diagnostics and ionic radial profiles, the distance and the central star parameters, the nebular photo-ionization model, the 3-D reconstruction in He II, [O III] and [N ...

متن کامل

Imaging and Spectroscopy of the Planetary Nebula NGC 6778

We present narrow-band images and long-slit echelle spectra of the planetary nebula (PN) NGC6778. The data show this PN as bipolar, with a very prominent low-excitation equatorial toroid, highexcitation lobes and two pairs of collimated outflows. Morphologically, the pairs of outflows are different from each other; one is linear and oriented along the bipolar axis, the other presents an S-shape...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: The Astrophysical Journal

سال: 1999

ISSN: 0004-637X,1538-4357

DOI: 10.1086/307059