The Large-Scale Distribution of Neutral Hydrogen in the Galaxy

Burton, W. B.

doi:10.1007/978-1-4684-6240-1_4

Cited by 5 publications

(5 citation statements)

References 27 publications

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“…It is important to note that the ages determined in Table 3 are the ones given in Table 2 but scaled to the distance to the nebula. We have used the distances obtained from the Galactic rotation curves of Burton (1974) when possible, as these distances are considered to be the most reliable. In some cases, our data was out of the range covered by the rotational curves, and therefore the distance estimate was not viable through this method.…”

Section: Pn Agesmentioning

confidence: 99%

“…In Table 3, column (1) gives the PN name, column (2) the radial velocity, column (3) the kinematic age at 1 kpc obtained from the model fitting, column (4) the statistical distances taken from Acker et al (1992), column (5) the distances estimated from the galactic rotation curve (Burton 1974), and column (6) the distance used to estimate the kinematical age which is given in column (7).…”

Section: Pn Agesmentioning

confidence: 99%

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Kinematical Analysis of a Sample of Bipolar Planetary Nebulae

Dobrinčić

Villaver

Guerrero

et al. 2008

The Astronomical Journal

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We present the kinematics of a sample of bipolar planetary nebulae (PNs) which cover a wide range of observed morphologies and collimation degrees, from bipolar PNs (BPNs) with a marked equatorial ring and wide lobes to highly collimated objects. We use an empirical model in order to derive the expansion velocity, collimation degree, and inclination angle of the PN with respect to the plane of the sky. The equatorial expansion velocities measured in the objects in our sample are always in the low-to-medium range (3-16 km s −1 ), while their polar expansion velocities range from low to very high (18-100 km s −1 ). None of the objects in our sample, even those that show an extreme collimation degree, seem to be (kinematically) younger than 10 3 yr. We compare our results with the state-of-the-art theoretical models for the formation of BPNs. We find good agreement between the observed expansion velocities and numerical models that use magnetic fields with stellar rotation as a collimation mechanism.

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Section: Pn Agesmentioning

confidence: 99%

Section: Pn Agesmentioning

confidence: 99%

Kinematical Analysis of a Sample of Bipolar Planetary Nebulae

Dobrinčić

Villaver

Guerrero

et al. 2008

The Astronomical Journal

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“…• 2566 and b = 26. • 0070 we derived from Burton (1974), Fich et al (1989, and Hartmann et al (1997) N (H) = 4.246×10 24 cm −2 . Using N (H) = E B−V ×5.9×10 25 , we obtain E B−V = 0.072 and thus derive the following corrections:…”

Section: Resultsmentioning

confidence: 92%

New classification and basic stellar parameter of SW Equulei

Behre

Hünsch

2013

Astron Nachr

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We review the classification of the variable star SW Equulei, formerly classified as a close binary of the W UMa type with a period of 0.83632 d and components of spectral types O-A or F-G and later. New observations indicate that the light curve is not that of an eclipsing binary but of a pulsating star with a period half of the old value. Further examination shows that SW Equulei is a double mode star of the RRd Lyrae type with a fundamental period of P = 0.560727 d and an overtone of P = 0.4181777 d at a distance of ≈ 7.1 kpc.

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“…The kinematical ages given in column (4) of Table 1 were obtained assuming uniform nebular expansion and assuming that all the nebula are located at 1 kpc. To estimate the PN age in column (5), we have used combined distance values taken from the rotation curves of Burton (1974) and statistical distances given in the Acker et al (1992) ratios, are expected to be young. Among these PNe are He 2-428, M 4-14, M 2-48, and M 3-55.…”

Section: Analysis and Resultsmentioning

confidence: 99%

Kinematical analysis of Bipolar Planetary Nebulae

Dobrinčić

Villaver

Guerrero

et al. 2006

IAU

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Bipolar planetary nebulae (BPNe) offer a unique opportunity to test models that aim to reproduce the PNe morphologies. In particular, kinematic studies of BPNe allow a reconstruction of the 3D structure of the nebula, otherwise hidden in imaging studies. With this aim in mind we have obtained long-slit echelle spectra of a sample of PNe which cover the full range of observed bipolar morphologies, from elliptical to highly collimated. The analysis of our kinematical data reveals equatorial expansion velocities in the low to medium range (3 to 16 km s −1), while the polar expansion velocities range from 18 to 100 km s −1. We find that the kinematics of the PN K 3-46 can only be explained by a decrease in the expansion velocity with time. The kinematical ages, calculated by using distances estimated from Galactic rotation curves, when available, or by using statistical values, show that the BPNe in our sample-even those which show non-extreme collimation-appear to be young. We have compared our results with the latest theoretical models of BPN formation, and find good agreement between the observed expansion velocities and the numerical models that use magnetic fields coupled with stellar rotation as the collimation mechanism.

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The Large-Scale Distribution of Neutral Hydrogen in the Galaxy

Cited by 5 publications

References 27 publications

Kinematical Analysis of a Sample of Bipolar Planetary Nebulae

Kinematical Analysis of a Sample of Bipolar Planetary Nebulae

New classification and basic stellar parameter of SW Equulei

Kinematical analysis of Bipolar Planetary Nebulae

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