The UCD1+ controlled vocabulary Version 1.23

Martinez, A. Preite; Derriére, S.; Delmotte, N.; Gray, Norman; Mann, Robert W.; McDowell, Jonathan; Glynn, Thomas Mc; Ochsenbein, F.; Osuna, P.; Rixon, G.; Williams, Roy E.

doi:10.5479/ads/bib/2007ivoa.spec.0402m

Cited by 15 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note, however, and by contrast, that observed values of T Z (He II) are often in agreement with central star colour temperatures T C , and energy balance temperatures T EB (see, e.g. Preite-Martinez & Pottasch 1983;Gathier & Pottasch 1989).…”

Section: T H E R E L At I O N B E T W E E N T Z a N D T Effmentioning

confidence: 91%

The relation between Zanstra temperature and morphology in planetary nebulae

Phillips¹

2003

Monthly Notices RAS

View full text Add to dashboard Cite

We have created a master list of Zanstra temperatures for 373 galactic planetary nebulae based upon a compilation of 1575 values taken from the published literature. These are used to evaluate mean trends in temperature for differing nebular morphologies. Among the most prominent results of this analysis is the tendency for η=TZ(He ii)/TZ(He i) to increase with nebular radius, a trend which is taken to arise from the evolution of shell optical depths. We find that as many as 87 per cent of nebulae may be optically thin to H ionizing radiation where radii exceed ∼0.16 pc. We also note that the distributions of values η and TZ(He ii) are quite different for circular, elliptical and bipolar nebulae. A comparison of observed temperatures with theoretical H‐burning tracks suggests that elliptical and circular sources arise from progenitors with mean mass 〈MPG〉≅ 1 M⊙ (although the elliptical progenitors are probably more massive). Higher‐temperature elliptical sources are likely to derive from progenitors with mass ≅2 M⊙, however, implying that these nebulae (at least) are associated with a broad swathe of progenitor masses. Such a conclusion is also supported by trends in mean galactic latitude. It is found that higher‐temperature elliptical sources have much lower mean latitudes 〈b〉 than those with smaller TZ(He ii), a trend which is explicable where there is an increase in 〈MPG〉 with increasing TZ(He ii). This latitude–temperature variation also applies for most other sources. Bipolar nebulae appear to have mean progenitor masses ≅2.5 M⊙, whilst jets, Brets and other highly collimated outflows are associated with progenitors at the other end of the mass range (〈MPG〉∼ 1 M⊙). Indeed it is possible, given their large mean latitudes and low peak temperatures, that the latter nebulae are associated with the lowest‐mass progenitors of all. The present results appear fully consistent with earlier analyses based upon nebular scale heights, shell abundances and the relative proportions of differing morphologies, and offer further evidence for a link between progenitor mass and morphology.

show abstract

Section: T H E R E L At I O N B E T W E E N T Z a N D T Effmentioning

confidence: 91%

The relation between Zanstra temperature and morphology in planetary nebulae

Phillips¹

2003

Monthly Notices RAS

View full text Add to dashboard Cite

show abstract

“…The stellar temperature corresponds to the Zanstra temperature of HeII. Values for T * are taken from the literature (Kaler 1983;Preite-Martinez & Pottasch 1983;Pottasch 1984;Shaw & Kaler 1985;Gathier & Pottasch 1988;Gathier & Pottasch 1989;Gleizes, Acker, & Stenholm 1989;Kaler & Jacoby 1989;Shaw & Kaler 1989;Kaler, Shaw, & Kwitter 1990;Stanghellini, Corradi, & Schwarz 1993).…”

Section: Introductionmentioning

confidence: 99%

Are He and N Abundances in Type I Planetary Nebulae as High as Empirically Derived?

Gruenwald¹,

Viegas²

1998

ApJ

View full text Add to dashboard Cite

Type I planetary nebulae (PNe) are defined as those with high He and N abundances (Peimbert & Torres-Peimbert 1983). These objects present in general bipolar geometries and have high stellar temperatures (Corradi & Schwarz 1995, Torres-Peimbert & Peimbert 1997. In this paper we analyse the empirical methods for abundance determination in order to check if the He and N overabundances in Type I PNe are a consequence of a geometrical effect, due to the bipolarity, or the ionization stratification, due to the stellar temperature. For this, we obtain simulated spherically symmetrical as well as bipolar nebulae, using a 3D photoionization code. From the projected emission line intensities for: a) the whole nebula; b) for a slit crossing the nebula; as well as c) for different positions in the nebula, we applied the formulae used in the literature to obtain empirical abundances. These empirical abundances are then compared with the adopted ones. We show that empirical abundances depend on the particular line of sight covered by the observation and can simulate an overabundance and/or the presence of abundance gradients of He and N in planetary nebulae with high stellar temperature. The geometrical effects are also discussed. Systematic errors in abundance determinations by empirical methods are higher for the N/H ratio than for N/O. Thus, it seems better to use the N/O value when discussing N rich objects.

show abstract

“…G002.652+3.637 . This maser site is a new detection and is associated with IRAS 17349−2444, which was classified as a possible PN by Preite-Martinez (1988). This source shows double-horned profiles at both 1612 and 1667 MHz.…”

Section: G353810+1452mentioning

confidence: 79%

Accurate OH Maser Positions from the SPLASH Survey. III. The Final 96 deg²

Qiao

Breen

Gómez

et al. 2020

ApJS

View full text Add to dashboard Cite

We present high spatial resolution observations of ground-state OH masers achieved with the Australia Telescope Compact Array (ATCA). These observations targeted 253 pointing centres containing OH maser candidates at all four ground-state OH transitions identified in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) across 96 square degrees of the Southern Galactic plane (332. We detect maser emission towards 236 fields and suggest that 7 out of 17 non-detections are due to the slightly lower sensitivity of the ATCA observations, combined with some temporal variability. The superior resolution provided by the ATCA data has allowed us to identify 362 OH maser sites in the 236 target fields. Almost half (160 of 362) of these masers have been detected for the first time. Comparison between these 362 maser sites with information presented in the literature allowed us to categorize 238 sites as evolved star sites (66%), 63 as star formation (17%), eight as supernova remnants and 53 unknown maser sites (15%). We present analysis of the OH masers across the full SPLASH survey range (176 square degrees) and find that the detection rate of 1.7 GHz radio continuum sources (18%) is lower than that previously found at 8.2 and 9.2 GHz (38%). We also find that the velocity separations of evolved star sites with symmetric 1612 MHz maser profiles are generally smaller than those with asymmetric profiles.

show abstract

The UCD1+ controlled vocabulary Version 1.23

Cited by 15 publications

References 0 publications

The relation between Zanstra temperature and morphology in planetary nebulae

The relation between Zanstra temperature and morphology in planetary nebulae

Are He and N Abundances in Type I Planetary Nebulae as High as Empirically Derived?

Accurate OH Maser Positions from the SPLASH Survey. III. The Final 96 deg²

Contact Info

Product

Resources

About

The UCD1+ controlled vocabulary Version 1.23

Cited by 15 publications

References 0 publications

The relation between Zanstra temperature and morphology in planetary nebulae

The relation between Zanstra temperature and morphology in planetary nebulae

Are He and N Abundances in Type I Planetary Nebulae as High as Empirically Derived?

Accurate OH Maser Positions from the SPLASH Survey. III. The Final 96 deg2

Contact Info

Product

Resources

About

Accurate OH Maser Positions from the SPLASH Survey. III. The Final 96 deg²