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Ionized Photoevaporation Flows in H II regions and PNe
From proplyds to champagne flows, spanning 4 orders of magnitude in sizeand density, photoevaporation flows are ubiquitous in ion{H}{2} regions.Such flows are also found in planetary nebulae, in the form of cometaryknots, although in this case the flows are often``advection-dominated'', unlike the ``recombination-dominated'' flowsthat predominate in ion{H}{2} regions. The general properties of suchflows are discussed, with particular reference to recent results on theOrion proplyds and the Helix knots.
| Accurate Positions for MCG Galaxies
We have measured accurate celestial coordinates for 4741 extragalacticobjects, primarily drawn from a list of MCG galaxies with no recentlypublished accurate positions. The standard deviations in the newpositions depend slightly on the measurement method but are on the orderof 1.0" to 1.2". Standard deviations in the original MCG positions areconfirmed to be at the 1.5′-2.0′ level. These new positionswere integrated into NED in 1997 December.
| Study of the open cluster IC 1805
Photoelectric magnitudes and colours in the UBV system have beendetermined for 169 stars in IC 1805. The reddening is variable acrossthe cluster. The distance modulus to the cluster is estimated at 11.7 m.Star-formation activities are still in progress in the cluster region.
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