*4.1. Emission Line Nebulae*

One consequence of the high mass loss rate that LBVs posses and if present giant eruption is the formation of circumstellar nebulae. Many, however apparently not all LBVs are surrounded by a small nebula. Nebulae form by wind wind interaction of faster and slower winds during a S Dor cycle, while giant eruption LBVs nebula are the result of mass ejection in the eruption.

LBV nebulae predominantly contain stellar material, noticeable by the presence of stronger [N II] emission lines as a result of CNO processed material that was mixed up into the wind and/or ejecta of the star. During one of the first conferences devoted to LBVs in 1988, Stahl [49] reviewed on what was known about the nebulae around LBVs. Our current knowledge of LBV nebula is however still restricted mainly to nebula in our own galaxy and the Magellanic Clouds, only these nebulae are are spatially resolved and can be studied in detail.

A more recent study by Weis [50] show that the morphologies of the nebula are manifold. A signification fraction (on average 60%, 75% for galactic LBVs) show bipolarity. This bipolarity is either strong with a hourglass shape (i.e., *η* Car, HR Car, AG Car) or more weak in bipolar attachments, like Caps as seen in (i.e., WRA 751, R 127). Figure 4 shows one example of all so far known types of morphologies of either a galactic or LMC nebula. The true bipolar nature of the nebulae around AG Car has been identified by Weis [51]. Its hourglass structure is seen pol on and appears more spherical or rather boxy. Only by using high resolution Echelle spectra the kinematics revealed the true bipolar nature. Only one, the nebula around the LMC LBV R 143 is really irregular [52], this however is not surprising given the stars is situated in the middle of the 30 Doradus HII region. Spherical are S 61 and S 119 the latter showing signs of an outflow [53].

**Figure 4.** HST images of LBV nebulae sorted by morphology: hourglass AG Car [54], R 127 with bipolar attachments, weakly bipolar He 3-519 [55], spherical S 61 [52] and last in row irregular R 143 [52].

The list with parameters in Table 1 reveals that LBV nebulae are with only a few parsec rather small. The largest is with a diameter of about 4.5 pc the nebula around Sk-69◦ 279 in the LMC, the nebula shows an 1.7 pc extension in one direction, enlarging the nebula size to a dimension of 4.5 × 6.2 pc [56].

The the smallest (detected so far) are the Homunculus around *η* Carinae (see Section 4.4), the inner nebula around P Cygni (see section below) and the nebula around HD 168625 ([57], Weis et al. in prep) all with sizes of roughly 0.2 parsec. Note in that context that Weis [52] found for S Dor(LBV) nebula emission in the spectrum but it's physically to small to be spatially resolved (so far). The same is true for GR 290 in M 33 (see Maryeva this volume) and the galactic LBV W243 in Westerlund 1. They are therefore excluded from Table 1 and not marked bold for LBVs with nebulae in Table 2. The expansion velocities of LBV nebulae are a few km/s to 100 km/s [50,58,59] They are higher for *η* Car see section below.

**Table 1.** Parameters of Galactic and LMC LBVs and LBV candidates with an line emission (optical/NIR) nebulae. LBVs with dust nebulae only have been excluded here. In case the nebula has several spatially distinct parts (inner and outer regions) a slash is used for separation between them.

