Conclusions about disk geometries in a few Herbig Ae/Be stars

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Session 9 -- Protostars, Young Stars and Stellar Accretion Disks
Display presentation, Monday, June 12, 1995, 9:20am - 6:30pm

[9.08] Conclusions about disk geometries in a few Herbig Ae/Be stars

A. Vaidya, R.E. Schulte-Ladbeck (U. Pittsburgh)

At the last summer meeting of the AAS, we presented observations of the linear polarization of a few Herbig Ae/Be (HAEBE) stars and candidates obtained at Pine Bluff Observatory. Since then, we have analyzed the data and have come to the following conclusions:

Intrinsic polarization is present in all of the HAEBE stars and candidates under investigation, namely HD 45677, HD 50138, HD 53367, HD 158643, and HD 200775. This conclusion is based on the variability of the linear polarization of either our data alone, or a combination of our data with broad-band polarimetry in the literature.

We have used the field-star method as well as the emission-line method to determine the interstellar foreground polarization. We intercompare the results, and also compare them with other values suggested in the literature. The choice of interstellar polarization is crucial for a determination of the geometry of the circumstellar material from the observed polarizations, and we discuss the possible values and their implications.

If we rank our program stars from ``almost certainly surrounded by a disk" to ``only weak indications for a disk", the list looks as follows: HD 45677, HD 50138, HD 158643, HD 200775, HD 53367.

This work was supported by a research experience for undergraduates grant through the AAS/NSF. We thank our colleagues at the University of Wisconsin who have made the data used in this project available to us. Pine Bluff Observatory is supported by NASA grant NAS5-26777.

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