UXOR Information Page
The acronym for these stars comes from the class prototype, UX Orionis
and is due to Herbst, et al. (1994, AJ 108, 1906).
Dust within a few tenths of an AU of the star causes optical
polarization of the starlight (Grinin et al. 1991, ApSS 186, 283).
Clumps in the dust disk (clouds? comet tails?) cause irregular
occultations of the star, typically up to 2.5 magnitudes at V
(or 90% of the optical light). (Bibo & The 1991, A&AS 89, 319;
Grinin et al. 1991)
Light Curve for BF Ori and Light Curve for UX Ori
(courtesy Arantxa Maira, 1998, "Tesina", Universidad Autonoma de Madrid)
The stars have characteristic trends of the optical colors
with decreasing light: as the light begins to decrease, the star
gets redder, and then near minimum light it becomes very blue,
as light scattered by dust in the disk dominates the total signal.
Color-Magnitude Diagram for BF Ori and
Color-Magnitude Diagram for UX Ori (courtesy
Arantxa Maira, 1998, "Tesina", Universidad Autonoma de Madrid)
In the UV, the stellar spectrum resembles a heavily embedded
source at minimum light. These spectra were obtained by the International
Ultraviolet Explorer.UX Ori at
maximum and minimum light.
Stars with this variability, or with a history of this variability
have IR silicate emission features consistent with the presence of small, warm
amorphous, Mg-silicate grains ISO and Ground-Based
10 micron silicate profiles compared with lab. spectra
This document is part of the EXPORT Team Web Site
Updated:Tuesday, May 5, 1998.
