The Extraordinary Circumstellar Environment of U Equ

Details The Extraordinary Circumstellar Environment of U Equ The Extraordinary Circumstellar Environment of U Equ

Dec 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997hst..prop.7825b&link_type=abstract

HST Proposal ID #7825

Other

Hst Proposal Id #7825 Cool Stars Low-Mass Stars

Scientific paper

We have discovered a star with an optical spectrum unlike any ever observed. Deep, narrow absorption lines of non-photospheric TiO, AlO, and VO riddle the optical spectrum, and indicate a rotation temperature of 700 K. This cold gas is well below the grain condensation temperature, and it takes an unusual circumstellar environment to retain Ti and Al in the gaseous phase. AlO and VO are sometimes seen in the photospheres of only the coldest { 3000 K} M stars, but the underlying spectrum of U Equ seems to be that of a warm mid-G star { 4800 to 5000 K}. The IRAS 25/12 micron colors are consistent with optically thin dust, yet the LRS spectrum shows moderate silicate absorption which is normally associated with optically thick material. Based on the IRAS data, we suspect that the star has an edge-on disk, with extended material giving rise to optically thin emission. We recently obtained an infrared spectrum {1 to 2.4 micron} that includes prominent H2O absorption bands and shows the CO 2-0 overtone band without the bandhead structure normally present in spectra of cool stars, indicating that the material is cold. The absence of CH4 in the spectrum further indicates a low, non-photospheric density. Although there are other warm stars with edge-on disks, none has the cold molecular absorption that U Equ displays. Ground based J and K band {7"} images suggest a bipolar symmetry. With NICMOS we will be able to clearly identify the nature of the circumstellar material around this unusual star.

Affiliated with

Also associated with

No associations

Rating

The Extraordinary Circumstellar Environment of U Equ does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Extraordinary Circumstellar Environment of U Equ, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Extraordinary Circumstellar Environment of U Equ will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-896294