Alicia Aarnio

My previous work has included such topics as:
-Stellar variability
-Solar flares and X-ray phenomena
-Young stars and associations
For future research, I hope to integrate all of these topics to characterize the magnetic fields of young stars and the evolution of these fields by probing X-ray observations of T-Tauri stars. These data in concert with optical and infrared observations will provide crucial information regarding magnetic field-disk interactions and field line accretion during the formation process. I also intend to investigate the influence of the magnetic field on the rotation rate of young stars as a function of time, and believe it is of the utmost importance to understand stellar angular momentum loss with increasing age, which could be caused by these interactions.

A Survey for a Coeval, Comoving Group Associated with HD 141569
we explore the possible existence of a stellar association outside the Scorpius Centaurus star forming region. The first figure shows a map of the region searched, as well as some familiar neighboring associations, for context. This region was chosen based on the location of HD 141569, a triple star system. The A star of this system has a well-studied and intriguing circumstellar disk; all three stars are quite young, ~5 Myr. Young stars are generally not thought to occur in isolation, and so we set out to try to locate companions of similar age and space motions.

A spectroscopic survey of stellar X-ray sources within 30 degrees of HD 141569 (with common proper motions) was performed, with the result that a subset of the sample stars are lithium rich, and thus youthful.


We analyzed the space motions of the sample stars, finding that they were not consistent with a coherent, distinct group existing and associated with HD 141569.

In a surprising result, we found that the triple system which initially gained our interest appears to have formed in isolation- tracing the stars' positions back in time places them outside any presently known association or molecular cloud.

I spent two summers with the RHESSI team at GSFC in Greenbelt, MD, working on hard-xray imaging of solar flares. Here are a couple of samples of those images.

2002 flare with possible loop structure visible.

Loop structure on the solar limb.

Before doing any summer research, I did a final project in an observational class wherein I observed most of the period of a delta-Scuti variable, VZ Cancri. This is one of the ccd images I captured while observing.

Taken using a Meade 16" LXi and an SBIG ccd camera, Spring, 2002
Light curves to be posted soon...