This page highlights a sample of Gemini related science results presented at the 211th meeting of the American Astronomical Society meeting in Austin Texas from January 7-11, 2008.
Figure 1: NIFS K-band spectrum of an O3 or O4 source showing photospheric lines of NIII and HeII.
NIFS Characterization of a Galactic Compact H II Region
Robert Blum (NOAO) and Peter McGregor (ANU) used the Near-Infrared
Integral Field Spectrometer (NIFS) + AO on Gemini North to study the
Galactic Ultra-Compact HII region G45.45+0.06. The NIFS data let Blum and McGregor identify several massive O-type stars which are responsible for the
ionization of the region. In the paper, “The Ionizing Stars of
the Galactic Ultra Compact HII Region G45.45+0.6” several sources were
characterized, including two embedded sources that exhibit CO bandhead
emission that is likely a signature of accretion from massive young
stellar objects within the complex.
Presentation number: 089.29 (PDF)
Figure 2: K-band spectrum of V568 Ori obtained with PHOENIX on Gemini South.
Magnetic Fields of T Tauri Stars in the Orion Nebula Cluster
Based on data from the Phoenix Spectrometer on Gemini South, Hao Yang and Christopher Johns-Krull of Rice University and Jeff Valenti of StSCI will present a poster titled, “The Magnetic Fields on T Tauri Stars in the Orion Nebula Cluster.” The team
observed Zeeman splitting in three Ti I lines to measure the strength of
the surface magnetic field of 15 T Tauri stars in the ~1 Myr old Orion
Nebula cluster. The resulting field strengths were then compared to
other clusters and associations of different ages (e.g. Taurus-Auriga)
to shed light on how these magnetic fields are generated.
Presentation number: 062.19
Explaining an Unusual Event by Eta Carinae
In the paper “What Happened to Eta Carinae in Early 2007,” PI John
Martin of the University of Illinois and an international team of
researchers used data from HST and Gemini that help explain the ~0.25
mag dimming of Eta Car in early 2007. During the fading event photometry
was gathered using WFPC2 and an optical spectrum was obtained with GMOS
on Gemini South, both sets of data help explain this unusual event.
Presentation number: 59.04 (PDF)
Figure 3: Plot of 19F vs. 12C abundances, with HE 1305+0132 marked by
the magenta square with error bars.
Fluorine Found in a Carbon-Enhanced Metal-Poor Star
High-resolution near-IR spectroscopy from Phoenix on Gemini South
let a team led by Simon Schuler (NOAO/CTIO) investigate the presence of
“Fluorine in the Carbon-Enhanced Metal-Poor star He 1305+0132.” This
star is the most Fe and O poor-star – by 1.5 orders of magnitude – for
which the abundance of 19F has been derived. The results of the analysis
imply that the atmosphere of He 1305+0132 has been polluted by mass-loss
from a companion AGB star. Also, the results imply that nucleosynthesis is extremely efficient in low-metallicity AGB stars, suggesting that AGB stars play a major role in the chemical evolution of the galaxy.
Presentation number: 131.12
Double-Peaked Water Lines in a Protoplanetary Disk
A research team led by Claudia Knez (University of Maryland) used
the mid-infrared spectrometer TEXES on the Gemini North telescope to
study water lines in the circumstellar disk around RW Aur A. The poster,
titled “TEXES High Resolution Observations of Water in a Proto-planetary
Disk” describes double peaked water lines that appear to be tracing the
gas in the disk inward of 1.1 AU at a temperature of between 450- 700 K.
Presentation number: 050.05