124 research outputs found
The TWA 3 Young Triple System: Orbits, Disks, Evolution
We have characterized the spectroscopic orbit of the TWA 3A binary and
provide preliminary families of probable solutions for the TWA 3A visual orbit
as well as for the wide TWA 3A--B orbit. TWA 3 is a hierarchical triple located
at 34 pc in the 10 Myr old TW Hya association. The wide component
separation is 1."55; the close pair was first identified as a possible binary
almost 20 years ago. We initially identified the 35-day period orbital solution
using high-resolution infrared spectroscopy which angularly resolved the A and
B components. We then refined the preliminary orbit by combining the infrared
data with a re-analysis of our high-resolution optical spectroscopy. The
orbital period from the combined spectroscopic solution is 35 days, the
eccentricity is 0.63, and the mass ratio is 0.84; although this
high mass ratio would suggest that optical spectroscopy alone should be
sufficient to identify the orbital solution, the presence of the tertiary B
component likely introduced confusion in the blended optical spectra. Using
millimeter imaging from the literature, we also estimate the inclinations of
the stellar orbital planes with respect to the TWA 3A circumbinary disk
inclination and find that all three planes are likely misaligned by at least
30 degrees. The TWA 3A spectroscopic binary components have spectral
types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as
a triple, is bound, and that its properties were shaped by dynamical
interactions between the inclined orbits and disk.Comment: Accepted to Ap
Origin of the Amphibian Chytrid Fungus
Histologic evidence indicates southern Africa as the origin of the amphibian chytrid fungus
Safety and Efficacy of Sertraline for Depression in Patients with CHF (SADHART-CHF): A randomized, double-blind, placebo-controlled trial of sertraline for major depression with congestive heart failure
Sertraline, a selective serotonin-reuptake inhibitor (SSRI), has demonstrated substantial mood improvement in patients with post myocardial infarction or with unstable angina. The impact of sertraline on the prognosis and depression of patients with chronic heart failure (HF) and co-morbid major depressive disorder (MDD) is unknown
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