An ALMA Dynamical Mass Estimate of the Proposed Planetary-mass Companion FW Tau C

Dynamical mass estimates down to the planet-mass regime can help to understand planet formation. We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm observations of FW Tau C, a proposed ~10 $M_{\rm Jup}$ planet-mass companion at ~330 au from the host binary FW Tau AB. We spatially and spectrally resolve the accretion disk of FW Tau C in ${}^{12}$CO (2-1). By modeling the Keplerian rotation of gas, we derive a dynamical mass of ~0.1 $M_\odot$. Therefore, FW Tau C is unlikely a planet, but rather a low-mass star with a highly inclined disk. This also suggests that FW Tau is a triple system consisting of three ~0.1 $M_\odot$ stars.Comment: Accepted for publication in ApJ

Submillimeter Array CO(2-1) Imaging of the NGC 6946 Giant Molecular Clouds

We present a CO(2-1) mosaic map of the spiral galaxy NGC 6946 by combining data from the Submillimeter Array and the IRAM 30 m telescope. We identify 390 giant molecular clouds (GMCs) from the nucleus to 4.5 kpc in the disk. GMCs in the inner 1 kpc are generally more luminous and turbulent, some of which have luminosities >10^6 K km/s pc^2 and velocity dispersions >10 km/s. Large-scale bar-driven dynamics likely regulate GMC properties in the nuclear region. Similar to the Milky Way and other disk galaxies, GMC mass function of NGC 6946 has a shallower slope (index>-2) in the inner region, and a steeper slope (index<-2) in the outer region. This difference in mass spectra may be indicative of different cloud formation pathways: gravitational instabilities might play a major role in the nuclear region, while cloud coalescence might be dominant in the outer disk. Finally, the NGC 6946 clouds are similar to those in M33 in terms of statistical properties, but they are generally less luminous and turbulent than the M51 clouds.Comment: Published in Ap

Resolving the H-alpha-emitting Region in the Wind of Eta Carinae

The massive evolved star Eta Carinae is the most luminous star in the Milky Way and has the highest steady wind mass-loss rate of any known star. Radiative transfer models of the spectrum by Hillier et al. predict that H-alpha is mostly emitted in regions of the wind at radii of 6 to 60 AU from the star (2.5 to 25 mas at 2.35 kpc). We present diffraction-limited images (FWHM ~25 mas) with Magellan adaptive optics in two epochs, showing that Eta Carinae consistently appears ~2.5 to 3 mas wider in H-alpha emission compared to the adjacent 643 nm continuum. This implies that the H-alpha line-forming region may have a characteristic emitting radius of 12 mas or ~30 AU, in very good agreement with the Hillier stellar-wind model. This provides direct confirmation that the physical wind parameters of that model are roughly correct, including the mass-loss rate of 10^-3 M_sun/yr, plus the clumping factor, and the terminal velocity. Comparison of the H-alpha images (ellipticity and PA) to the continuum images reveals no significant asymmetries at H-alpha. Hence, any asymmetry induced by a companion or by the primary's rotation do not strongly influence the global H-alpha emission in the outer wind.Comment: Published in ApJ

Flemingia macrophylla Extract Ameliorates Experimental Osteoporosis in Ovariectomized Rats

Flemingia macrophylla (Leguminosae), a native plant of Taiwan, is used as folk medicine. An in vitro study showed that a 75% ethanolic extract of F. macrophylla (FME) inhibited osteoclast differentiation of cultured rat bone marrow cells, and the active component, lespedezaflavanone A (LDF-A), was isolated. It was found that oral administration of FME for 13 weeks suppressed bone loss in ovariectomized rats, an experimental model of osteoporosis. In addition, FME decreased urinary deoxypyridinoline concentrations but did not inhibit serum alkaline phosphatase activities, indicating that it ameliorated bone loss via inhibition of bone resorption. These results suggest that FME may represent a useful remedy for the treatment of bone resorption diseases, such as osteoporosis. In addition, LDF-A could be used as a marker compound to control the quality of FME