A 200 km s − 1 molecular wind in the peculiar carbon star VHya
نویسنده
چکیده
A molecular wind with an outflow speed in excess of 200 km s −1 has been found in the AGB carbon star V Hya. Observations of several molecular lines show that the circumstellar envelope is expanding at 15 km s −1 and is flattened and inclined to the line of sight. The fast wind appears to be expanding from the poles of the envelope, with the expansion speed increasing with distance from the star. V Hya may be in the very earliest stage of evolution beyond the AGB.
منابع مشابه
The circumstellar molecular envelope of HD 101584
CO radio line observations reveal a molecular gas envelope around the peculiar star HD101584 with characteristics very similar to those of wellknown young post-AGB objects. We estimate that there is at least 0.1 M of molecular gas, very likely remnant gas from a former AGB-envelope. This gas has been efficiently accelerated to very high velocities (>50 km s−1, and a significant fraction to >100...
متن کاملThe uncertainty in Galactic parameters
We reanalyse the measurements of parallax, proper motion, and line-of-sight velocity for 18 masers in high mass star-forming regions presented by Reid et al. (2009). We use a likelihood analysis to investigate the distance of the Sun from the Galactic centre, R0, the rotational speed of the local standard of rest, v0, and the peculiar velocity of the Sun, v⊙, for various models of the rotation ...
متن کاملar X iv : a st ro - p h / 95 10 12 0 v 1 2 3 O ct 1 99 5 1 THE VELOCITY GRADIENT IN THE PSEUDO
In this paper preliminary results are presented based on a study of the low and high resolution ultraviolet spectrum of the peculiar supergiant (post-AGB star) HD 101584. By a comparison of the low resolution spectrum (1200 − 3200Å) with standard stars, the star is classified as an A7I, indicating an effective temperature of 8150 K, where literature quotes spectral type F0I. The Doppler shift o...
متن کاملWebo 1: a Young Barium Star Surrounded by a Ring-like Planetary Nebula
WeBo 1 (PN G135.6+01.0), a previously unrecognized planetary nebula with a remarkable thinring morphology, was discovered serendipitously on Digitized Sky Survey images. The central star is found to be a late-type giant with overabundances of carbon and s-process elements. The giant is chromospherically active and photometrically variable, with a probable period of 4.7 days; this suggests that ...
متن کاملHe I 1 . 083 μ m emission and absorption in DG Tau : line excitation in jet , hot wind , and accretion flow 1
We present long-slit spectroscopy and spectro-astrometry of He I 1.083 µm emission in the T Tauri star, DG Tau. We identify three components in the He I feature: (1) a blueshifted emission component at v≃−200 km s −1 , (2) a bright emission component at zero-velocity with a FWZI of ∼500 km s −1 , and (3) a blueshifted absorption feature at velocities between −250 and −500 km s −1. The position ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1997