منابع مشابه
Long term disc variability in the Be star o Andromedae
We present 18 years of high resolution and S/N Hα spectroscopy of the Be shell star o And, obtained between 1985–2002. Spectra taken during late 1985 show a pure photospheric profile, with disc re-formation commencing in 1986; a process that is found to occur over long timescales (∼103 days). Analysis of the evolution of the properties of the Hα shell profile suggest that the disc kinematics ar...
متن کاملRx J1856.5-3754: Bare Quark Star or Naked Neutron Star?
Recent Chandra observations have convincingly shown that the soft X-ray emission from the isolated neutron star candidate RX J1856.5-3754 is best represented by a featureless blackbody spectrum, in apparent contrast with the predictions of current neutron star atmospheric models. Moreover, the recently measured star distance (≈ 120−140 pc) implies a radiation radius of at most ∼ 5−6 km, too sma...
متن کاملTiming the Nearby Isolated Neutron Star Rx J1856.5−3754
RX J1856.5−3754 is the X-ray brightest among the nearby isolated neutron stars. Its X-ray spectrum is thermal, and is reproduced remarkably well by a black-body, but its interpretation has remained puzzling. One reason is that the source did not exhibit pulsations, and hence a magnetic field strength—vital input to atmosphere models—could not be estimated. Recently, however, very weak pulsation...
متن کاملOptical Observations of the Isolated Neutron Star RX J0720.4−3125
RX J0720.4−3125 is an unidentified bright soft X-ray source which shows pulsations at a 8.39 s period and has a thermal spectrum. We present deep B and R band images of its X-ray localization. We find one possible counterpart in the X-ray error box, with magnitudes B = 26.6±0.2 and R = 26.9±0.3. The very high X-ray to optical flux ratio confirms that this object is an isolated neutron star. We ...
متن کاملTHE AGE OF THE DIRECTLY IMAGED PLANET HOST STAR k ANDROMEDAE DETERMINED FROM INTERFEROMETRIC OBSERVATIONS
κ Andromedae, an early-type star that hosts a directly imaged low-mass companion, is expected to be oblate due to its rapid rotational velocity (v sin i=∼162 km s). We observed the star with the CHARA Array’s optical beam combiner, PAVO, measuring its size at multiple orientations and determining its oblateness. The interferometric measurements, combined with photometry and this v sin i value a...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 1910
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.19101840107