ABSTRACT
The detection of circumstellar water vapour around the ageing carbon star IRC +10216 challenged the current understanding of chemistry in old stars, because water was predicted to be almost absent in carbon-rich stars. Several explanations for the water were postulated, including the vaporization of icy bodies (comets or dwarf planets) in orbit around the star, grain surface reactions, and photochemistry in the outer circumstellar envelope. With a single water line detected so far from this one carbon-rich evolved star, it is difficult to discriminate between the different mechanisms proposed. Here we report the detection of dozens of water vapour lines in the far-infrared and sub-millimetre spectrum of IRC +10216 using the Herschel satellite. This includes some high-excitation lines with energies corresponding to approximately 1,000 K, which can be explained only if water is present in the warm inner sooty region of the envelope. A plausible explanation for the warm water appears to be the penetration of ultraviolet photons deep into a clumpy circumstellar envelope. This mechanism also triggers the formation of other molecules, such as ammonia, whose observed abundances are much higher than hitherto predicted.
ABSTRACT
We constrain parity-violating interactions to the surface of last scattering using spectra from the QUaD experiment's second and third seasons of observations by searching for a possible systematic rotation of the polarization directions of cosmic microwave background photons. We measure the rotation angle due to such a possible "cosmological birefringence" to be 0.55 degrees +/-0.82 degrees (random) +/-0.5 degrees (systematic) using QUaD's 100 and 150 GHz temperature-curl and gradient-curl spectra over the spectra over the multipole range 200
ABSTRACT
In early 1983, OJ287 was seen to undergo an outburst in its optical and infrared emission1. Since then optical monitoring studies2-4 have shown a general decline in the source brightness, with considerable fluctuations. We have monitored the near-infrared emission since the outburst. The fluxes have fluctuated considerably, with the lowest recordings being an order of magnitude less than those measured during the outburst. We have found an excellent correlation between infrared flux and spectral index; as the source gets fainter the spectrum gets steeper, and vice versa. We interpret this in terms of outbursts being due to injection or reacceleration of electrons with a constant energy index which subsequently steepens as the electrons are affected by radiation losses.
