The M.A.S. Newsletter

Journal of the Mauritius Astronomical Society

August 2000

The Next Meeting:

The next meeting will be due Thursday 10^th of August for a visit to the Mauritius Radio Telescope (MRT) at Bras d'Eau. We shall be meeting at 17:00 at Collège du Saint Esprit, from where we will drive to Bras d'Eau. Members wishing to offer a place in their vehicle are kindly requested to inform us at the following:

Mr. Ricaud Auckbur: 466 5932

Mr. Bhasker Desai: 454 1472

Myself:                         686 4396

Members wishing to come on that date but not having their own means of transport are also kindly requested to inform us (above) so that the necessary arrangements be made. Note that the meeting of the 25^th of August has been cancelled

The sky this month:

The a-Capricornids, which often produces long slow fireballs, reaches peak activity on the night of Wednesday the 2^nd of August. It is best observed from 00:00 to 04:00 on Thursday. Another shower, the i-Aquarids peaks on Sunday the 6^th of August. The Moon will not interfere with both showers. Unfortunately, both showers have a low Zenithal Hourly Rate (ZHR) of less than 10. The i-Aquarids shower is rich in faint meteors. The radiant (i.e the point among the stars from which the trails of the meteors appear to come) of both these showers are very high in our sky at the time of peak activity.

Shining brightly at magnitude - 3.9, Venus is back in the evening sky. On the 20^th of August it is in the constellation of Leo and sets at 19:21. The planets Jupiter and Saturn are both in the constellation of Taurus between the Hyades and the Pleiades. On the 20^th, Saturn rises at 00:37 while Jupiter at 01:14.

Comet LINEAR (C/1999 S4):

As from the beginning of August the fading comet can be seen best from the southern hemisphere. Southern observers with access to a small telescope are in for a treat on August 20th when the comet passes close to the Sombrero galaxy (M104). From Mauritius LINEAR S4 will pass right in front of M104, affording an opportunity for truly unique astrophotos. The map, shows the western sky on the 15^th of August at 19:00. The approximate position of the comet during the month of August is also shown relative to the constellations. Note that the comet is too faint (above magnitude 6) to allow for naked eye observation. With a pair of binoculars, one can expect to see up to magnitude 10. On the map below the expected magnitude is shown in brackets ( ) next to the date. Remember, the higher the magnitude number, the dimmer the comet! Good luck!

News:

Astronomers announced Tuesday 18^th July that they have seen for the first time a flare from a brown dwarf, a class of failed star thought to be free of such activity. In a paper to be published in the July 20 issue of Astrophysical Journal Letters, a group of astronomers reported that brown dwarf LP 944-20 suddenly brightened at x-ray wavelengths during a 12-hour observation by the Chandra X-ray Observatory December 15. The flare was likely triggered by activity beneath the surface of the dwarf, 60 times as massive as Jupiter. "The flare was a bonus," Gibor Basri of the University of California Berkeley said. "We've shown that older brown dwarfs don't have coronae, but the flare tells us they still have magnetic fields and also that subsurface flares occasionally punch through into the atmosphere."

Serge Florens, Secretary

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