WADHURST ASTRONOMICAL SOCIETY

NEWSLETTER MAY 2002

INDEX: MEETINGS, OTHER NEWS, CONTACTS,

MEETINGS

LAST MONTH

The last meeting was held on 8 May and the speaker was Kevin Apps on the subject of Extra solar planets. As some members are aware Kevin talked to the society last year on the same subject, so this evening's talk was an update on the situation since that time. Kevin started the talk with a recap on the last talk for the benefit of those members who were not at the previous meeting. This mainly consisted of how planets are found and what has been discovered so far. The number of discovered planets has of course increased since that time and the number found so far is nearly 80. At present the limitations mean that all of these planets are of a similar size to Jupiter and Saturn and all have orbital periods of less than 5 years. It is theoretically possible to locate planets that affect their star by about 2-3 meters per second; Jupiter affects the Sun by 13m/s so the future looks promising! Kevin then gave some details of some of the planetary systems that have been discovered so far. These included 47 Ursae Majoris (2 planets, both with circular orbits), Gliese 876 (2 planets with an orbital ratio of 2:1), Upsilon Andromedae (A 3 Planet system), HD 168443 (2 planets one of which is 17 Jupiter masses!) and HD 209458 (Where the planet transits the star and so the density has been found).

After a short break for refreshments, the talk continued with a look at how planets form. We have ideas of how the solar system formed and this theory has had to be tweaked to fit other systems found. It appears that after forming from the disk, planets must migrate in towards the Star. This has been observed and so it looks as though Jupiter may have formed further from the Sun than its present orbit. The eccentric orbits mainly found so far are thought to occur due to planets interacting gravitationally. When they do so three things can happen; they can collide (which is rare according to computer simulations), one can be thrown into the Sun (also rare) or one can be flicked out of the system (the most common). Therefore there may be many planets that are not orbiting a Star any more. It still looks as though our solar system may be unusual although it is still early days. Kevin also talked about the Kuiper belt, which is made up of leftovers from planetary formation, even this has been found in other systems (Epsilon Eridani).

Finally, Kevin looked at the future of planetary searches. For the moment searches will continue at the Keck , AAT, Magellan and Chile telescopes. There will also be a continuing search using photometric monitering which looks for planets transiting a Star. There are a number of space missions planned for the future including, Kepler (2006) which will look for Earth like planets transiting Stars, SIM (2009) the Space Interferometry Mission and TPF (2012) the Terrestial Planet Formation mission. Kevin finished the talk with a look at some slides of work by Lynette Cook who is a Space Artist.

NEXT MONTH

The next meeting is to be held on 12 June 7.30 for 7.45 as usual at Uplands Drama Studio. There is a change in the publicised speaker for this month. The speaker this month is Alan Drummond, who will speak on the subject of Open Clusters.  Andrew Robertson will speak to the society in July.
Tim has managed to arrange a few more future speakers; we will have a visit from Pam Spence later in the year and a meteorologist next year. Further details will follow as soon as available.
For the July meeting we will require a number of telescopes so that Andrew can go through the differences between each type. We are therefore looking for members who would be willing to bring their scope to the July meeting. We are looking for a Refractor, a Schmidt Newtonian, a Schmidt Cassegrain and a Newtonian. If any member is willing to bring theirs to the July meeting please make yourself known to the editor at the June meeting.

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OTHER NEWS

TREASURERS REPORT

As of the May meeting we had 48 paid up members. There are still unfortunately a number of previous members who have not yet paid their subscriptions for the year. It is hoped that there will be another raffle at the July meeting, as we have now accumulated some more prizes.

SPELDHURST FETE

As previously mentioned the society is due to have a presence at Speldhurst village Fete on 22 June. It is hoped that the society will be able to have a display of telescopes and some publicity boards at the event. One item that has been suggested is for a big diagram illustrating the Earths path around the Sun showing where we are at summer solstice (21 June). If anybody has any photos or drawings that are suitable for a display by the society please bring them to the June meeting or contact Tim or Ian.

NATIONAL ASTRONOMY WEEK 2003

The week will be 23-30 August 2003, which might seem a long way off, but plans will have to be put in place now. The timing of the week includes the date of the closest opposition of Mars ever in history. This will be the week for star parties, made easier by the fact that the schools are on holiday so more people will be able to stay up late. The SPA will be helping by producing a professional-quality audiovisual presentation for free loan by any group that requests it. Any ideas of events that the society could plan for the week need to be thought of now. The FAS is putting a website together that will hold all the details of events around the country. The website is at www.astronomyweek.org.uk

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CONTACTS

Chairman: Murray R. Barber 01892 654618 murray.barber@virgin.net

Secretary: Tim Bance 01732 832745 timbance@hotmail.com

Treasurer: Ian Reeves 01892 784255

Editor: Peter Bamblett 01732 368656 pbamblett@hotmail.com

Web site: Rob Cray rob@arcray.net

Publicity: Michael Harte 01892 783292 michael@greenman.demon.co.uk

Dir. of Obs.: Sean Tampsett 01892 667092 sean_tampsett@hotmail.com

Librarian: Joan Grace 01892 783721

Custodian of Equipment: Peter Prince 01892 836284

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Copy for the June edition of the Newsletter to reach the Editor by June 24 at the latest