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G O D D A R D A S T R O N O M Y C L U B
Issue 51 -- 1999 August
NEBULA is the official newsletter of the Goddard Astronomy Club (GAC), an employee organization of the Goddard Space Flight Center, Greenbelt, MD 20771. GAC meets the second Tuesday of each month, at noon in Building 21 Room 183A.
WWW page: http://gewa.gsfc.nasa.gov/~astro/gac.html.
President: Jean-Phillipe Olive 301-286-7510.
Editor: George Gliba, Code 660.1/Raytheon ITSS /|\ 301-286-1119
---------------------- LAST MEETING: July 13th ----------------------
Members talked about their experiences at the 10th annual Mason-Dixon star party held this past June. Jean-Phillipe Olive mentioned how some folks used their bare hands to warm up their secondary mirror to get rid of dew on a 20-inch Dob, and that it worked well. [I wouldn't want to try that stunt on a cold Winter night though! ED]. The possibility of having the ALCON 2001 in the DC area was mentioned at the AL Mid-East Regional meeting, which was held at the Mason-Dixon star party.
Club member Dr. Peter Chen, and 2 of his students (one his son), showed a robot that can pull a telescope around on a cart to different spots, not necessarily on the Moon. He also showed another of his revolutionary 1 meter telescope mirrors that you could easily hold with one hand!
Our treasurer, Keith Evans, volunteered to give a book report at the next meeting on "How Physics Began" which comes mostly from the book, "Newton's Clock: Chaos in the Solar System". Basically, physics started because people wanted to understand the motion of the planets, which he will explain at our next meeting.
-------------------- NEXT MEETING: August 10th --------------------
The next meeting will be held on August 10th. There will be a book report and discussion on "How Physics Began" by Keith Evans of GSFC.
The meeting will be in - NOTE CHANGE IN MEETING LOCATION on Tuesday, August 10th, at the usual time (noon to 1pm).
Some Summer Binocular Double Stars
While sweeping the star fields of Bootes about 10 years ago I came upon a beautiful pair of stars with great color contrast. I have not seen any mention of them in any of the guide books that I have read. The pair is known as Nu1 and Nu2 Bootis, also known as 52 and 53 Bootis. They are a wide 10.5 arc/mins apart, and can be found by following a straight line north of Delta Bootis to Mu Bootis, then continuing on about the same distance to Nu1 and Nu2 Bootis, another four degrees. They are both about 5th magnitude, and are of spec. type K5 III and A5 V, with estimated spectroscopic parallaxes of 100 and 38 parsecs respectively; so they are only an optical pair. The K5 III star is a spectroscopic binary with a period of about 60 years.
Nearby, Mu Bootis A and B are a physical double star system, but have very little color contrast, being spec. type F0 V and G1 V stars, about 108 arc/secs apart, and of 4.5 and 6.5 magn. They make a nice binocular object. They are about 95 light years away, according to their spectroscopic parallax. Mu Bootis B is also a double star, consisting of 7th and 7.5 magn. stars about 2 arc/secs apart, but a high power telescope will be needed to split them.
The faintest star in the quadrangle of stars that makes up the head of the constellation Draco, the Dragon, is one of the finest binocular double stars in the northern sky. It is called Nu Draconis, and consists of two 4.9 magn. stars 62 arc/secs apart, of spec. types A5 V and A6 V, that are neatly split in low power binoculars. The pair is considered a true physical binary, but no motion has been seen since it was first accurately measured by F.G.W. Struve in 1833. So, the orbital period is probably several thousand years. The A5 V star is also a spectroscopic binary with a period of 38.6 days. The distance to the Nu Draconis system is about 120 light years.
Another easy wide pair are Delta1 and Delta2 Lyrae, also known as 11 and 12 Lyrae. They are about 10 arc/mins apart, and are 5.6 and 4.3 magnitude in brightness. The color contrast is very nice, consisting of a B2.5 V and M4 II spec. type stars estimated to be 1150 and 800 light years away respectively. Delta2 Lyrae is an irregular variable star that varies from 4.3 to 5th magn.
There are also several other binocular doubles in this area, but they are not very colorful. There is Beta Lyrae, to the southwest, which has a 7.2 magnitude companion 47 arc/secs away. Both are B7 V stars. Beta Lyrae is a famous eclipsing binary with a period of about 13 days, and varies from 3.3 to 4.3 magnitude. It is easier to see the companion star in binoculars mounted on a tripod, when Beta Lyrae is at minimum, but a telescope will show it readily. To the north below Vega is another optical double star, Zeta Lyra, which isn't very colorful, but is a fine pair of stars of 4.4 and 5.7 magnitude about 44 arc/secs apart easily visible in binoculars.
Making a nearly equilateral triangle with Vega and Zeta Lyrae is Epsilon Lyrae, which consists of two stars of A4 V and A8 V spec. type easily visible in binoculars making an optical pair. However, each of these stars in turn is a true physical double, having F1 V and F0 V companions, but a telescope is needed to see them. They were discovered by William Herschel. When I was 13 years old, I remember easily spliting the major stars of Epsilon Lyrae without optical aid, but my eyes aren't that sharp anymore. See if you, or a child you know, can split them. They are about 3.5 arc/mins apart.
A famous optical triple star for binoculars is one named Omicron1 Cygni. It makes a naked-eye pair with Omicron2 Cygni a few degrees west of Deneb. It is a K2 II and B6 V star, of 3.8 and 7th magnitude, with a seperation of about 107 arc/secs, and a 5th magnitude A3 V star 338 arc/secs away that makes a very nice color contrast. The K2 II star is also an eclipsing binary, with the long period of 10.42 years. During its two month eclipse, it dims by about a half magnitude. The next eclipse will be around April 6, 2001. Interestingly, the star Omicron2 Cygni is also an eclipsing binary with a period of 3.15 years, but it only fades a couple tenths of a magnitude.
Another similar color contrast pair, is the famous double star Albireo, or Beta Cygni, located at the end of the northern cross in Cygnus, which can also be just split with good binoculars. Albireo may also be an optical, and not a physical double star. It consists of a K3 II and B8 V star, about 34.5 arc/secs apart. making it a difficult object with most binoculars, but an easy object with almost any telescope. It is estimated to be about 400 light years distant, and resides in a beautiful Milky Way star field.
References
The Observer's Sky Atlas - E. Karkoschka - 1990
Sky Catalogue 2000.0 Vol. 1 - A. Hirshfeld, R. Sonnott, F. Ochsenbein - 1991
Burnham's Celestial Handbook - Robert Burnham Jr. - 1978
Good Year For The Perseid Meteor Shower
Conditions are ideal this year for the annual Perseid Meteor Shower, which will peak for us the morning of August 12/13. Since the parent comet P/Swift- Tuttle was at perihelion in 1992, the Perseids have shown double maxima, but only the second, or traditional maximum will be visible from here. Under good conditions, away from major light pollution, a single observer can expect to see up to 50 meteors per hour, or more, before dawn on the morning of August 13th. So be sure to get out and watch the Perseids if it is clear. Perseids can also be seen, in somewhat diminished numbers, for several days before and after this date.
Taken from CCNet DIGEST, 16 July 1999
Possible Player In Origins Of Life? by - Andrew Yee (University of Hawaii)
A University of Hawai'i researcher has found a new form of pure carbon in a Mexican Meteorite.
A University of Hawai'i researcher and her colleagues from the NASA Space Science Division have confirmed that a new form of carbon previously made in the laboratory also exists in nature. The finding indicates that the pure carbon molecules known as fullerenes could have been a factor in the early history of Earth and might even have played a role in the origin of life.
University of Hawai'i at Manoa organic geochemist Luann Becker and NASA colleagues Theodore E. Bunch and Louis J. Allamandola discovered the presence of fullerene carbon molecules in the 4.6-billion-year-old Allende meteorite, which has been of interest to many scientists since it landed in Mexico three decades ago.
The scientists' report will appear in the July 15 issue of the British journal Nature. Becker shared their findings with fellow scientists during the triannual meeting of the International Society on the Origins of Life this week in San Diego, Calif.
"It's not every day that you discover a new carbon molecule in nature; that's what makes this interesting," Becker says. "If it played a role in how the earth evolved, that would be important."
Fullerenes are soccer-ball shaped molecules (hence their name, which honors geodesic-dome designer Buckminster Fuller) of 60 or more carbon atoms. Their discovery in 1985 as only the third form of pure carbon (along with diamonds and graphite) earned U.S. scientists Robert F. Curl Jr. and Richard E. Smalley and British researcher Harold Kroto the 1996 Nobel Prize in Chemistry. The trio accidentally synthesized these three-dimensional forms of carbon molecules in the laboratory while trying to simulate the high-temperature, high-pressure conditions in which stars form.
Scientists hypothesized that fullerenes also exist naturally in the universe. Becker, who earlier discovered the presence of fullerenes in deposits at the site of the Sudbury impact crater in Ontario, Canada, and her colleagues were able to document naturally occurring fullerene by exploiting a unique property characteristic of organic molecules. Unlike their pure-carbon cousins, which maintain a solid state, fullerenes can be extracted in an organic solvent.
Becker crushed a piece of the Allende meteorite, demineralized the sample with acids, and used the organic solvent to extract fullerenes from the residue. The scientists found not only the C60 and C70 molecules believed to be most prevalent, but also significant quantities of C100 to C400 molecules. This is the first discovery of higher fullerenes in a natural sample.
Because the multiple atoms in the molecule form a hollow, closed cage that can trap gasses inside, they may have delivered from their stellar birthplace both the carbon that is an essential element to life and the volatiles that contributed to the planetary atmospheres needed for the origin of life. At the very least, the molecules and their contents will tell scientists more about the early solar nebula or presolar dust existing when meteorites like Allende were formed.
The research is supported by a grant from the NASA Cosmochemistry Program.