61st Annual Meteoritical Society Meeting 5003.pdf

THE UPSILON PEGASID FIREBALL: EUROPEAN NETWORK 190882A. H. Povenmire, Florida Institute of Technology, 215 Osage Drive, Indian Harbour Beach FL 32937, USA.

On August 8, 1975, numerous faint, yellow- Pegasid meteors cannot produce sonic white meteors were observed radiating from the phenomena or meteorites [4]. Square of Pegasus. The radiant was near the The mass of the meteoroid which produced star, Upsilon Pegasi, at R.A. 350 degrees, Dec. this fireball was approximately 11.3 kg and +19 degrees. On August 7, 8, and 9, 1978, the would have had a spherical diameter of 43 cm. rates of the Upsilon Pegasids reached This meteoroid first became visible at 105.7 km, approximately 20 per hour. The broad reached maximum light at 74.7 km and ablated maximum seems to be on August 8, but could be completely at an altitute of 68.6 km. One later by several days. These meteors seem to probable Upsilon Pegasid spectra has been occur in clumps. That is, several will occur in a obtained and while blended, is thought to be of short period of time and then a significant lull Millman Type X which is sodium rich. A will occur with no activity [1]. literature search has found a total of five other On August 19, 1982, at 2:09:57 U.T., a double station Upsilon Pegasids which were magnitude -14.76 Upsilon Pegasid fireball originally reported as sporadics. All known occurred over the European Network and was comet orbits have been examined and the parent recorded by six of their cameras. The orbital comet of this meteor shower is unknown [4]. elements are as follows (2000.0) [2]: The radiant point on the celestial sphere of the parent comet is approximately R.A. 312 degrees, w = 303.9° Dec. +34 47’ (2000.0). i = 85.083° The period of this highly eccentric comet W = 144.3° orbit is unknown but Ceplecha has estimated q = 0.205 A.U. that its minimum orbital period is greater than e = 1.00 4700 years [2]. preatmospheric velocity = 51.5 km/s I wish to acknowledge the generous technical data and assistance given by Z. If this meteoroid had not contacted the Earth Ceplecha and P. Spurny of the European it would have reached perihelion on Network, Ondrejov Observatory, Czech approximately September 22 [3]. Republic. This type IIIB fireball had a double terminal References: [1] Povenmire H. (1980) burst with a duration of .71 second with a 2.0 Fireballs, Meteors and Meteorites, JSB second persistent train. This fireball was also Enterprises, Indian Harbour Beach, Florida. [2] observed visually and had a yellow-green color. Ceplecha Z. (1982) SEAN Bulletin, Vol. 7, No. Upsilon Pegasid meteors are snow-like, very 9, pp. 13–14, September 30, Smithsonian fragile and have a specific gravity of Institution, Washington, DC. [3] Spurny P. approximately 0.27 g/cm3. They are similar to (1995) personal communication. [4] Povenmire the Draconids and are thought to come from the H. (1996) IAPPP Comm. No. 65, pp. 28–31, outer portions of the comet nucleus. Upsilon Melbourne, Florida.