Quadrantid Meteor Research Articles

Radio-Echo Measurements of the Flux of the Quadrantid, Perseid and Geminid Meteor Streams

Radio-Echo Measurements of the Flux of the Quadrantid, Perseid and Geminid Meteor Streams

Physical Sciences: Effect of Sunrise on the Meteor Region

PREVIOUS observations at Sheffield of radio echoes from Quadrantid meteors have shown a marked increase in the numbers of echoes with enhanced duration (>2 s) some tens of minutes after sunrise on the echoing layer (unpublished work of T. R. Kaiser, T. F. Nicholson and L. M. G. Poole). During the 1972 Quadrantids this increase occurred at 0830 UT, about 60 min after layer sunrise at a time when the solar zenith angle at the layer was 91°.

A Radar Determination of the Right Ascension and Declination of the Quadrantid Meteor Stream

A Radar Determination of the Right Ascension and Declination of the Quadrantid Meteor Stream

9. The influence of exposure duration and trail orientation on photographic meteor spectra

The effects on photographic meteor spectra produced by an occulting shutter and by the geometric orientation of the trail with respect to the camera are considered. A Perseid meteor photographed with both an occulted and unocculted spectrograph shows that large changes in the relative intensity of spectral lines can be caused by a shutter. The strong wake spectrum of this meteor is studied and a classification of multiplets according to duration and wake intensity is presented. It is emphazised that a strong wake is produced by a coasting gas rather than by particles or droplets. The gas may coast an appreciable distance during the radiating lifetime of some multiplets.The spectrum of a bright Quadrantid meteor is used to show that long-duration multiplets are strongly enhanced when the orientation of the trail lengthens the effective path length of the wake column, i.e., the meteor is observed near its radiant. The abundance of calcium appears to be above average in this meteor.Multiple photographs of the λ5577 line of neutral oxygen have been secured showing a decay time in excess of 1·5 sec. The decay is more rapid at lower heights and it appears that the mechanism of excitation to the metastable level operates for an interval of about 0·1 sec.As more accurate photometry of meteor spectra is achieved it will be essential to give careful attention to all of these effects.

The duration distribution of radio-echoes obtained from underdense shower-meteor trains

The distribution in decay-times of radio echoes obtained from underdense trains formed by meteors associated with Perseid, Geminid and Quadrantid meteor showers has been measured for meteors in the radio-magnitude range 5.3 m to 6.8 m. The results indicate that ionization profiles are considerably shorter than predicted by the simple evaporation theory, that the geomagnetic field has an appreciable effect upon diffusion in meteor trains, and that the exponent n in the law ϱ 1 ∝ α 1 n (where α 1 is the maximum electron line density which occurs at a height where the atmospheric density is ϱ 1) could be slightly larger than the theoretical value of 1 3 . It is shown that these results can be explained in terms of the ablation of single grain meteoroids.

Photographic Quadrantid meteors

view Abstract Citations (12) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Photographic Quadrantid meteors Shelton, John W. Abstract Analysis of 57 photographic Quadrantid meteors indicates a mean radiant at a = 230?5, = 49?3 at the time of maximum activity on 2, 3, or 4 January (sun's longitude282?5, equinox 1950.0), and suggests a mean-radiant motion of 16 per day towards increasing right ascension and decreasing declination. The duration of the intense, central portion of the shower appears to be about 0.3 days, while there is some evidence that much weaker activity may extend from 1 to 13 January. The average residual distance of an individual radiant from the mean-radiant path at the instant of the meteor is about 1?5, which is abnormally large compared with the relation found between stream width and radiant scatter for 13 other showers, but this is reasonably explained by the orbit's close approach to Jupiter. Publication: The Astronomical Journal Pub Date: June 1965 DOI: 10.1086/109745 Bibcode: 1965AJ.....70..337S full text sources ADS |

On the regressional motion of the node of the Quadrantid meteor stream.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the regressional motion of the node of the Quadrantid meteor stream. Hamid, Salah ; Nagib, Mary Abstract The Quadrantid meteor stream has been studied recently by Hawkins and Southworth. From the determinations of times of shower maxima, as observed during the last 120 years, they found that the node of the stream is regressing at the rate of o?6/century. It is known that the secular perturbations of the planets on a meteor stream cause such regressional motion. The secular perturbations due to Jupiter and Earth have been computed numerically using Gauss's method. The orbital elements which were used in the computation are: The stream 3.66 0.72 282 170 72 Jupiter 5.202803 0.0484223 99.9 13.5 1.3 Earth 1.000000 0.016729 102.1 The Earth's effect on the motion of the stream S node is found to be almost negligible, amounting to o?ooo8/century. Jupiter's effect, - o? 3/century, accounts for almost half the observed motion. In computing Jupiter's effect, the trapezoidal rule of mechanical quadrature was applied, the independent variable taken to be the eccentric anomaly of the stream; 144 points equally distributed with respect to the eccentric anomaly were considered in the quadrature. As a numerical check for the small error of the quadrature, we compared two values of EWo sin ujo1. For E (eccentric anomaly) 00, ~0, 100,... = -3.1097377 2?5, 7?5, 12?5,... = -3.1097389 A stronomy Department Cairo University Faculty of Science Cairo, Egypt Publication: The Astronomical Journal Pub Date: October 1959 DOI: 10.1086/107942 Bibcode: 1959AJ.....64..333H full text sources ADS |

VARIATIONS IN THE INTRINSIC STRENGTH OF THE 1956 QUADRANTID METEOR SHOWER

The occurrence rate of meteoric signals, detected on a V.H.F. forward-scatter path, is analyzed for the time of the 1956 Quadrantid shower. The detection rate of the shower meteors is converted to an incidence rate, by use of the appropriate forward-scatter theory. The variation in the intrinsic strength of the shower is thereby determined, on an hour-to-hour basis, and it is compared with variations which have been obtained in other years by other methods. The comparison reveals a distinct secular shifting of the orbit of the Quadrantid meteor stream. It also illustrates the marked advantage of the new technique in assessing variations in the strengths of short-lived showers.

The Night Sky in January

NEW moon occurs on January 3d. 12h. 30m. U.T and full moon on January 17d. 14h. 46m. The following conjunctions with the moon take place: Jan 1d. 15h., Mercury 0·2° N.; Jan. 17d. 04h., Saturi 2° S.; Jan. 17d. 07h., Mars 2° N.; Jan. 24d. 11h. Jupiter 4° S. In addition to these conjunctions with the moon, Mars is in conjunction with Saturn or Jan. 22d. 17h., Mars being 4·4° N. Occupations on stars brighter than magnitude 6 are as follows Jan. 12d. 17h. 39·1m., 147 B Aries (D); Jan. 14d 01h. 57·8m., 85 H Tauri (D); Jan. 24d. 06h. 10·4m., 80 Virgo (R). The times are for Greenwich and (D) and (R) refer to disappearance and reappearance respectively. Mercury can be seen in the morning hours, rising at 6h. 25m. and 7h. 13m. at the beginning and middle of the month. Towards the end of the month the planet rises about the time of sunrise. Venus is too close to the sun during January for good observation, rising about 20 minutes before the sun on Jan. 1 and 15 minutes after the sun on Jan. 31. Mars, in the constellation of Cancer at the beginning of January, moving later into the constellation of Gemini, rises early in the evening and is well placed for observation throughout the night. The planet is in opposition with the sun on Jan. 14. Jupiter, in the constellation of Virgo, rises at 1h. 36m. on Jan. 1 and about midnight on Jan. 31. Saturn, in the constellation of Gemini, is visible throughout the night and does not set before the late morning hours. The earth makes its closest approach to the sun on Jan. 2. The Quadrantid meteor shower occurs during the first few nights of January.

The Night Sky in January

THE moon is full on January 2d. 15h. 42m. U.T. and new on January 16d. 21h. 32m. Lunar conjunctions with the planets occur on the following dates: Mercury on January 18d. 5h., Mercury 4°S.; Venus on January 18d. 13h., Venus 2° N.; Mars on January 24d. 8h., Mars 5° N.; Saturn on January 25d. 17h., Saturn 3° N.; Jupiter on January 27d. 10h., Jupiter 5° KT. On January 2 id. Ih. Mercury is in. conjunction with Venus, Mercury being 6.2° S. Mars, Jupiter and Saturn are well placed for observation during the night, and Saturn's ring system is well presented for observation. Venus can be seen in the evening hours in the west and does not set until 19h. in the middle of the month. The earth makes its closest approach to the sun on January 2. The Quadrantid meteor shower is active on the first few days of January: the radiant is at R.A. 5h. 24m., Dec. 51° N., but this shower is not usually very conspicuous. On January 26d. 22h. 17m. there will be an occultation of y Tauri, mag. 3-9. During the month the interval from sunsetto sunrise in the latitude of London shortens by 1h. 12m.

The Night Sky in January

IN the middle of the month at 22h, the full pageantry of the winter constellations is on the meridian; the segment of bright stars is- outlined by Capella (near the zenith), the Pleiades and Aldebaran, Rigel, Sirius, Procyon, Castor and Pollux, and so back to Capella. South of Orion's belt may be seen with the naked eye the hazy patch that marks the great gaseous nebula. The planet, Venus, is a brilliant object in the early evening sky; it will continue to increase in brightness until the middle of March. Venus is in conjunction with the moon on January 16d 15h and with Saturn on January 24d 2h after the two planets have set, their closest approach in the sky being 1-9 °. Mars is a morning star as well as Jupiter, the latter rising only about one hour before the sun in mid-January. The phases of the Moon are: Last Quarter, January 4d 14h: New Moon, January 12d 17h: First Quarter, January 19d 20h: Full Moon, January 26d 17h. The only bright star to be seen occulted from Greenwich is r Tauri (mag. 4.3) whose disappearance takes place on January 22d at 18h 0-6m. Members of the Quadrantid meteor shower may be looked for about January 2-3, the radiant point being at R.A. 15h 20m and Dec. 53 ° N. The times of minima of Algol accessible to observation are: January 10d 4h, 13d lh, 15d 21h, 18d 18h, 30d 5h.

The Quadrantids of 1903

OBSERVATIONS were made at Hampstead Heath on January 1, 3 and 4 for the Quadrantid meteors. During a combined watch of six hours, 57 meteors were seen, distributed thus:—