The Alpha Monocerotids is a
meteor shower
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extre ...
active from 15 to 25 November, with its peak occurring on 21 or 22 November. The speed of its meteors is 65 km/s, which is close to the maximum possible speed for meteors of about 73 km/s (see
Specific energy#Astrodynamics). Normally it has a low
Zenithal Hourly Rate (ZHR), but occasionally it produces much more intense meteor storms that last less than an hour: such outbursts were observed in 1925, 1935, 1985, and 1995. The 1925 and 1935 storms both reached levels passing 1,000 ZHR.
predicted the 1995 return based on the hypothesis that these outbursts were caused by the dust trail of a long period comet occasionally wandering in Earth's path due to planetary perturbations. During observations in southern Spain, assisted by a team of observers of the
Dutch Meteor Society
Dutch commonly refers to:
* Something of, from, or related to the Netherlands
* Dutch people ()
* Dutch language ()
Dutch may also refer to:
Places
* Dutch, West Virginia, a community in the United States
* Pennsylvania Dutch Country
People ...
, Jenniskens confirmed that the meteoroids were moving in a long-period comet orbit. The outburst of 1995 allowed researchers to determine the exact
radiant of the swarm and the
solar longitude
Solar longitude, commonly abbreviated as Ls, is the ecliptic longitude of the sun, i.e. the position of the sun on the celestial sphere along the ecliptic. It is also an effective measure of the position of the earth (or any other sun-orbiting bod ...
of its peak as well as to confirm the brevity of Alpha Monocerotid outbursts as less than one hour. The parent body, probably a long-period
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
, is unknown.
In 2019, Jenniskens and
Esko Lyytinen predicted an outburst starting around 04:50
UTC on November 22, 2019 (11:50 p.m.
EST November 21).
The meteor outburst was predicted to last for roughly 15 minutes, to reach 400 meteors per hour, similar to the rate of the 1995 outburst.
However, in the event, though the peak occurred at 05:00 UTC, the rate was much lower than predicted.
See also
*
List of meteor showers
Named meteor showers recur at approximately the same dates each year. They appear to radiate from a certain point in the sky, known as the radiant, and vary in the speed, frequency and brightness of the meteors. As of November 2019, there are 112 ...
References
External links
IAUC 6265: alpha MONOCEROTID METEORS 1995Meteor Outbursts from long-period comet dust trailsPECULIAR FEATURES OF a MONOCEROTID TV SPECTRA.On the dynamics of meteoroid streams
Meteor showers
November events
{{Meteor showers