The Daytime May Arietids meteor shower
Key facts
- Peak
- around 16 May
- Active
- early May to early June
- Rate at peak (ZHR)
- very weak on radio; not visible by eye
- Speed
- about 25 km/s
- Radiant
- Aries (close to the Sun in the sky)
- Parent body
- Unknown
Dates shift slightly from year to year. This year's peak is in the events calendar.
The Daytime May Arietids are a slow, weak daytime shower in mid-May, one of the family of Aries showers that ends with the strong Arietids of June.
A shower in daylight. The radiant in Aries is only a few tens of degrees from the Sun in mid-May, so it is above the horizon almost entirely during daytime. The shower was found by radar, which detects the ionised trails meteors leave in the upper atmosphere.
What we know. The meteoroids enter at about 25 kilometres per second, on orbits similar to Earth's in direction. Radio observers list the maximum around 16 May. Long programmes of radio counting have not always found clear activity from this shower, so its strength in recent years is uncertain.
The parent. No parent body has been identified.
Not to be confused with. The Daytime Arietids, peaking around 7 June, are one of the strongest showers of the year and are a separate stream, linked to the Machholz complex of comets. The Epsilon Arietids, peaking around 9 May, are another separate weak stream. The three share a constellation but nothing else.
What to expect. Nothing by eye. By radio, perhaps a small addition to the meteor counts in mid-May.
How to observe. A radio receiver tuned to a distant transmitter detects meteor echoes at any time. Running it through May and June shows how activity rises as Earth passes through the spring daytime streams and then jumps in early June with the Arietids and Zeta Perseids.
The May Arietids illustrate a general rule: many showers that are listed in catalogues are weak, and only careful, long-term records can show whether they are active in any given year.
Viewing tips
- Use a radio receiver; the radiant is too close to the Sun to watch.
- Record echoes through May and June to see the build-up to the Arietids.
- Keep the same equipment and settings so counts can be compared.
- Never look towards the Sun when observing near dawn.
- Remember the strong June Arietids are a different stream.