June 18
The IAU's Choice
Sun Position
The Sun is in Gemini, declination near +23.4°. Northern days are still near their peak length; Virgo is settling toward the western horizon as summer takes hold.
Sky Highlight
No major meteor shower peaks today. The June Bootid meteor shower, associated with Comet 7P/Pons-Winnecke, has a variable and unpredictable peak around June 27 but can occasionally produce brief outbursts; it is worth monitoring in the last week of June.
Deep Sky Object
M58 (NGC 4579), a barred spiral galaxy roughly 62 million light-years away. M58 in Virgo is one of the brightest barred spiral galaxies in the Messier catalog and one of the few in the Virgo Cluster with a redshift indicating motion away from us rather than toward us. Still well-placed in the June evening sky from the Northern Hemisphere; in the west earlier each night now.
Featured Star
Minelauva (δ Vir) (also known as Auva) is a red giant (M3III) about 202 light-years away, the IAU's currently approved name for this star in Virgo, chosen from the medieval Arabic catalog tradition. A mildly variable cool giant, it pulses gently over weeks, its surface temperature too low to burn blue.
Around This Date
- June 18, 1983Sally Ride became the first American woman in space when Challenger launched on the STS-7 mission, a milestone that drew worldwide attention to NASA's astronaut selection program.
- June 18, 2009NASA launched the Lunar Reconnaissance Orbiter (LRO) and LCROSS missions to the Moon; LCROSS later confirmed the presence of water ice in permanently shadowed polar craters.
The IAU chose one name over another; the star itself keeps pulsing, indifferent to the committee.