While We Are Apart

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 June 13

Unexplained Dimmings in KIC 8462852
Illustration Credit: NASA, JPL-Caltech

Explanation: Why does star KIC 8462852 keep wavering? Nobody knows. A star somewhat similar to our Sun, KIC 8462852 was one of many distant stars being monitored by NASA’s robotic Kepler satellite to see if it had planets. Citizen scientists voluntarily co-inspecting the data along with computers found this unusual case where a star’s brightness dropped at unexpected times by as much as 20 percent for as long as months — but then recovered. Common reasons for dimming — such as eclipses by orbiting planets or stellar companions — don’t match the non-repetitive nature of the dimmings. A currently debated theory is dimming by a cloud of comets or the remnants of a shattered planet, but these would not explain data indicating that the star itself has become slightly dimmer over the past 125 years. Nevertheless, featured here is an artist’s illustration of a planet breaking up, drawn to depict NGC 2547-ID8, a different system that shows infraredevidence of such a collision. Recent observations of KIC 8462852 did not detect the infrared glow of a closely orbiting dust disk, but gave a hint that the system might have such a disk farther out. Future observations are encouraged and creative origin speculations are sure to continue.

Come to know the Summer Triangle

We in the Northern Hemisphere can see the Summer Triangle for part of the night at any time of the year. But seeing it in summer is the most fun! As suggested by its name, the Summer Triangle is most prominent during the summer season, for us at mid-northern latitudes. Although the Northern Hemisphere’s summer solstice won’t be forthcoming for another week, we can often see the Summer Triangle at evening dusk by mid-June. Seeing the Summer Triangle again and again on summer nights is a deep pleasure that adds to the enjoyment of this season. So, as dusk deepens into night on a warm June or July night, look eastward.

How to find the Summer Triangle. As night falls in June or July, look east for a sparkling blue-white star, whose name is Vega. Reigning at the apex of the celebrated Summer Triangle, Vega overwhelms as the brightest of the Summer Triangle’s three glorious stars, all bright enough to be seen from many light-polluted cities.

It’s difficult to convey the huge size of the Summer Triangle asterism – a star pattern that is not a constellation. At nightfall in summer, look for the brightest star in your eastern sky. That’s Vega, the brightest star in the constellation Lyra the Harp. Look to the lower left of Vega for another bright star – Deneb, the brightest in the constellation Cygnus the Swan and the third brightest in the Summer Triangle. An outstretched hand at an arm length approximates the distance from Vega to Deneb.

Look to the lower right of Vega to locate the Summer Triangle’s second brightest star. That’s Altair, the brightest star in the constellation Aquila the Eagle. A ruler held at an arm length fills the gap between these two stars.

Summer Triangle as a road map to the Milky Way. If you’re lucky enough to be under a dark starry sky on a moonless night, you’ll see the great swath of stars known as the Milky Way passing in between the Summer Triangle stars Vega and Altair. The star Deneb bobs in the middle of this river of stars that passes through the Summer Triangle, and arcs across the sky. Although every star that you see with the unaided eye is actually a member of our Milky Way galaxy, oftentimes the term Milky Wayrefers to the cross-sectional view of the galactic disk, whereby innumerable far-off suns congregate into a cloudy trail of stars.

Once you master the Summer Triangle, you can always locate the Milky Way on a clear, dark night. How about making the most of a dark summer night to explore this band of stars – this starlit boulevard abounding with celestial delights? Use binoculars to reel in the gossamer beauty of it all, the haunting nebulae and star clusters of a midsummer night’s dream!

Some see the Summer Triangle as a great big “V” for vacation, with Altair marking the point of the “V.” In summer, the Summer Triangle appears in the east at nightfall, high overhead after midnight and in the west at dawn. All night long on a summer night, the stars of the Summer Triangle – as if school kids on vacation – waltz amidst the streetlights of the Milky Way galaxy.

Summer Triangle as nature’s seasonal calendar. The Summer Triangle serves as a stellar calendar, marking the seasons. When the stars of the Summer Triangle light up the eastern twilight dusk in middle to late June, it’s a sure sign of the change of seasons, of spring giving way to summer. However, when the Summer Triangle is seen high in the south to overhead at dusk and early evening, the Summer Triangle’s change of position indicates that summer has ebbed into fall.

Bottom line: Coming to know the Summer Triangle, then seeing it again and again on summer nights, is a deep pleasure that adds to the enjoyment of this season.

Author

The Words of Confucius

Virtuous people often revenge themselves for the constraints to which they submit by the boredom which they inspire.

Your Daily Influences
June 13, 2016

The Eight of Wands Reversed
Delay seems probable. Jealousy may become a problem

Perthro
This may be a period of loneliness and stagnation you must fight through. This may not be a good time for you to take chances or indulge in any form of gambling.

Necklace of Charms
What you need in this aspect is a bit of understanding. You can find happiness in abundance if you understand and accept the differences of those with whom you share your life within this aspect.

Your Daily Influences represent events and challenges the current day will present for you. They may represent opportunities you should be ready to seize. Or they may forewarn you of problems you may be able to avoid or lessen. Generally it is best to use them as tips to help you manage your day and nothing more.