Venus, Jupiter get a little closer in sky
Last night was the peak of the Leonid meteor shower, which happens when Earth passes through the dust trails left behind by Comet 55P/Tempel-Tuttle. Unfortunately, the waning gibbous moon was up most of the night, washing out most of the meteors.
Next weekend you will see the two brightest planets, Venus and Jupiter, just a degree-anda-half apart (about a thumb width at arm’s length) from each other low in the southwestern sky in the evening. On Saturday evening, Venus will be right below Jupiter and on the evening of Nov. 24, Venus will be to the left of Jupiter. For the rest of November, the gap between Venus and Jupiter will widen as Venus closes in on Saturn. They’ll be next to each other in the second week of December.
CLEAR VIEW OF TRANSIT
It was a clear morning for the transit of Mercury on Nov. 11. Mercury was the lone black spot on an otherwise blank sun, which is currently in a time of relative non-activity called “solar minimum.”
The number of sunspots are a measure of the magnetic activity of the sun. When there is a lot of magnetic activity like flares, coronal mass ejections and huge prominences, there are also a large number of sunspots.
Usually, the solar activity ramps back up in a few years. The ebb and flow of solar activity has an average period of 11 years but it can be as short as eight years and as long as 14 years. The next solar cycle, around 2020, is expected to be the weakest one in 200 years, and this current solar minimum seems to bear that out.
MARS ON DISPLAY
“MARS One Thousand One,” the story of one possible mission to Mars, premieres Nov. 20 at the William M. Thomas Planetarium. Space reporter Miles O’Brien guides you through the first human mission to Mars — a daring 1,000-day mission to fly an international crew to the red planet and return them safely to Earth. The film continues the planetarium’s celebration of the 50th year anniversary of the first landing on the moon.
“MARS 1K1” is a bit longer than the other fulldome films shown at the planetarium, so the entire presentation, with the tour of the evening night sky using the Goto Chronos star projectorused with every presentation, will run from 7:30 to 9 p.m. Doors open at 7 p.m. and are locked when the show begins at 7:30 p.m. Go to bakersfieldcollege.edu/planetarium to get the links for information about buying tickets at the BC Ticket Office or online through Vallitix.
EXOPLANET CONFIRMED
In exoplanet news, a team of astronomers confirmed the existence of an exoplanet discovered by an amateur astronomer, Tadashi Kojima, in 2017 using the microlensing technique. Follow-up observations by a University of Tokyo research team were published in the Nov. 1 Astronomical Journal.
Of the over 4,000 exoplanets discovered so far, just 86 have been discovered with the microlensing technique. The exoplanet is slightly more massive than Neptune but its orbit is just 10 percent larger than Earth’s orbit. The exoplanet will be very cold, despite being so close to the star because the star is significantly cooler and dimmer than the sun.
When a star passes almost in front of another more distant star as seen from the Earth (the stars are not orbiting each other), the light from the distant star can be warped and focused toward us by the gravity of the nearer star to produce multiple images of the distant star or even a ring of light if they are aligned exactly right. This lensing effect is too small and the resolving powers of telescopes are too small to see the multiple images. The multiple images will blend together into a single blurry blob that is brighter than when the multiple images are not present (a microlens event). As the nearer star moves in front of the distant star, the nearer star’s blurry blob will appear to brighten and then dim as the nearer star moves out of alignment.
If the nearer star has a planetary system with an exoplanet at the right position, a smaller and briefer microlens event will happen superimposed on top of the star’s microlens. By looking for brief deviations in the otherwise smooth increase, then smooth decrease of a stellar microlens event, you could detect the presence of an exoplanet.
While most microlensing exoplanet searches look toward the galaxy center because of the larger number of stars in that direction, Kojima’s microlensing star is in the direction opposite the center, in the constellation Taurus, and it is the closest microlensing discovery at just 1,600 light years. The star field is much sparser than in the direction of the Milky Way’s center and the microlensing star with the exoplanet is much brighter than other microlensing stars due to its proximity.
Contributing columnist Nick Strobel is director of the William M. Thomas Planetarium at Bakersfield College and author of the award-winning website AstronomyNotes.com.