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Sirius Astronomer) Or Editor Don Saito, Donsaito@Yahoo.Com April 2015 Free to members, subscriptions $12 for 12 issues Volume 42, Number 4 NASA’s Dawn spacecraft arrived at dwarf planet Ceres on March 6, revealing the surface of the larg- est unexplored body in the inner Solar System for the first time. These images were taken from 40,000 kilometers (25,000 miles) from Ceres on February 25th. Over the course of the next year we will learn much more about this fascinating and important member of our solar system! (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA) OCA CLUB MEETING STAR PARTIES COMING UP The free and open club meeng will The Black Star Canyon site will open on The next session of the Beginners be held April 10 at 7:30 PM in the Ir‐ April 11. The Anza site will be open on April Class will be held at the Heritage Mu‐ vine Lecture Hall of the Hashinger Sci‐ 18 Members are encouraged to check the seum of Orange County at 3101 West ence Center at Chapman University in website calendar for the latest updates on Harvard Street in Santa Ana on April Orange. This month’s speaker is Dr. star pares and other events. 3. The following class will be held Brendan Bowler of Caltech, who will May 1. discuss Imaging Extrasolar Planets. Please check the website calendar for the outreach events this month! Volunteers are GOTO SIG: TBA NEXT MEETINGS: May 8, June 12 always welcome! Astro‐Imagers SIG: Apr. 14, May 12 Remote Telescopes: TBA You are also reminded to check the web Astrophysics SIG: Apr. 17, May 15 site frequently for updates to the calendar Dark Sky Group: TBA of events and other club news. The Cold Never Bothered Me Anyway By Ethan Siegel For those of us in the northern hemisphere, winter brings long, cold nights, which are often excellent for sky watchers (so long as there's a way to keep warm!) But there's often an add- ed bonus that comes along when conditions are just right: the polar lights, or the Aurora Borealis around the North Pole. Here on our world, a brilliant green light often appears for observers at high northern latitudes, with occasional, dimmer reds and even blues lighting up a clear night. We had always assumed that there was some connection be- tween particles emitted from the Sun and the aurorae, as par- ticularly intense displays were observed around three days after a solar storm occurred in the direction of Earth. Presuma- bly, particles originating from the Sun—ionized electrons and atomic nuclei like protons and alpha particles—make up the vast majority of the solar wind and get funneled by the Earth's magnetic field into a circle around its magnetic poles. They're energetic enough to knock electrons off atoms and molecules at various layers in the upper atmosphere—particles like mo- lecular nitrogen, oxygen and atomic hydrogen. And when the Auroral overlays from the IMAGE spacecraft. Image credit: electrons fall back either onto the atoms or to lower energy NASA Earth Observatory (Goddard Space Flight Center) / levels, they emit light of varying but particular wavelengths— Blue Marble team. oxygen producing the most common green signature, with less common states of oxygen and hydrogen producing red and the occasional blue from nitrogen. But it wasn't until the 2000s that this picture was directly confirmed! NASA's Imager for Magnetopause-to-Aurora Global Ex- ploration (IMAGE) satellite (which ceased operations in December 2005) was able to find out how the magnetosphere responded to solar wind changes, how the plasmas were energized, transported and (in some cases) lost, and many more properties of our magnetosphere. Planets without significant magnetic fields such as Venus and Mars have much smaller, weaker aurorae than we do, and gas giant planets like Saturn have aurorae that primarily shine in the ultraviolet rather than the visible. Nevertheless, the aurorae are a spectacular sight in the evening, particularly for observers in Alaska, Canada and the Scandinavian countries. But when a solar storm comes our way, keep your eyes towards the north at night; the views will be well worth braving the cold! 2 Western Amateur Astronomers Board Meeting Notes by Tim Hogle, WAA Vice President and OCA Representative Once again I would like to report on the activities of the WAA over the last year or so. We had a very productive board meeting on February 7, this time at the Chabot Space and Science Center and Observatory overlooking Oakland and the SF Bay Area. As you will recall, WAA is an umbrella organization whose members are astronomy clubs. It exists for the main purpose of collaboration between member clubs, promoting amateur astronomy, providing awards to individuals for outstanding contribution to the hobby, and hosting or sponsoring the occasional astronomy conference. Eight member clubs were represented at this meeting, including one, Tri-Valley Stargazers (based in Stockton), which has not been active in WAA for many years. We welcome them back. The other clubs, OCA, Los Angeles Astronomical Society, Mt. Diablo Astro- nomical Society and Mt. Diablo Observatory Association, China Peak Astronomical Society, East Bay Astronomical Society, and Chabot Telescope Makers’ Workshop are regulars at this winter meeting. WAA’s most noteworthy regular action at the winter meetings is selection of a recipient for the highly prestigious G. Bruce Blair award, given to a living individual who has made outstanding contributions to amateur astronomy. This year’s award is to be present- ed to Timothy J. Thompson, a retired JPL scientist and president emeritus of LAAS who is being so honored, not only for his four dec- ades of service to LAAS, but for initiation of the docent training program at Mt. Wilson Observatory, leading public outreach there and at Griffith Observatory for many years, as a prolific speaker for astronomy clubs, civic groups, and private functions, both as an ama- teur astronomer and JPL space scientist. As in the last several years, the award will be presented at the Riverside Telescope Makers conference on Memorial Day weekend. The Blair medal itself is quite an involved production effort, which has been done personally by former WAA president Jack Borde. This task, which involves deep chemical etching on a bronze plate using an AutoCad digitized rendering of the original artwork, cut- ting out the medal itself from the plate, lathe turning, edge knurling, engraving with the recipient’s name and finally being gold plated and presented in a hand-crafted wood display case. This task has now been turned over to the Telescope Makers’ Workshop, which has a combination of professional contacts and in-house expertise for all but production of the case. Any woodworkers out there in- terested in donating some time to this last task? Let me know. Two new issues of our New Pacific Stargazer newsletter were issued during this last year. The goal of quarterly issues was not possi- ble, but the semiannual publication has worked well. The Fall 2014 and all other issues can be found from links at the WAA’s web site, http://www.waa.av.org.. We are still looking for material for publication in future issues and are happy to accept articles of as- tronomical interest from individual club members. Contact me (see back page of the Sirius Astronomer) or editor Don Saito, [email protected]. Republication from other sources, such as this one, is okay as well, and will reach a more geographically wide audience. Speaking of which, the SA could really benefit from additional material from OCA members. This august publication is rou- tinely dominated by only a few repeating authors, and would be of greatly enhanced benefit to members with the addition of material from the rest of you. Surely in a club of nearly 800 members there are a few thoughts, personal projects, ideas, insights or reports from astronomically-related trips that could be offered from this audience. Give it some thought and send something in. But I digress. Another continuing effort within WAA is to get a new, updated web page on line. I can’t offer excuses why this has taken so long (at least two years in the works), but I can say we have universal agreement on getting this launched as soon as possi- ble, hopefully before RTMC. WAA will have an information booth at RTMC again this year, probably near the snack bar. Stop by and say hello. For more info about WAA, log on to the web site. 3 AstroSpace Update April 2015 Gathered by Don Lynn from NASA and other sources Solar System visitor – Astronomers have measured the motion of a nearby star and found that it passed through the Oort Cloud of comets that surrounds our Solar System just 70,000 years ago. The star, known as Scholz’s Star, is now 20 light-years away, but at closest approach it was 0.8 light-years. The star is a small dim red dwarf star, so was only about magnitude 11 when nearest. The star has a binary companion, which is a brown dwarf that is even dimmer. There seems to be no evidence that the close passage disturbed the Oort Cloud enough to cause a noticeable increase in comets. Unusual exoplanet – Astronomers have discovered an unusual planet in Kepler (planet finding space telescope) data, which has an elongated orbit. This causes its temperature to change dramatically during each orbit. Its year is 52 Earth days, and during this time the temperature ranges from 900-1800°F (500-1000°C). The planet, dubbed Kepler-432b, is one of the densest and most massive planets known.
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