IYA Live Telescope Today: NGC 6281

Article written: 17 Jun , 2009
Updated: 24 Dec , 2015
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Did you get a chance to watch the IYA Live Telescope today? This time we went hunting galactic open star clusters and we found a beauty! NGC 6281 can be easily spotted in binoculars and small telescopes and we invite you along for the tour. No telescope? No problem. As always, we record a video clip for you so you can enjoy, too!

Your guide star to finding NGC 6281 is Mu Scorpii. About a finger-width east you will find large open galactic star cluster NGC 6281. At magnitude 5.4, you’ll find this sky gem punctuated by a wide pair of 6th magnitude stars. This brightly scattered cluster of three dozen members shows no real nucleus but is easily recognized at low magnifications.

Recent studies have found possible light variations of the member star HD 153919 – identified as an X-ray source. The nebulousity associated with this cluster is also an active HII region and of interest to astronomers wanting to study using Hubble instruments: “We propose a WFPC2 FUV imaging survey of 6 Galactic open clusters with ages ranging from 1 Myr to 300 Myr complemented with NUV/optical imaging of the same fields. No such survey has ever been attempted before in the FUV at the resolution of WFPC2 (indeed, no WFPC2 FUV images of any Galactic open cluster exist in the HST archive) and, since WFPC2 will be retired in SM4 and none of the other HST instruments can do FUV imaging of bright objects, this is the last chance to do such a survey before another UV telescope is launched.” says Dr. Jesus Maiz Apellaniz, “This survey will provide a new perspective on young intermediate age Galactic clusters and a key template for the study of star formation at high redshift, where the intensity peak we observe in the optical/NIR from Earth is located in the FUV in its rest frame. For clusters still associated with an H II region, UV imaging maps the continuum emission of the ionized gas and the radiation scattered by background dust and, combined with optical nebular images, can be used to determine the 3-D structure of the H II region. For all young clusters, FUV+NUV+optical photometry can be used to study the UV excesses of T-Tauri stars. For clusters older than ~40 Myr, the same photometric combination is the easiest method to detect companion white dwarfs which are invisible using only the optical and NIR. WFPC2 is also an excellent instrument to discover close companions around bright stars and improve our knowledge of their multiplicity fraction. Finally, for all clusters, the combination of high-spatial-resolution UV and optical photometry can be used to simultaneously measure the temperature, extinction, extinction law, distance, and existence of companions (resolved and unresolved) and, thus, produce clean HR diagrams with resolved cluster membership and much-reduced systematic uncertainties.”

As always, be sure to enjoy the views from our IYA Live Telescope whenever the skies are clear and dark in Central Victoria by clicking on the link to your right! And have fun… We do!


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