Beautiful Sun April 22, 2010
Posted by sarah in: new astronomy, pics . Add a commentFirst results from NASA’s Solar Dynamics Observatory are in! In dynamic fashion, NASA have released a bunch of movies on YouTube of the satellite’s first observations, as well as great images. Enjoy.
Beautiful sun with the coronal mass ejection of 8 April 2010.
Prominence
Eps Aurigae’s dark secret (interferometry rules!) April 8, 2010
Posted by sarah in: astronomy, new astronomy . 3comments
Since a few weeks some PhD students and postdocs have been organising astro-ph coffee meetings three times a week, where the youngsters in the department can sit together and chat about recent papers. The advantage of having these meetings for only students and postdocs is that we can admit to our utter ignorance about stuff we should really know about – like gamma ray burst light curves or cosmic strings – without fearing the judgment of our supervisors. An additional benefit for me is that I now have a small army of minions scoping out interesting new research for me to blog about here. Ha!
Anyway, this morning we talked about a letter in Nature by Kloppenborg et al, published today, showing some fabulous new observations of the space oddity that is ε Aurigae. This star forms part of a binary system and is unusually eclipsed by its invisible companion every 27 years for a lengthy 18-month period. Astronomers have known about this for almost 200 years, and had hoped that the current eclipse, which began last August, would finally provide some definitive answers. The AAVSO has even enlisted citizen scientists worldwide to gather data for the star’s light curve with its Citizen Sky project, and I spotted today that ε Aurigae also has a twitter feed.
The essence of the paper is shown in the above video. These images look like a clever simulation – but these are actually real images (well, apart from the white lines, obviously). They are resolved images of the stellar disk of ε Aurigae! They were taken last November and December, in the early phases of the eclipse, and they clearly show that something dark is moving in front of the star. I’m an instrumentalist, I’m supposed to know this stuff, what we can and can’t observe, but I really didn’t.
Not a planet, still interesting February 7, 2010
Posted by sarah in: new astronomy, pics . Add a comment
Despite Mike Brown‘s best efforts, Pluto is not dead (yet). These cool new images of the tiny non-planet taken with the Hubble Space Telescope show that it is by no means a boring lump of icy rock. When comparing these images, taken in 2002-2003, to a previous set dating back to 1994, scientists noticed some striking changes. This would suggest that Pluto, just like many bodies in the solar system, shows seasonal activity and all kinds of interesting chemistry as it moves along its looong orbit around the Sun.
Image: NASA, ESA, and M. Buie (Southwest Research Institute)
Shape matters in black hole growth January 31, 2010
Posted by sarah in: astronomy, new astronomy . 2comments
Fig. 1 (from Schawinski et al., 2010)
Active galaxies have gone by many names: active galactic nuclei, quasars, QSOs, Seyfert galaxies, radio galaxies. Astronomers used to think these were all distinct types of objects, unified by the observation of large amounts of energy emerging from a compact region at the centre of the galaxy. These days, despite a great variety in observational characteristics, active galaxies’ engines are generally thought to be driven by a single mechanism, the accretion of material onto a supermassive central black hole.
In a paper published to the Arxiv last week, Kevin Schawinski and collaborators have used Galaxy Zoo classifications of local Universe galaxies to show that active elliptical galaxies are markedly different from those with a more disk-like or spiral shapes, adding morphology as an additional factor to consider in our model of active galaxies.
First steps in direct exoplanet spectroscopy January 16, 2010
Posted by sarah in: new astronomy . 2comments
Top: Image of star HR8799 and its exoplanet HR8799c (ESO/M.Janson). Bottom: The spectrum as recorded by the NACO detector, prior to extraction ; the vertical direction is spatial, horizontal is spectral (M. Janson et al, 2010)
Astronomers collaborating from both sides of the Atlantic have obtained the first direct spectrum of an exoplanet. The news here is mainly that they managed to record the spectrum and separate it reliably from that of the host star. Their short letter in ApJ, posted to astro-ph yesterday, doesn’t delve deeply into the implications of what they found but focuses more on the way they obtained, processed and analysed their data to separate the planet’s signature from that of the star.
