Last time, we set ourselves up with a nice place to cool off and had a drink or two. And as the evening rolls up, we can lay back with our drinks, dipping our feet in the distant APM 08279+5255 quasar, and watch the universe set. Maybe we can catch a shooting star or two. Of course, I am referring to an actual star shooting across the sky!
Possibly the most studied star that is hurling around the Milky Way is Mira A (Latin for wonderful). Clocking in at around 291,000 miles per hour, Mira A is part of a binary star system (Mira A and Mira B) with a 500-year orbit around its partner, which can be seen in the constellation Cetus from Earth. Mira is also a swollen red giant. A red giant is a small-to-average mass star that is nearing the end of its life. Inside our Sun, a prime example of a small-to-average mass star, nuclear reactions happen constantly as hydrogen fuses into helium. But when the hydrogen runs out in one of these stars (as will happen in the Sun in billions of years), the star will begin to contract, causing immense pressure and energy. This causes the star to expand greatly into a red giant. If Mira A were to magically swap places with the Sun, it would engulf everything out to Mars. What makes Mira A so spectacular, though, is its tail. We’ve actually known about Mira for about 400 years, but it wasn’t until recently that we’ve exposed what is really going on. As Mira travels through space with her companion, she leaves behind mass as she burns fuel. This mass gives off light in ultraviolet wavelengths, and it wasn’t until 2007 when she was viewed with the Galaxy Evolution Explorer (GALEX) that we saw her tail. Hold on to your hats, because it’s a head turner.
Mira had had it. Twinkle, twinkle “LITTLE” star?
Animation of Mira A
“In 1890 T Pyxidis had appeared, brightened, and disappeared. When I first came to Harvard they were still telling how it was found again during a routine survey of plates taken in 1919, and how Miss Leavitt exclaimed: ‘That star hasn’t been seen for almost thirty years!’ – the first recurrent nova to be discovered.”
Henrietta Swan Leavitt in the above quote is well known for discovering the period luminosity relationship of Cepheid type variable stars, which has since become an essential rung of the cosmic distance ladder. Cecilia Payne-Gaposchkin may be less widely known, but her contributions are arguably even more important than those of Leavitt’s (try typing “the most brilliant Ph.D. thesis ever written in astronomy” in to your favorite search engine). Years after her thesis work, Payne-Gaposchkin turned her attention to novae, and thanks to brilliant scientists like her, we know a lot about these explosions. Yet there is still much about novae that we don’t understand, and most nova researchers would agree that T Pyxidis (or T Pyx for short) is the most puzzling of them all, recurrent or otherwise.
This year, however, had a particularly special treat for everyone. On Monday, June 3rd, and Tuesday, June 4th, anyone with the gusto and interest could come to the meeting and attend special talks and events for public and amateur astronomers. To celebrate this, the Indiana Astronomical Society held a star party on June 3rd to get everyone ready for the exciting news unleashed in the following days. Now for the meat and potatoes…
Protostars in Messier 78, as seen by multiple observatories
The side-by-side images above depict protostars found in Messier 78, a reflection nebula found within the constellation Orion (but not the Orion Nebula, which is Messier 42). These are some of the youngest stars that astronomers have ever seen – some of them are still embedded deeply in a gaseous envelope, which would suggest that they’re under 25,000 years old. That may seem like a long time compared to our human lives… but for stars that can live for millions or billions of years, it’s still stellar infancy. These images accompanied this press release from the Herschel space observatory, and represent observations from Herschel as well as ground-based telescopes. Though they can be difficult to detect, researchers are hoping to document more young stars in various stages of life – from before birth through infancy – to learn more about the early development of stars.
NASA often looks at “young” astronomical objects, to learn more about the formation and evolution of the Universe. Here’s a selection of some beautiful and interesting cosmic baby pictures… Read more »
Stars and planets form in the dark, inside vast, cold clouds of gas and dust. The James Webb Space Telescope’s large mirror and infrared sensitivity will let astronomers peer inside dusty knots where the youngest stars and planets are forming.
The Webb telescope project has developed a bookmark and an activity that you can try at home, with an after school club, or in the classroom to learn more about the life cycles of stars – from birth in a dusty nebula, through developmental changes, death, and then rebirth.
This informal education activity, where colored pony beads are strung on the bookmark, each representing a phase of the star’s life, can be used with kids ranging from late elementary school to middle school. The activity might be young for high schoolers, but you could go more in depth with the science for this age group.
Fomalhaut + Fomalhaut b; courtesy of NASA, ESA, UC Berkeley, NASA GSFC, Lawrence Livermore National Laboratory, and NASA JPL-Caltech)
For a lot of people, exoplanets are some of the most exciting discoveries in current astronomy. The first exoplanets were detected in 1992 orbiting the pulsar PSR B1257+12, all three of which were confirmed in 2007. In 1995, 51 Pegasi became the first main sequence star to have an exoplanet detected around it. In the years since, interest in exoplanets increased as they became easier to discover and there are now seventy-four NASA-confirmed planets outside our solar system, and thousands more are under close watch to see if they’ll make the cut. But long before we knew for sure they were there, even centuries before the excitement within the field today, astronomers wondered if there were any “other earths” out there – and a lot of them were confident that there were! As it turns out they were right, but a lot of what people hear about exoplanets (or exosolar planets, or extrasolar planets, pick your flavor) doesn’t come from scientific sources, which can breed some interesting discrepancies between science-fiction and science-reality. Read more »
We posted once about NuSTAR, a new X-ray telescope. It was due to be launched in March, but that launch date is now scheduled for June. Below is a great new image of NuSTAR in the nose cone of the Pegasus rocket it will be launched on.
Using NASA’s Galaxy Evolution Explorer, a space-based observatory, and the Pan-STARRS1 telescope on the summit of Haleakala in Hawaii, astronomers have gathered the most direct evidence yet of a supermassive black hole shredding a star that wandered too close.
Credit: NASA, S. Gezari (The Johns Hopkins University), and J. Guillochon (University of California, Santa Cruz)
“When the star is ripped apart by the gravitational forces of the black hole, some part of the star’s remains falls into the black hole while the rest is ejected at high speeds,” said project lead Suvi Gezari of the Johns Hopkins University. “We are seeing the glow from the stellar gas falling into the black hole over time. We’re also witnessing the spectral signature of the ejected gas, which we find to be mostly helium. It is like we are gathering evidence from a crime scene. Because there is very little hydrogen and mostly helium in the gas, we detect from the carnage that the slaughtered star had to have been the helium-rich core of a stripped star.”
The above image and this video are computer simulations:
The video shows a star being shredded by the gravity of a massive black hole. As the video caption says, “Some of the stellar debris falls into the black hole and some of it is ejected into space at high speeds. The areas in white are regions of highest density, with progressively redder colors corresponding to lower-density regions. The blue dot pinpoints the black hole’s location. The elapsed time corresponds to the amount of time it takes for a Sun-like star to be ripped apart by a black hole a million times more massive than the Sun.”
Credit: NASA, ESA, D. Lennon and E. Sabbi (ESA/STScI), J. Anderson, S. E. de Mink, R. van der Marel, T. Sohn, and N. Walborn (STScI), N. Bastian (Excellence Cluster, Munich), L. Bedin (INAF, Padua), E. Bressert (ESO), P. Crowther (University of Sheffield), A. de Koter (University of Amsterdam), C. Evans (UKATC/STFC, Edinburgh), A. Herrero (IAC, Tenerife), N. Langer (AifA, Bonn), I. Platais (JHU), and H. Sana (University of Amsterdam)
Star-forming region 30 Doradus is colloquially known as the Tarantula Nebula (creepy!), but this new image released with data from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys makes it look more like a rich underwater scene. Located within our galaxy’s close neighbor, the Large Magellanic Cloud, it is one of the best stellar nurseries for astronomers to observe prolific star birth and learn more about how young stars form and grow. This image combines dozens of observations from Hubble, showing off star clusters at varying ages. The false color in this image represents the hot gas within the regions – red signifies hydrogen gas and blue represents oxygen. What a tangled web these stars weave!
This beautiful, infrared image shows a new view of the Eagle nebula captured by the European Herschel Space Observatory. In 1995, Hubble famously captured a visble-light image of the “Pillars of Creation,” a region of star-formation. That image is below – in the above image, that region is shown within the circle.
Credit: NASA, Jeff Hester, and Paul Scowen (Arizona State University)
Infrared light is needed to see into the opaque clouds of dust and gas within which stars form. You can read more about what astronomers are learning from this new view of the nebula in the NASA feature.
This is a doozy of a round-up, thanks to the American Astronomical Society meeting mid-month! Maggie already blogged about some of the interesting exoplanet news that came out at the meeting. Here, we’ll cover some of the other big astrophysics releases at AAS! But first… a gorgeous image from the European Southern Observatory.
This image of the Omega Nebula (M17 or NGC 6618) was captured by the ESO’s ground-based Very Large Telescope (VLT). The nebula contains glowing hydrogen gas and filaments of dust, the very materials needed to create the the blue-white baby stars forming in this very active stellar nursery. You can read more about the nebula and this image in the ESO press release.