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Astronomer, outreach coordinator and producer of the monthly news segment of the Jodcast.
Rigel
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- August 23, 2010
- 11:04 AM
- 45 views
In the news this month: pulsar irregularities
After massive stars like explode, the object left behind is thought to be either a or a black hole, depending on the final mass of the progenitor star. are neutron stars that have strong magnetic fields and behave somewhat like cosmic lighthouses, projecting beams of radio emission into space as they spin. Studying the pulses of radiation as the beams sweep past the Earth can provide valuable information on the physics of these extreme objects, allowing astronomers to probe physics under cond........ Read more »
Lyne, A., Hobbs, G., Kramer, M., Stairs, I., & Stappers, B. (2010) Switched Magnetospheric Regulation of Pulsar Spin-Down. Science, 329(5990), 408-412. DOI: 10.1126/science.1186683
- July 2, 2010
- 05:45 AM
- 134 views
In the news this month: a drop in eta Carinae's stellar wind
are the violent explosions of massive stars, so bright that the events can be seen in distant galaxies. But not all apparent explosions are genuine supernovae. Some fall into the category of , the sudden increase in brightness of a star without the terminal explosion. One such impostor event was the , a star which is amongst the most massive known in the Milky Way. Located 7,500 light years away in the constellation of Carina, the star is five million times more luminous than the Sun and an est........ Read more »
Mehner, A., Davidson, K., Humphreys, R., Martin, J., Ishibashi, K., Ferland, G., & Walborn, N. (2010) A SEA CHANGE IN ETA CARINAE . The Astrophysical Journal, 717(1). DOI: 10.1088/2041-8205/717/1/L22
- June 7, 2010
- 04:20 AM
- 143 views
In the news this month... Hubble spots a planet-eating star
Most of the discovered so far are in the class known as "", large gas giants orbiting close to their parent stars, since many of the search techniques used are most sensitive to this type of planet. Usually these planets are located close enough to their parent star that they orbit in just a few days, but a team that is orbiting so close to its parent star that it is actually being disrupted.The planet, known as WASP-12b, is located in the constellation of Auriga and was discovered in the , or........ Read more »
Fossati, L., Haswell, C., Froning, C., Hebb, L., Holmes, S., Kolb, U., Helling, C., Carter, A., Wheatley, P., Cameron, A.... (2010) METALS IN THE EXOSPHERE OF THE HIGHLY IRRADIATED PLANET WASP-12b. The Astrophysical Journal, 714(2). DOI: 10.1088/2041-8205/714/2/L222
- June 7, 2010
- 04:00 AM
- 134 views
In the news this month... runaway star in 30 Doradus
One of the most spectacular examples of a star formation region in the nearby universe is , also known as the , located in the Large Magellanic Cloud. This region is a giant stellar nursery, similar to the , but much larger, containing many clusters of recently formed young, hot stars. Some of the young stars in the nebula are many tens of times more massive than the Sun, making them some of the most massive stars known. New observations, on May 5th, show that one particular star is travelling ........ Read more »
Evans, C., Walborn, N., Crowther, P., Hénault-Brunet, V., Massa, D., Taylor, W., Howarth, I., Sana, H., Lennon, D., & van Loon, J. (2010) A MASSIVE RUNAWAY STAR FROM 30 DORADUS. The Astrophysical Journal, 715(2). DOI: 10.1088/2041-8205/715/2/L74
- June 7, 2010
- 03:45 AM
- 128 views
In the news this month... a possible new class of supernova
Most supernovae are classified as one of two different types of explosion: single massive short-lived stars that explode when their cores run out of fuel at the end of their lives and undergo gravitational collapse, and old evolved white dwarfs in binary systems which accrete hydrogen from a companion star before exploding catastrophically.; are generally seen only in regions of ongoing star formation since, by stellar standards, their supergiant progenitors do not live for very long. In contra........ Read more »
Perets, H., Gal-Yam, A., Mazzali, P., Arnett, D., Kagan, D., Filippenko, A., Li, W., Arcavi, I., Cenko, S., Fox, D.... (2010) A faint type of supernova from a white dwarf with a helium-rich companion. Nature, 465(7296), 322-325. DOI: 10.1038/nature09056
Kawabata, K., Maeda, K., Nomoto, K., Taubenberger, S., Tanaka, M., Deng, J., Pian, E., Hattori, T., & Itagaki, K. (2010) A massive star origin for an unusual helium-rich supernova in an elliptical galaxy. Nature, 465(7296), 326-328. DOI: 10.1038/nature09055
- May 31, 2010
- 02:09 PM
- 135 views
In the news this month... volcanoes on Venus
Closer to home, the planet Venus shows large amounts of evidence of volcanic activity. Despite being shrouded under a thick layer of cloud, spacecraft have been able to map the surface of our nearest neighbour using radar, leading to the realisation that much of the planet's surface is comparatively young, suggesting that at some point in the recent past the planet underwent a complete resurfacing. However the question remains whether Venus is currently a geologically active planet.... Read more »
Smrekar, S., Stofan, E., Mueller, N., Treiman, A., Elkins-Tanton, L., Helbert, J., Piccioni, G., & Drossart, P. (2010) Recent Hotspot Volcanism on Venus from VIRTIS Emissivity Data. Science, 328(5978), 605-608. DOI: 10.1126/science.1186785
- May 31, 2010
- 09:49 AM
- 158 views
In the news this month... the strange atmosphere of GJ 436b
Most known extrasolar planets are massive gas giants orbiting close to their parent stars. If one of these planets happens to pass directly between us and its parent star during its orbit, then sensitive spectroscopy can be used to determine the chemical make-up of its atmosphere. Models of such atmospheres predict which gases should be present and in what relative abundances, based on physical conditions such as the temperature. Recent infra red observations carried out with the have provided ........ Read more »
Stevenson, K., Harrington, J., Nymeyer, S., Madhusudhan, N., Seager, S., Bowman, W., Hardy, R., Deming, D., Rauscher, E., & Lust, N. (2010) Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b. Nature, 464(7292), 1161-1164. DOI: 10.1038/nature09013
- May 31, 2010
- 08:19 AM
- 127 views
In the news this month... the nature of the eclipsing binary system epsilon Aurigae
Many stars vary in brightness, sometimes due to changes within the star itself such as novae or Cepheid variables, others because of external factors. One is , an F-type supergiant in the constellation of Auriga, located at an estimated distance of 625 parsecs (2,100 light years). Since its variable nature was discovered in the 1820s, the star has been seen to fade in brightness every 27.1 years. During these eighteen-month-long eclipses, the brightness of the star fades to around 50 per cent o........ Read more »
Kloppenborg, B., Stencel, R., Monnier, J., Schaefer, G., Zhao, M., Baron, F., McAlister, H., ten Brummelaar, T., Che, X., Farrington, C.... (2010) Infrared images of the transiting disk in the ε Aurigae system. Nature, 464(7290), 870-872. DOI: 10.1038/nature08968
- March 4, 2010
- 02:31 AM
- 223 views
In the News this month: emission from methane in the atmosphere of an extrasolar planet
In just fifteen years, have been discovered around stars other than the Sun using a variety of techniques. Even without the ability to directly image these other worlds, some of their properties can be determined. Most extra solar planets found so far are massive orbiting close to their parent stars, since these are the types of planets that the detection methods are most sensitive to. As develop and improve, astronomers are finding out more and more about these other worlds, including the co........ Read more »
Swain, M., Deroo, P., Griffith, C., Tinetti, G., Thatte, A., Vasisht, G., Chen, P., Bouwman, J., Crossfield, I., Angerhausen, D.... (2010) A ground-based near-infrared emission spectrum of the exoplanet HD 189733b. Nature, 463(7281), 637-639. DOI: 10.1038/nature08775
- March 4, 2010
- 01:58 AM
- 223 views
In the News this month: the molecular content of early galaxies
A long-standing question in the study of is whether the process was more efficient in the early universe than it is today. Stars form through the collapse of clouds of cold gas. As the collapse progresses, the of the cloud gets denser and hotter until begins and a star is born. In the local universe, however, cold molecular gas is relatively rare so star formation occurs slowly; the Milky Way forms new stars at a rate of only a few per year. More distant galaxies formed stars at a much higher........ Read more »
Tacconi, L., Genzel, R., Neri, R., Cox, P., Cooper, M., Shapiro, K., Bolatto, A., Bouché, N., Bournaud, F., Burkert, A.... (2010) High molecular gas fractions in normal massive star-forming galaxies in the young Universe. Nature, 463(7282), 781-784. DOI: 10.1038/nature08773
- March 4, 2010
- 01:16 AM
- 282 views
In the News this month: the explosion mechanism behind type Ia supernovae
Supernova explosions are initially by the chemical signatures in their optical spectra. While some are caused by the catastrophic collapse of stars more than eight times as massive as the Sun, others are thought to be caused by , stars like the Sun which have already evolved off the main sequence and shrunk in size. Called Type Ia supernovae, such explosions are thought to have a fixed brightness, allowing them to be used as to measure distances to galaxies and test cosmological models of the ........ Read more »
Gilfanov, M., & Bogdán, A. (2010) An upper limit on the contribution of accreting white dwarfs to the type Ia supernova rate. Nature, 463(7283), 924-925. DOI: 10.1038/nature08685
- February 2, 2010
- 12:02 AM
- 218 views
In the news this month: the coolest brown dwarf yet
An international team, led by astronomers at the University of Hertfordshire have discovered what may be the coolest sub-stellar body ever found outside our own solar system. Using the United Kingdom Infrared Telescope (UKIRT) in Hawaii, the , smaller than other stars but larger than gas giant planets such as Jupiter. The object, known as SDSS1416+13B, is only visible in infra-red light and is in a wide orbit around a somewhat brighter and warmer known as SDSS1416+13A. This discovery is "the fo........ Read more »
Ben Burningham, S. K. Leggett, P. W. Lucas, D. J. Pinfield, R. L. Smart, A. C. Day-Jones, H. R. A. Jones, D. Murray, E. Nickson, M. Tamura.... (2010) The discovery of a very cool binary system. MNRAS. arXiv: 1001.4393v1
- February 1, 2010
- 11:50 PM
- 195 views
In the news this month: coronal loops imaged around another star
Most of our knowledge of the processes and morphology of stellar coronae comes from observing our nearest star, the Sun. Coronal loops are associated with sunspot groups which affect the streams of charged particles leaving the Sun as the solar wind, so an understanding of the processes in these loops has implications for space weather predictions which can impact on satellite operations and the safety of astronauts.Studying the same processes in other stars is difficult due to the distances inv........ Read more »
Peterson, W., Mutel, R., Güdel, M., & Goss, W. (2010) A large coronal loop in the Algol system. Nature, 463(7278), 207-209. DOI: 10.1038/nature08643
- February 1, 2010
- 11:18 PM
- 216 views
In the news this month: Chandra tells tails of extragalactic star formation
Star formation is usually thought of as occurring mainly in the spiral arms of galaxies. In close encounters or collisions between galaxies, the orbits of these stars around the galactic disk can be disrupted, resulting in some stars being thrown out into intergalactic space. But new results from the Chandra X-ray Observatory suggest that, at least in some cases, stars can form outside the normal boundaries of galactic disks.A team led by Ming Sun at the University of Virginia used the orbiting ........ Read more »
Sun, M., Donahue, M., Roediger, E., Nulsen, P., Voit, G., Sarazin, C., Forman, W., & Jones, C. (2010) SPECTACULAR X-RAY TAILS, INTRACLUSTER STAR FORMATION, AND ULXs IN A3627. The Astrophysical Journal, 708(2), 946-964. DOI: 10.1088/0004-637X/708/2/946
- January 27, 2010
- 01:21 PM
- 305 views
Doctor Who and the Silver Spiral
Far across the universe, something big was about to happen. The explosion would outshine an entire galaxy and be visible billions of kilometres away. Its light would travel across the universe for millions of years but, aside from a few astronomers, it would go unnoticed on the Earth.With a grating, wheezing noise, a small blue box flickered into existence."So, where are we?""Have a look..." the Doctor replied, tapping a control, "but... don't step outside."The door of the TARDIS clicked open, a........ Read more »
Paragi, Z., Taylor, G., Kouveliotou, C., Granot, J., Ramirez-Ruiz, E., Bietenholz, M., van der Horst, A., Pidopryhora, Y., van Langevelde, H., Garrett, M.... (2010) A mildly relativistic radio jet from the otherwise normal type Ic supernova 2007gr. Nature, 463(7280), 516-518. DOI: 10.1038/nature08713
Crockett, R., Maund, J., Smartt, S., Mattila, S., Pastorello, A., Smoker, J., Stephens, A., Fynbo, J., Eldridge, J., Danziger, I.... (2008) The Birth Place of the Type Ic Supernova 2007gr. The Astrophysical Journal, 672(2). DOI: 10.1086/527299
Soderberg, A., Chakraborti, S., Pignata, G., Chevalier, R., Chandra, P., Ray, A., Wieringa, M., Copete, A., Chaplin, V., Connaughton, V.... (2010) A relativistic type Ibc supernova without a detected γ-ray burst. Nature, 463(7280), 513-515. DOI: 10.1038/nature08714
- January 3, 2010
- 08:48 PM
- 363 views
In the News this month: first observational evidence of a new type of supernova
Stars the size and mass of our Sun end their lives by first expanding as , then shrinking to . Stars heavier than this however, come to a much more violent end.; For stars with masses between about 10 and 100 times that of the Sun, they continue in the core, until they run out of hydrogen. They then begin to fuse the helium nuclei together to form heavier elements such as carbon, nitrogen and oxygen. This carries on through the elements until iron, at which point the to form either a neutron s........ Read more »
Gal-Yam, A., Mazzali, P., Ofek, E., Nugent, P., Kulkarni, S., Kasliwal, M., Quimby, R., Filippenko, A., Cenko, S., Chornock, R.... (2009) Supernova 2007bi as a pair-instability explosion. Nature, 462(7273), 624-627. DOI: 10.1038/nature08579
- January 3, 2010
- 09:03 AM
- 332 views
In the News this month: the role of magnetic fields in GRBs
are highly energetic explosions which release enormous amounts of energy in just a few seconds. So-called because they were first discovered through their intense gamma-ray emission, these explosions can be seen across the visible universe. The exact nature of the jets which give rise to this emission is however, not certain. Different jet models predict very different properties of the magnetic fields present in the out-flowing material. Some models suggest that weak are present only locally ........ Read more »
Steele, I., Mundell, C., Smith, R., Kobayashi, S., & Guidorzi, C. (2009) Ten per cent polarized optical emission from GRB 090102. Nature, 462(7274), 767-769. DOI: 10.1038/nature08590
- January 3, 2010
- 08:27 AM
- 249 views
In the News this month: stellar canibalism in globular clusters
contain some of the oldest known stars.; Formed billions of years ago in the halos of what eventually become the galaxies we see today, globular clusters are roughly spherical collections of stars bound together by their own gravity. Our own Milky Way contains many such clusters, several of which were catalogued by in the 18th Century.While most of the stars in globular clusters have ages of 12 to 13 billion years, some of them appear to be much younger. Most stars in globular clusters are red........ Read more »
Ferraro, F., Beccari, G., Dalessandro, E., Lanzoni, B., Sills, A., Rood, R., Pecci, F., Karakas, A., Miocchi, P., & Bovinelli, S. (2009) Two distinct sequences of blue straggler stars in the globular cluster M 30. Nature, 462(7276), 1028-1031. DOI: 10.1038/nature08607
Mathieu, R., & Geller, A. (2009) A binary star fraction of 76 per cent and unusual orbit parameters for the blue stragglers of NGC 188. Nature, 462(7276), 1032-1035. DOI: 10.1038/nature08568
- December 2, 2009
- 09:03 AM
- 277 views
In the News this month: spectacular outflows in Orion
The constellation of Orion contains some massive complex regions of star formation, the most obvious of which is the , M42, located in Orion's sword. Through an optical telescope you can see a large glowing cloud of gas illuminated by a cluster of young, hot stars. But behind this cloud, hidden from view, lies another cluster of proto-stars, clumps of gas still collapsing under gravity in the process of forming stars. As ordinary light cannot penetrate through the gas, other parts of the el........ Read more »
L. D. Matthews, L. J. Greenhill, C. Goddi, C. J. Chandler, E. M. L. Humphreys, & M. Kunz. (2010) A Feature Movie of SiO Emission 20-100 AU from the Massive Young Stellar Object Orion Source I. Astrophysical Journal. arXiv: 0911.2473v1
- December 2, 2009
- 08:41 AM
- 297 views
In the News this month: a new way to search for exoplanets
are continuously being refined and are detecting ever smaller planets at greater and greater distances from their parent stars. But a team of astronomers have between planetary systems and lithium abundance that could provide a . Most methods of searching for planetary systems around other stars are best suited to finding large planets orbiting very close to their host stars. But what if there was a way to determine the likelihood of a particular star hosting planets, without actually detectin........ Read more »
Israelian, G., Mena, E., Santos, N., Sousa, S., Mayor, M., Udry, S., Cerdeña, C., Rebolo, R., & Randich, S. (2009) Enhanced lithium depletion in Sun-like stars with orbiting planets. Nature, 462(7270), 189-191. DOI: 10.1038/nature08483
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