ALBERT

Description: Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gaudi, B S -- Bennett, D P -- Udalski, A -- Gould, A -- Christie, G W -- Maoz, D -- Dong, S -- McCormick, J -- Szymanski, M K -- Tristram, P J -- Nikolaev, S -- Paczynski, B -- Kubiak, M -- Pietrzynski, G -- Soszynski, I -- Szewczyk, O -- Ulaczyk, K -- Wyrzykowski, L -- OGLE Collaboration -- Depoy, D L -- Han, C -- Kaspi, S -- Lee, C-U -- Mallia, F -- Natusch, T -- Pogge, R W -- Park, B-G -- MuFUN Collaboration -- Abe, F -- Bond, I A -- Botzler, C S -- Fukui, A -- Hearnshaw, J B -- Itow, Y -- Kamiya, K -- Korpela, A V -- Kilmartin, P M -- Lin, W -- Masuda, K -- Matsubara, Y -- Motomura, M -- Muraki, Y -- Nakamura, S -- Okumura, T -- Ohnishi, K -- Rattenbury, N J -- Sako, T -- Saito, To -- Sato, S -- Skuljan, L -- Sullivan, D J -- Sumi, T -- Sweatman, W L -- Yock, P C M -- MOA Collaboration -- Albrow, M D -- Allan, A -- Beaulieu, J-P -- Burgdorf, M J -- Cook, K H -- Coutures, C -- Dominik, M -- Dieters, S -- Fouque, P -- Greenhill, J -- Horne, K -- Steele, I -- Tsapras, Y -- PLANET and RoboNet Collaborations -- Chaboyer, B -- Crocker, A -- Frank, S -- Macintosh, B -- New York, N.Y. -- Science. 2008 Feb 15;319(5865):927-30. doi: 10.1126/science.1151947.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA. gaudi@astronomy.ohio-state.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18276883" target="_blank"〉PubMed〈/a〉

Description: Observations of the gravitational microlensing event MOA 2003-BLG-32/OGLE 2003-BLG-219 are presented, for which the peak magnification was over 500, the highest yet reported. Continuous observations around the peak enabled a sensitive search for planets orbiting the lens star. No planets were detected. Planets 1.3 times heavier than Earth were excluded from more than 50% of the projected annular region from approximately 2.3 to 3.6 astronomical units surrounding the lens star, Uranus-mass planets were excluded from 0.9 to 8.7 astronomical units, and planets 1.3 times heavier than Saturn were excluded from 0.2 to 60 astronomical units. These are the largest regions of sensitivity yet achieved in searches for extrasolar planets orbiting any star.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abe, F -- Bennett, D P -- Bond, I A -- Eguchi, S -- Furuta, Y -- Hearnshaw, J B -- Kamiya, K -- Kilmartin, P M -- Kurata, Y -- Masuda, K -- Matsubara, Y -- Muraki, Y -- Noda, S -- Okajima, K -- Rakich, A -- Rattenbury, N J -- Sako, T -- Sekiguchi, T -- Sullivan, D J -- Sumi, T -- Tristram, P J -- Yanagisawa, T -- Yock, P C M -- Gal-Yam, A -- Lipkin, Y -- Maoz, D -- Ofek, E O -- Udalski, A -- Szewczyk, O -- Zebrun, K -- Soszynski, I -- Szymanski, M K -- Kubiak, M -- Pietrzynski, G -- Wyrzykowski, L -- New York, N.Y. -- Science. 2004 Aug 27;305(5688):1264-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Solar Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-01, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15333833" target="_blank"〉PubMed〈/a〉

Description: Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth's) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet's temperature is much lower, 〈60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gould, A -- Udalski, A -- Shin, I-G -- Porritt, I -- Skowron, J -- Han, C -- Yee, J C -- Kozlowski, S -- Choi, J-Y -- Poleski, R -- Wyrzykowski, L -- Ulaczyk, K -- Pietrukowicz, P -- Mroz, P -- Szymanski, M K -- Kubiak, M -- Soszynski, I -- Pietrzynski, G -- Gaudi, B S -- Christie, G W -- Drummond, J -- McCormick, J -- Natusch, T -- Ngan, H -- Tan, T-G -- Albrow, M -- DePoy, D L -- Hwang, K-H -- Jung, Y K -- Lee, C-U -- Park, H -- Pogge, R W -- Abe, F -- Bennett, D P -- Bond, I A -- Botzler, C S -- Freeman, M -- Fukui, A -- Fukunaga, D -- Itow, Y -- Koshimoto, N -- Larsen, P -- Ling, C H -- Masuda, K -- Matsubara, Y -- Muraki, Y -- Namba, S -- Ohnishi, K -- Philpott, L -- Rattenbury, N J -- Saito, To -- Sullivan, D J -- Sumi, T -- Suzuki, D -- Tristram, P J -- Tsurumi, N -- Wada, K -- Yamai, N -- Yock, P C M -- Yonehara, A -- Shvartzvald, Y -- Maoz, D -- Kaspi, S -- Friedmann, M -- New York, N.Y. -- Science. 2014 Jul 4;345(6192):46-9. doi: 10.1126/science.1251527.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA. ; Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland. ; Turitea Observatory, Palmerston North, New Zealand. ; Department of Physics, Chungbuk National University, Cheongju 371-763, Republic of Korea. cheongho@astroph.chungbuk.ac.kr. ; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. ; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA. Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland. ; Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK. ; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA. Universidad de Concepcion, Departamento de Astronomia, Casilla 160-C, Concepcion, Chile. ; Auckland Observatory, Auckland, New Zealand. ; Possum Observatory, Patutahi, New Zealand. ; Farm Cove Observatory, Centre for Backyard Astrophysics, Pakuranga, Auckland, New Zealand. ; Possum Observatory, Patutahi, New Zealand. Auckland University of Technology, Auckland, New Zealand. ; Perth Exoplanet Survey Telescope, Perth, Australia. ; Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. ; Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843-4242, USA. ; Department of Physics, Chungbuk National University, Cheongju 371-763, Republic of Korea. ; Korea Astronomy and Space Science Institute, Daejeon 305-348, Republic of Korea. ; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan. ; University of Notre Dame, Department of Physics, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670, USA. ; Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland, New Zealand. ; Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand. ; Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232, Japan. ; Department of Earth and Space Science, Osaka University, Osaka 560-0043, Japan. ; Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK. ; Nagano National College of Technology, Nagano 381-8550, Japan. ; Department of Earth, Ocean and Atmospheric Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada. ; Tokyo Metropolitan College of Aeronautics, Tokyo 116-8523, Japan. ; School of Chemical and Physical Sciences, Victoria University, Wellington, New Zealand. ; Mount John University Observatory, Post Office Box 56, Lake Tekapo 8770, New Zealand. ; Department of Physics, Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555, Japan. ; School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24994642" target="_blank"〉PubMed〈/a〉

Description: There are by now ten published detections of fast radio bursts (FRBs) – single bright GHz-band millisecond pulses of unknown origin. Proposed explanations cover a broad range from exotic processes at cosmological distances to atmospheric and terrestrial sources. Loeb, Maoz, and Shvartzvald have previously suggested that FRB sources could be nearby flare stars, and pointed out the presence of a W-UMa-type contact binary within the beam of one out of three FRB fields that they examined. To further test the flare-star hypothesis, we use time-domain optical photometry and spectroscopy, and now find possible flare stars in additional FRB fields, with one to three such cases among all eight FRB fields studied. We evaluate the chance probabilities of these possible associations to be in the range ~0.1 per cent to 9 per cent, depending on the input assumptions. Further, we re-analyse the probability that two FRBs recently discovered three years apart within the same radio beam are unrelated. Contrary to other claims, we conclude with 99 per cent confidence that the two events are from the same repeating source. The different dispersion measures between the two bursts then rule out a cosmological intergalactic-medium origin for the dispersion measure, but are consistent with the flare-star scenario with a varying plasma blanket between bursts. Finally, we review some theoretical objections that have been raised against a local flare-star FRB origin, and show that they are incorrect.

Description: We present a statistical analysis of the first four seasons from a ‘second-generation’ microlensing survey for extrasolar planets, consisting of near-continuous time coverage of 8 deg 2 of the Galactic bulge by the Optical Gravitational Lens Experiment (OGLE), Microlensing Observations in Astrophysics (MOA), and Wise microlensing surveys. During this period, 224 microlensing events were observed by all three groups. Over 12 per cent of the events showed a deviation from single-lens microlensing, and for ~one-third of those the anomaly is likely caused by a planetary companion. For each of the 224 events, we have performed numerical ray-tracing simulations to calculate the detection efficiency of possible companions as a function of companion-to-host mass ratio and separation. Accounting for the detection efficiency, we find that $55^{+34}_{-22}\hbox{ per cent}$ of microlensed stars host a snowline planet. Moreover, we find that Neptune-mass planets are ~10 times more common than Jupiter-mass planets. The companion-to-host mass-ratio distribution shows a deficit at q ~ 10 –2 , separating the distribution into two companion populations, analogous to the stellar-companion and planet populations, seen in radial-velocity surveys around solar-like stars. Our survey, however, which probes mainly lower mass stars, suggests a minimum in the distribution in the super-Jupiter mass range, and a relatively high occurrence of brown-dwarf companions.

Description: We present Hubble Space Telescope ( HST ) imaging observations of the site of the Type-Ia supernova SN2011fe in the nearby galaxy M101, obtained about 1 yr prior to the event, in a narrow band centred on the He ii 4686 Å emission line. In a ‘single-degenerate’ progenitor scenario, the hard photon flux from an accreting white dwarf (WD), burning hydrogen on its surface over ~1 Myr should, in principle, create a He iii Strömgren sphere or shell surrounding the WD. Depending on the WD luminosity, the interstellar density, and the velocity of an outflow from the WD, the He iii region could appear unresolved, extended, or as a ring, with a range of possible surface brightnesses. We find no trace of He ii 4686 Å line emission in the HST data. Using simulations, we set 2 upper limits on the He ii 4686 Å luminosity of L He ii 〈 3.4 x 10 34 erg s –1 for a point source, corresponding to an emission region of radius r  〈 1.8 pc. The upper limit for an extended source is L He ii 〈 1.7 x 10 35  erg s –1 , corresponding to an extended region with r  ~ 11 pc. The largest detectable shell, given an interstellar-medium density of 1 cm –3 , has a radius of ~6 pc. Our results argue against the presence, within the ~10 5  yr prior to the explosion, of a supersoft X-ray source of luminosity L bol 3 x 10 37  erg s –1 , or of a super-Eddington accreting WD that produces an outflowing wind capable of producing cavities with radii of 2–6 pc.

Description: Six cases of fast radio bursts (FRBs) have recently been discovered. The FRBs are bright (~0.1–1 Jy) and brief (~1 ms) pulses of radio emission with dispersion measures (DMs) that exceed Galactic values, and hence FRBs have been interpreted to be at cosmological distances. We propose, instead, that FRBs are rare eruptions of flaring main-sequence stars within ~1 kpc. Rather than associating their excess DM with the intergalactic medium, we relate it to a blanket of coronal plasma around their host star. We have monitored at optical bands the stars within the radio beams of three of the known FRBs. In one field, we find a bright ( V  = 13.6 mag) variable star (0.2 mag peak to trough) with a main-sequence G-type spectrum and a period P  = 7.8 h, likely a W-UMa-type contact binary. Analysis of our data outside of the FRB beams indicates a 5 per cent probability of finding, at random, a variable star of this brightness and amplitude within the FRB beams, but this could still be a chance coincidence. We find no unusual variable stars in the other two FRB fields. Further observations are needed to investigate if similar nearby (800 pc) stars are the sources of FRBs.

Description: We report the discovery of the sixth known eclipsing double white dwarf (WD) system, SDSS J1152+0248, with a 2.3968 ± 0.0003 h orbital period, in data from the Kepler Mission's K2 continuation. Analysing and modelling the K2 data together with ground-based fast photometry, spectroscopy, and radial-velocity measurements, we determine that the primary is a DA-type WD with mass M 1  = 0.47 ± 0.11 M , radius R 1  = 0.0197 ± 0.0035 R , and cooling age t 1  = 52 ± 36 Myr. No lines are detected, to within our sensitivity, from the secondary WD, but it is likely also of type DA. Its central surface brightness, as measured from the secondary eclipse, is 0.31 of the primary's surface brightness. Its mass, radius, and cooling age, respectively, are M 2  = 0.44 ± 0.09 M , $R_2=0.0223^{+0.0064}_{-0.0050}\,\mathrm{R}_{\odot }$ , and t 2  = 230 ± 100 Myr. SDSS J1152+0248 is a near twin of the double-lined eclipsing WD system CSS 41177.

Description: Using a method to discover and classify supernovae (SNe) in galaxy spectra, we find 90 Type Ia SNe (SNe Ia) and 10 Type II SNe among the ~700 000 galaxy spectra in the Sloan Digital Sky Survey Data Release 7 that have star-formation histories (SFHs) derived with the VErsatile SPectral Analysis code ( vespa ). We use the SN Ia sample to measure SN Ia rates per unit stellar mass. We confirm, at the median redshift of the sample, z  = 0.1, the inverse dependence on galaxy mass of the SN Ia rate per unit mass, previously reported by Li et al. for a local sample. We further confirm, following Kistler et al., that this relation can be explained by the combination of galaxy ‘downsizing’ and a power-law delay-time distribution (DTD; the distribution of times that elapse between a hypothetical burst of star formation and the subsequent SN Ia explosions) with an index of –1, inherent to the double-degenerate progenitor scenario. We use the method of Maoz et al. to recover the DTD by comparing the number of SNe Ia hosted by each galaxy in our sample with the vespa -derived SFH of the stellar population within the spectral aperture. In this galaxy sample, which is dominated by old and massive galaxies, we recover a ‘delayed’ component to the DTD of 4.5 ± 0.6 (statistical)${_{-0.5}\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!^{\rm +0.3}}$ (systematic) x 10 – 14 SNe M – 1 yr – 1 for delays in the range 〉2.4 Gyr. The mass-normalized SN Ia rate, averaged over all masses and redshifts in our galaxy sample, is $R_{{\rm Ia,M}}(z=0.1) = 0.10 \pm 0.01\ (\rm statistical) \pm 0.01\ (\rm systematic)\ {\rm SNuM}$ , and the volumetric rate is R Ia, V ( z = 0.1) = 0.247${_{-0.026}\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!^{\rm +0.029}}$  (statistical) ${_{-0.031}\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!^{\rm +0.016}}$  (systematic) x 10 – 4 SNe yr – 1 Mpc – 3 . This rate is consistent with the rates and rate evolution from other recent SN Ia surveys, which together also indicate a ~ t –1 DTD.