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Selected links to asteroid, comet, and meteor news   -   April 2007

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Updated: 23 April 2007 (updated)

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[ March 2007 News | News Archive ]
23
April
2007
Monday
  • "April 20, 2007 Fireball," Cloudbait Observatory 23 April - Quote: "The velocity profile is consistent with a stony body approximately 60 cm in diameter... The combination of acoustics, low entry angle, relatively low speed, and multiple fragmentations at low altitude make it likely that meteorites were produced." - Note: This page has been updated with a flight path map and additional images and videos.
     KEYWORDS: 2007 April 20 Colorado event
  • "Meteorites Less Common Than Meteor Showers," 22-23 April
     KEYWORDS: Lyrids
Minor object science papers
  • "Correlation of macroscopic instability and Lyapunov times in the general three-body problem" by Seppo Mikkola & Kiyotaka Tanikawa, abstract & PDF at arXiv.org 23 April - Quote: "We conducted extensive numerical experiments of equal mass three-body systems until they became disrupted. The system lifetimes, as a bound triple, and the Lyapunov times show a correlation similar to what has been earlier obtained for small bodies in the Solar System."
  • "On the stratified dust distribution of the GG Tau circumbinary ring" by C. Pinte, L. Fouchet & 3 others, abstract & PDF at arXiv.org 23 April
     KEYWORDS: circumstellar disks

22
April
2007
Sunday
  • "Tekapo eyed as park in the sky," Stuff.co.nz 22 April - Quote: "The University of Canterbury and other members of the South Island scientific community have begun work promoting the Mount John University Observatory and the broader Tekapo region as a unique [UNESCO] world heritage park in the night sky."
     KEYWORDS: dark skies
  • "Easton noting meteorite anniversary," The Connecticut Post 21 April - Quote: "Dec. 14 will mark the 200th anniversary of when it blazed out of the northern sky in the pre-dawn hours... It is called the 'Weston Meteorite,' because Easton was a part of Weston at the time."
     KEYWORDS: 1807 Dec. 14 Connecticut event
  • "Planet or not, Pluto celebrated in Streator," Bloomington Pantagraph 21 April - Quote: "Planet Pluto Expo will be May 18-19, featuring lectures, exhibits, an ice cream social and a park concert. Clyde Tombaugh was born here in 1906."
     KEYWORDS: IAU planet definition

21
April
2007
Saturday

20
April
2007
Friday
Minor object science papers
  • "3D Radiative Hydrodynamics for Disk Stability Simulations: A Proposed Testing Standard and New Results" by Aaron C. Boley, Richard H. Durisen & 2 others, abstract & PDF at arXiv.org 20 April
  • "An Inner Hole in the Disk around TW Hydrae Resolved in 7 Millimeter Dust Emission" by A.M. Hughes, D.J. Wilner & 4 hours, abstract & PDF at arXiv.org 20 April
     KEYWORDS: circumstellar disks

19
April
2007
Thursday
  • "Or maybe it was space junk: fiery ball presents puzzle," The Sault Star (Sault Ste. Marie, Ontario) 19 April - Quote: "In fact, Dave Gough isn't quite certain exactly what he saw streak through the sky above the Churchill Plaza around 11 a.m. Thursday morning."
     KEYWORDS: 2007 April 19 Ontario event
  • "Asteroid Jiggles Like a Jar of Mixed Nuts," Space.com 19 April - Quote: "[Researchers] suggest the regolith’s patchy distribution is the result of shaking, which causes the finest and lightest materials to accumulate in dips on the asteroid’s surface, where the local gravity is lowest."
     KEYWORDS: 25413 Itokawa (1998 SF36), MUSES-C Hayabusa
  • "Navigating the Stellar Minefield," Science Now 19 April     KEYWORDS: circumstellar disks
  • "When Worlds Really Did Collide," PSRD 18 April
    • "Celestial Fender-Bender Left Asteroid to Cool without Insulation," Univ. of Massachusetts 18 April - Quote: "Roughly 60 meteorites retrieved from around the world have the chemical makeup of the IVA irons, suggesting that they were all part of one metallic asteroid that broke up about 450 million years ago and then fell to earth in pieces."
    • "A new origin for iron meteorites discovered," Univ. of Hawaii at Manoa 18 April - Quote: "Iron meteorites come from the first generation of bodies that formed less than one million years after the solar system was created, and the chondrites formed over the next few million years. Our work therefore shows that planetary embryos 1000 km across formed in less than one million years and that debris from these bodies survived in the form of meteorites and asteroids"
        KEYWORDS: cosmochemistry
Minor object science papers
  • "A survey of debris trails from short-period comets" by William T. Reach, Michael S. Kelley & Mark V. Sykes, abstract & PDF at arXiv.org 19 April - Quote: "There are now 30 Jupiter-family comets with known debris trails, of which 22 are reported in this paper for the first time."
  • "Survival of the mm-cm size grain population observed in protoplanetary disks" by F. Brauer, C.P. Dullemond, & 4 others, abstract & PDF at arXiv.org 19 April
  • "c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe I], and H_2 gas-phase lines" by Fred Lahuis, Ewine F. van Dishoeck, & 4 others, abstract & PDF at arXiv.org 19 April
  • "Imaging the Ionized Disk of the High-Mass Protostar Orion-I" by M. J. Reid, K. M. Menten & 2 others, abstract & PDF at arXiv.org 19 April
     KEYWORDS: circumstellar disks

18
April
2007
Wednesday
  • "UK scientists sift superfine stardust," Royal Astronomical Soc. 18 April - Quote: "The interstellar dust particles collected by Stardust are so tiny that they pose huge analytical challenges."
     KEYWORDS: cosmochemistry
  • "Shields for the starship Enterprise - A Reality?" Royal Astronomical Soc. 18 April - Quote: "[A] team of scientists at the Rutherford Appleton Laboratory are set to construct an experimental magnetic shield that would protect explorers in their journeys between the planets."
     KEYWORDS: manned asteroid missions
  • "Earth's 'Other Moon'," Sky & Telescope 17 April - Quote: "Last September, when a tiny asteroid drifted into Earth’s vicinity, our planet’s gravity captured it. The meter-size object, designated 6R10DB9, is now making its third wide swing around Earth... [It] makes its final and closest pass in June."
          Notes: 6R10DB9 is the Catalina Sky Survey's own discovery designation for this object, which usually would only be used on the MPC's NEO Confirmation Page until an IAU designation was applied, if the object was classified as a minor object. It was "Added Sept. 14.75 UT" to the NEOCP and subsequently removed with the explanation that it "was not a minor planet." The collected astrometry was then published in MPC Distant Artificial Satellites Observation Circular DASO 68 of 17 Sept. and further observations have been published in later circulars, including DASO 97 with astrometry from the 10-meter Southern Africa Large Telescope during 15-18 March.
          JPL Horizons news on March 23rd noted that "6R10DB9 is currently ambiguous, but leaning toward natural," while also noting that there is another object of a somewhat similar nature under recent observation -- "6Q0B44E is thought to be man-made." There is more about that on Bill Gray's "'Pseudo-MPEC' for 6Q0B44E of March 7th, where he says he is "reasonably confident that it is indeed a piece of space hardware."     KEYWORDS: Earth's busy neighborhood

17
April
2007
Tuesday
  • SpaceWeather.com for today [also April 18th] has news about 2007 HA, a not-so-small asteroid just discovered that passed Earth today at about 6.5 lunar distances at 0952 UTC, and also tells where to find Comet Encke, now in view with binoculars at sunset.
     KEYWORDS: 2P/Encke
  • "Meteorite Traces Deep In The Ocean," Russia InfoCentre 17 April - Summary: A crater-like structure 12 km. wide named "Sakhalinka" has been found by Russian scientists 5,900 meters under the Pacific. The scientists think it may have been formed "during the Cretaceous period [when the] ocean level was about 2 km lower than its current level," and was caused by an object on the order of 500 meters in diameter.
     KEYWORDS: Earth impact history
  • "Astronomer, professor searches for new planets," The Appalachian of Appalachian State Univ. 17 April - Quote: "Using the Spizter telescope’s infrared technology, we found many debris discs (an example in our solar system is the Asteroid Belt) around sun-like stars."
     KEYWORDS: circumstellar disks
  • "Dying Sun-like stars leave whirlpools in their wake," Royal Astronomical Soc. 17 April - Quote: "Dying stars eject both gas and dust into space. The dust will coalesce into planets around later generations of stars. The gas contains carbon... The whirlpools in space can play an important role in mixing these essential ingredients into the interstellar gas from which further stars and planets will form." - Note: See also IPHAS and Imperial College's page on circumstellar matter.
     KEYWORDS: cosmochemistry, T Tauri stars
  • "Revised light ordinance back to supervisors," Nevada Appeal 17 April - Quote: "Carson City is seeking a change that would ensure people would be able to look up and see stars on cloudless nights. "     KEYWORDS: dark skies
  • "Meteorite smugglers anger scientists," BBC 16 April
     KEYWORDS: Mauritania
Minor object science papers
  • "Thermal inertia of near-Earth asteroids and implications for the magnitude of the Yarkovsky effect" by Marco Delbo, Aldo Dell'oro & 3 others, abstract & PDF at arXiv.org 16 April
  • "Gaseous Inner Disks" by Joan R. Najita, John S. Carr & 2 others, abstract & PDF at arXiv.org 16 April
     KEYWORDS: circumstellar disks

16
April
2007
Monday
  • "A Bright Naked-Eye Asteroid Occultation," Sky & Telescope 15 April AstroAlert - Quote: "Please watch 4.2-magnitude Iota Cancri blink, and time its occultation by asteroid 411 Xanthe, in s.w. Georgia and n.e. Florida at 8:56 p.m. EDT Tuesday evening, April 17th, to help [IOTA] measure the size and shape of the asteroid, estimated to be 76 kilometers in diameter."
     KEYWORDS: stellar occultations
  • "GRaND instrument primed for voyage," Los Alamos Monitor 14 April - Quote: "[The] Gamma Ray and Neutron Detector (GRaND), one of three science instruments Dawn carries in its payload ... will map the surface of each asteroid for ratios of rock-forming elements and the telltale hydrogen atoms that indicate ice or water. Another goal is to try to pin down Vesta's tantalizing relationship to a class of meteorites known as HEDs ... and to try to determine if any meteorites come from Ceres."
     KEYWORDS: 1 Ceres, 4 Vesta, Dawn asteroid mission
Minor object science papers
  • "Demographics of Transition Objects" by Joan R. Najita, Stephen E. Strom & James Muzerolle et al., abstract & PDF at arXiv.org 16 April - Quote: "The unusual properties of transition objects (young stars with an optically thin inner disc surrounded by an optically thick outer disc) suggest that significant disc evolution has occurred in these systems. We explore the nature of these systems by examining their demographics ... compared to those of accreting T Tauri stars of comparable age."
  • "Warm HCN, C2H2, and CO in the disk of GV Tau" by E.L. Gibb, K.A. Van Brunt & 2 others, abstract & PDF at arXiv.org 16 April - Quote: "We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau."
     KEYWORDS: circumstellar disks, cosmochemistry

13
April
2007
Friday
  • "Early risers catch a 'lucky' look," - Maui News 12 April - Quote: "A brightly glowing object that streaked across the sky above Maui was reported by a few people up early enough Wednesday morning to witness the phenomenon." - Note: From the descriptions and accompanying photos, this was likely a jet contrail. High-flying jet aircraft and their contrails can be spectacularly lit at sunrise or sunset, but a key difference between them and meteor trails is that meteors do not take "one to two minutes" to make their flights, as described in this instance.
     KEYWORDS: 2007 April 12 Hawaii event
  • "Japan Eyes Expansive Space Exploration Agenda," Space.com 12 April - Quote: "JAXA’s road map in space exploration also includes ... a Hayabusa 2 asteroid sample return in 2011."
     KEYWORDS: asteroid missions
  • "A Teacher Who Ignites Minds," Great Neck Record 6 April - Quote: "Whether [Julian Kane] is penning poems about protozoa, or fired up about protecting precious water resources, or exposing the 'bone-headedness' of bureaucrats or theorizing about his hypothesis of a distant, undiscovered planet, his lively discourse makes science come alive and accessible to all his students." - Note: The bit about the undiscovered, KBO-clearing planet is explained in an opinion piece at the same publication dated April 13th, posted on the 12th.
     KEYWORDS: circumstellar disks
  • "Utah Park Earns 'Dark Sky' Status," Sky & Telescope 10 April - Quote: "Given its reputation for pristine skies, you might be surprised to find out that the International Dark-Sky Association (IDA) has challenged the staff at Natural Bridges to do better... [The resulting] effort has led the IDA to recognize Natural Bridges National Monument as the world's first International Dark-Sky Park."
     KEYWORDS: dark skies
Minor object science papers
  • "The orbit, mass, size, albedo, and density of (65489) Ceto/Phorcys: A tidally-evolved binary Centaur" by W.M. Grundy, J.A. Stansberry & 7 others, abstract & PDF at arXiv.org 13 April - Quote: "This density contrasts with lower densities recently measured with the same technique for three other comparably-sized outer Solar System binaries ... and is closer to the density of the saturnian irregular satellite Phoebe."
  • "Light Curves of Dwarf Plutonian Planets and other Large Kuiper Belt Objects: Their Rotations, Phase Functions and Absolute Magnitudes" by Scott S. Sheppard, abstract & PDF at arXiv.org 13 April - Quote: "I report new light curves and determine the rotations and phase functions of several large Kuiper Belt objects, including the dwarf planet Eris (2003 UB313)... It appears the surface properties of the largest dwarf planets in the Kuiper Belt may be different than the smaller Kuiper Belt objects."
  • "Spectral Analysis of the Chandra Comet Survey" by D. Bodewits, D.J. Christian & 8 others, abstract & PDF at arXiv.org 13 April - Quote: "Our analysis showed that [X-ray] spectral differences can be ascribed to different solar wind states, as such identifying comets interacting with (I) fast, cold wind, (II), slow, warm wind and (III) disturbed, fast, hot winds associated with interplanetary coronal mass ejections. We furthermore predict the existence of a fourth spectral class, associated with the cool, fast high latitude wind."
  • "Interaction of Supernova Ejecta with Nearby Protoplanetary Disks" by N. Ouellette, S.J. Desch & J.J. Hester, abstract & PDF at arXiv.org 13 April - Quote: "Previous models of Solar System formation considered a supernova shock that triggered the collapse of the Sun's nascent molecular cloud. We advocate an alternative hypothesis, that the Solar System's protoplanetary disk had already formed when a very close (< 1 pc) supernova injected radioactive material directly into the disk."
     KEYWORDS: circumstellar disks, cosmochemistry

12
April
2007
Thursday
  • "Japan has hopes for wounded asteroid mission," AP at the Intl. Herald Tribune 11 April
     KEYWORDS: 25413 Itokawa (1998 SF36), MUSES-C Hayabusa
  • "Dawn Arrives in Florida - A Little After Dawn," NASA/JPL 10 April - Quote: "Dawn only has two more trips to make. One will be in mid-June when it makes the 15-mile journey from the processing facility to the launch pad. The second will be when Dawn rises to begin its eight-year, 3.2-billion-mile odyssey into the heart of the asteroid belt."
     KEYWORDS: 1 Ceres, 4 Vesta
Minor object science papers
  • "Ground-Based Direct Detection of Exoplanets with the Gemini Planet Imager (GPI)" by James R. Graham, Bruce Macintosh & 10 others, abstract & PDF at arXiv.org 12 April - Quote: "[GPI] is an "extreme" adaptive optics system being designed and built for the Gemini Observatory... GPI's primary science goal is the direct detection and characterization of young, Jovian-mass exoplanets... GPI will also discover faint debris disks [and] explore icy moons and minor planets in the solar system."
  • "SkyMapper and the Southern Sky Survey - a resource for the southern sky" by S.C. Keller, B.P. Schmidt & M.S Bessell, abstract & PDF at arXiv.org 12 April - Quote: "The SkyMapper telescope is a 1.3m telescope currently under construction by the Australian National University ... at Siding Spring Observatory... The SkyMapper imager will utilise the recently developed [StarGrasp] controllers developed for the Pan-STARRS project."
     KEYWORDS: circumstellar disks

11
April
2007
Wednesday
Minor object science paper
  • "The dynamics of Jupiter and Saturn in the gaseous proto-planetary disk" by Morbidelli Alessandro & Aurelien Crida, abstract & PDF at arXiv.org 11 April - Quote: "Initially both planets migrate towards the Sun, and Saturn's migration tends to be faster. As a consequence, they eventually end up locked in a mean motion resonance. If this happens in the 2:3 resonance, the resonant motion is particularly stable, and the gaps opened by the planets in the disk may overlap... If the gap overlap is substantial, planet migration may even be stopped or reversed... We discuss the compatibility of our results ... to explain the current orbital architecture of the giant planets and the origin of the Late Heavy Bombardment of the Moon."
     KEYWORDS: circumstellar disks, impact theory

10
April
2007
Tuesday
  • "Review: Fly Me to the Moon," book review at The Space Review 9 April - Quote: "[Edward] Belbruno notes that while Hohmann transfer orbits are easy to compute and have been used for all sorts of spacecraft over the years [there is an alternative that doesn't] require as much propellant to get spacecraft to a particular destination... The latter part of the book explains some future applications [such as] manipulating the orbits of comets."
     KEYWORDS: interplanetary super highway
  • "Rebel with a Cause: The Optimistic Scientist," TCS Daily 9 April - Freeman Dyson quote: "I tell young people that the new technologies of computing, telecommunication, optical detection and microchemistry actually empower the amateur to do things that only professionals could do before. Amateurs and small companies will have a growing role in the future of science. This will compensate for the increasing bureaucratization of the big organizations."
     KEYWORDS: Benny Peiser, CCNet
  • "Astronomer wants to limit light pollution," Daily Sentinel 9 April - Quote: "Though the Texas Constitution does not allow counties to regulate light pollution... [in] 1978, the Legislature passed a bill that created a 57-mile buffer around the McDonald Observatory [and in 2001 it] allowed Texas counties to impose light restrictions [for] the five miles surrounding the SFA Observatory and the George Observatory."
     KEYWORDS: dark skies

9
April
2007
Monday
  • "University will not shrink observatory at Coonabarabran," Australian ABC 9 April - Quote: "The Australian National University has sought to allay fears it plans to close part of the Siding Springs Observatory at Coonabarabran, in northern New South Wales."
     KEYWORDS: Australia
Minor object science papers
  • "Wide Field Surveys and Astronomical Discovery Space" by A.Lawrence, abstract & PDF at arXiv.org 9 April - Quote: " I review the status of science with wide field surveys... summarise major recent wide field surveys - 2MASS, SDSS, 2dfGRS, and UKIDSS [and] look briefly at upcoming projects in the optical-IR survey arena - VISTA, PanSTARRS, WISE, and LSST."
  • "Predicting the frequencies of diverse exo-planetary systems" by J.S. Greaves, D.A. Fischer & 3 others, abstract & PDF at arXiv.org 9 April - Quote: "Extrasolar planetary systems range from hot Jupiters out to icy comet belts more distant than Pluto. We explain this diversity in a model where the mass of solids in the primordial circumstellar disk dictates the outcome... The differing dependences on metallicity for forming massive planets and low-mass cometary bodies are also explained."

8
April
2007
Sunday
  • "Caltech's Planet Hunter Mike Brown Wins Annual Feynman Prize for Teaching," Caltech at SpaceRef.com 8 April - Quote: "The graduate course [Formation and Evolution of Planetary Systems] is probably the most intuitively taught physics class on campus. For me, if you can't talk the equation out, you don't really understand it, so everything in the class is aimed at making the physics accessible to geologists who don't need to get heavily into the theoretical aspects, but really need to understand certain equations to do their work."
     KEYWORDS: education, dwarf planets, KBOs
  • "Asteroid attack! Scientists say it's coming -- and try to stop it," Orlando Sentinel 7 April
     KEYWORDS: asteroid surveys, planetary defense

6
April
2007
Friday
  • "Interview with a comet-hunter," Nepali Times 6 April
     KEYWORDS: Alan Hale
  • "NASA chief set to cut projects," Orlando Sentinel 6 April - Quote: "The agency also aims to cut programs that encourage student experiments, cancel the construction of a new education complex and reduce funding for an upcoming asteroid-research mission."
    • "NASA Plan Cuts Moon Lander, Boosts Mars Rover," Aviation Week 6 April - Quote: "The U.S./German Stratospheric Observatory for Infrared Astronomy (SOFIA) nabbed a $47 million increase, pending a 'comprehensive independent science review' later this year."
        KEYWORDS: airborne astronomy, NASA budget
  • "Stardust's Data May Be Contaminated, Report Says," Popular Mechanics 5 April - Quote: "Donald Brownlee, principle investigator on the Stardust Project and professor at the University of Washington, believes [precautions] were so robust that contamination from rocket fuel isn't likely."
     KEYWORDS: 81P/Wild 2, cosmochemistry
  • "Deep Impact Extended Mission Could Probe Deeper Into Solar System Origin," NASA/GSFC 5 April - Quote: "If approved, as Deep Impact passes by Earth on December 31, 2007, it will use our planet's gravity to direct itself to comet Boethin."
     KEYWORDS: 9P/Tempel 1, 85P/Boethin
Minor object science paper
  • "Interplanetary Transfer of Photosynthesis: An Experimental Demonstration of A Selective Dispersal Filter in Planetary Island Biogeography" by Charles S. Cockell, Andre Brack & 13 others, abstract at SpaceRef.com 6 April & PDF at Astrobiology journal - Quote: "We launched a cryptoendolithic habitat, made of a gneissic impactite inoculated with Chroococcidiopsis sp., into Earth orbit. After orbiting the Earth for 16 days, the rock entered the Earth's atmosphere and was recovered in Kazakhstan... The experiment advances our understanding of how island biogeography works on the interplanetary scale."
     KEYWORDS: artificial meteorites, panspermia

5
April
2007
Thursday
  • "Developer threatens to parcel out land," Arizona Star 5 April - Quote: "It also would create light pollution that might interfere with work at Whipple Observatory atop nearby Mount Hopkins, observatory officials said. They've called for [letting] the county buy the land for open space."
     KEYWORDS: dark skies
  • "Searching for the Grandest Asteroid Tour," JPL 5 April - Quote: "The problem posed by JPL's Outer Planets Mission Analysis Group for the second competition was to design a flight path for visiting four asteroids-- one from each [asteroid] group -- in the shortest amount of flight time and with the least amount of propellant... The winning trajectory was found by a team from the Polytechnic of Turin, Italy ... followed by trajectories from a Russian team (the Moscow Aviation Institute and the Khrunichev State Research and Production Space Center), and a team from the European Space Agency's Advanced Concepts Team."
     KEYWORDS: asteroid mining
  • "Rare Saint-Exupery watercolor to be shown," The Japan Times 5 April - Quote: "[The] work depicts an asteroid inhabited by a businessman that the little prince stops at before coming to the Earth... Of the 47 Saint-Exupery paintings that illustrate the book, only a handful have been found."
     KEYWORDS: B612
  • "Hayabusa to start return trip to Earth in mid April," SpaceRef.com 4 April from the JAXA Hayabusa MUSES-C news page - Quote: "The operation of the Hayabusa is still undergoing difficulties, but JAXA will do its utmost to make the explorer return home in June 2010."
     KEYWORDS: 25413 Itokawa (1998 SF36)
  • "Metal fragment that hit home not a meteorite," Bloomington Pantagraph 4 April - Quote: "[The] metal object appears to have been ejected from a wood grinder from Twin City Wood Recycling."
     KEYWORDS: 2007 March 5 Illinois event, meteor-wrong
  • "Near-Earth Object Survey and Definition Analysis of Alternatives: Report to Congress," NASA JPL 12 March updated 4 April
     KEYWORDS: asteroid surveys, planetary defense
Minor object science papers
  • "Title: Millimeter imaging of HD 163296: probing the disk structure and kinematics" by A. Isella, L. Testi & 4 others, abstract & PDF at arXiv.org 5 April - Quote: "We argue that these results support the idea that the disk of HD 163296 is strongly evolved. In particular, we suggest that there is a strong depletion of dust relative to gas outside 200 AU; this may be due to the inward migration of large bodies that form in the outer disk or to clearing of a large gap in the dust distribution by a low mass companion."
  • "Mass and Temperature of the TWA 7 Debris Disk" by B.C. Matthews, P.G. Kalas & M.C. Wyatt, abstract & PDF at arXiv.org 5 April - Quote: "These data confirm the presence of a cold dust disk around TWA 7, a member of the TW Hydrae Association. Based on the 850 micron flux, we estimate the mass of the disk to be 18 lunar masses (0.2 Earth masses)."
  • "Giant Planet Migration in Viscous Power-Law Discs" by R.G. Edgar, abstract & PDF at arXiv.org 5 April - Quote: "A planet in a circumstellar disc exerts a torque on the disc material at resonances... By Newton’s Third Law, there is an opposite torque on the planet, which causes it to migrate. Planets of mass comparable to Jupiter (the exact threshold depends on the disc conditions) exert torques comparable to the viscous torque in the disc. They can therefore open a gap in the disc. If the gap is perfectly clean, then the planet will act as a 'relay station' between the inner and outer discs."
     KEYWORDS: circumstellar disks

4
April
2007
Wednesday
  • "Rocky Horror," Willamette Week 4 April - Quote: "As if [Rep. John] Lim's tourism guesstimates weren't questionable enough, his resolution [demanding return of the meteorite] with no force of law is also generating a good deal of concern from the Confederated Tribes of Grand Ronde."
     KEYWORDS: Willamette Meteorite
  • "Reach for the stars," Idaho Mountain Express 4 April - Quote: "I came up here in the late-70s. I was just blown away and it got me interested in preserving the night sky here, which led to the dark sky ordinances for Ketchum and Hailey."
     KEYWORDS: dark skies
  • "How did life on Earth originate?" Fraunhofer-Gesellschaft 3 April - Quote: "Rather than developing here, could the first life forms have been catapulted to Earth on a chunk of rock from outer space? Investigations show that microbes are capable of surviving just such a journey."
     KEYWORDS: panspermia
Minor object science papers
  • "Visible spectroscopic and photometric survey of Jupiter Trojans: final results on dynamical families" by S. Fornasier, E. Dotto & 5 others, abstract & PDF at arXiv.org 4 April - Quote: "We present the results of a visible spectroscopic and photometric survey of Jupiter Trojans belonging to different dynamical families carried out at the ESO-NTT telescope... The survey allows us to investigate six families (Aneas, Anchises, Misenus, Phereclos, Sarpedon, Panthoos) in the L5 cloud and four L4 families (Eurybates, Menelaus, 1986 WD and 1986 TS6). The sample that we measured is dominated by D-type asteroids, with the exception of the Eurybates family in the L4 swarm, where there is a dominance of C- and P-type asteroids."
  • "Formation and Collisional Evolution of Kuiper Belt Objects" by Scott J. Kenyon, Benjamin C. Bromley & 2 others, abstract & PDF at arXiv.org 4 April - Quote: "This chapter summarizes analytic theory and numerical calculations for the formation and collisional evolution of KBOs at 20-150 AU. We describe the main predictions of a baseline self-stirring model and show how dynamical perturbations from a stellar flyby or stirring by a giant planet modify the evolution."
  • "Periodic accretion from a circumbinary disk in the young binary UZ Tau E" by Eric L.N. Jensen, Saurav Dhital & 6 others abstract & PDF at arXiv.org 4 April - Quote: "The photometric variations are in good agreement with predictions from simulations of binaries with orbital parameters similar to those of UZ Tau E, suggesting that periodic accretion does occur from circumbinary disks, replenishing the inner disks and possibly extending the timescale over which they might form planets."
  • "Cometary diversity and cometary families" by J. Crovisier, abstract & PDF at arXiv.org 2 April - Quote: "Comets are classified from their orbital characteristics into two separate classes: nearly-isotropic, mainly long-period comets and ecliptic, short-period comets. Members from the former class are coming from the Oort cloud. Those of the latter class were first believed to have migrated from the Kuiper belt where they could have been accreted in situ, but recent orbital evolution simulations showed that they rather come from the trans-Neptunian scattered disc."
     KEYWORDS: circumstellar disks, scattered disk

3
April
2007
Tuesday
  • SpaceWeather.com for April 3rd tells about Comet Machholz "swinging past the sun this week well inside the orbit of Mercury," a passage viewable online via SOHO.
     KEYWORDS: 96P/Machholz
  • "New Manual for Occultation Observers," Sky & Telescope 3 April AstroAlert - Quote: "[IOTA] has just released a new [385-page] book, Chasing the Shadow: The IOTA Occultation Observer's Manual. It's free, online, and ready for downloading... [It's] the only manual you'll need to observe occultations by the Moon, by asteroids, and by other solar-system bodies."
     KEYWORDS: stellar occultations
  • "Appalachian astronomer helps in search for new planets," Appalachian State Univ. 3 April - Quote: "[Richard] Gray was invited to participate in the project because of his NASA-funded Nearby Stars project. Since 2000, Gray and a team of researchers have been collecting data on 3,600 nearby stars that may harbor planets." - Note: For more about the study of extrasolar debris disks, see March 29th news links.     KEYWORDS: circumstellar disks
  • "This Rock Really Rolls Along," Sky & Telescope 2 April - Quote: "Despite a nearly full Moon, backyard astronomers around the world turned their telescopes skyward this past weekend to track down asteroid 2006 VV2."
     KEYWORDS: Earth's busy neighborhood
Minor object science paper
  • "Two new basaltic asteroids in the Outer Main Belt" by R. Duffard & F. Roig, abstract & PDF at arXiv.org 3 April - Quote: "The identification of other basaltic objects in the asteroid belt is mandatory to explain the diversity in the collection of basaltic meteorites. This diversity requires more than one differentiated parent body, a fact that is consistent with the diversity of differentiated parent bodies implied by the iron meteorites... We also demonstrate that the searching for candidate V-type asteroids using a photometric survey, like the Sloan Digital Sky Survey, produces reliable results."
     KEYWORDS:1459 Magnya, 7472 Kumakiri, 10537 1991 RY16, Calar Alto Observatory

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"stacks"
These sites take a similar approach to stacking publicly-available science news links hand-selected by knowledgeable individuals, sometimes with annotation:

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