Tag Archives: 新419龙凤

31Aug/19

Giant planet and brown dwarf discovered in a close binary system HD

first_imgJ and K band AO imaging of HD 87646 taken at Palomar observatory. Credit: Ma et al., 2016. (Phys.org)—An international team of astronomers reports the discovery of a giant planet and a brown dwarf in a close binary system designated HD 87646. The findings, described in a paper published Aug. 11 on arXiv.org, reveal that HD 87646 is the first close binary system with more than one substellar circum-primary companion known to date. Citation: Giant planet and brown dwarf discovered in a close binary system HD 87646 (2016, August 16) retrieved 18 August 2019 from https://phys.org/news/2016-08-giant-planet-brown-dwarf-binary.html Explore further © 2016 Phys.org More information: Very Low-Mass Stellar and Substellar Companions to Solar-like Stars From MARVELS VI: A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646 , arXiv:1608.03597 [astro-ph.EP] arxiv.org/abs/1608.03597AbstractWe report the detections of a giant planet (MARVELS-7b) and a brown dwarf candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. It is the first close binary system with more than one substellar circum-primary companion discovered to the best of our knowledge. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using ET at Kitt Peak National Observatory, HRS at HET, the “Classic” spectrograph at the Automatic Spectroscopic Telescope at Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period brown dwarf in this binary. HD 87646 is a close binary with a separation of ∼22 AU between the two stars, estimated using the Hipparcos catalogue and our newly acquired AO image from PALAO on the 200-inch Hale Telescope at Palomar. The primary star in the binary, HD 87646A, has Teff = 5770±80K, log(g)=4.1±0.1 and [Fe/H] = −0.17±0.08. The derived minimum masses of the two substellar companions of HD 87646A are 12.4±0.7MJup and 57.0±3.7MJup. The periods are 13.481±0.001 days and 674±4 days and the measured eccentricities are 0.05±0.02 and 0.50±0.02 respectively. Our dynamical simulations show the system is stable if the binary orbit has a large semi-major axis and a low eccentricity, which can be verified with future astrometry observations. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. HD 87646, located around 240 light years away, is a bright G-type star with a fainter K-type stellar companion. The primary star in the system, HD 87646A, is about 12 percent more massive than the sun and has a radius of about 1.55 solar radii. The system has a separation of only 22 AU between the two stars.A team of researchers, led by Bo Ma of the University of Florida, has been observing HD 87646 since 2006 using a set of telescopes. The scientists employed the W.M. Keck Exoplanet Tracker (KeckET), at the Sloan Digital Sky Survey (SDSS) 2.5m telescope, mounted on the Apache Point Observatory in New Mexico to reveal the presence of a new giant planet that received designation HD 87646b. KeckET is a new generation multiple object Doppler instrument, capable of simultaneously observing more than 50 stars.The planetary status of HD 87646b was confirmed thanks to the radial velocity observations conducted by utilizing the Kitt Peak National Observatory (KPNO) in Arizona, the High-Resolution Spectrograph at the Hobby-Eberly Telescope (HET) in Texas, the “Classic” spectrograph at the Automatic Spectroscopic Telescope, mounted on the Fairborn Observatory in Arizona and the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) at SDSS. Moreover, these observations allowed the researchers to detect new even larger companion in the system – a brown dwarf designated HD 87646c.”Our SDSS MARVELS pilot survey and additional observations at the HET, KPNO 2.1m telescope, and Fairborn Observatory confirm the detection of two massive substellar companions in a close binary system HD 87646,” the team wrote in the paper.According to the study, HD 87646b has a minimum mass of about 12.4 Jupiter masses and an orbital period of approximately 13.5 days. HD 87646c is much more massive, having 57 Jupiter masses and much longer orbital period, circling the star every 673 days.The team also conducted dynamical simulations of the system, which allowed them to draw conclusions that HD 87646 is stable if it has a large binary semi-major axis and a relatively low binary eccentricity.However, the question of how this system was formed still baffles the authors of the paper. Given the fact that HD 87646 is the first known system to have two massive substellar objects orbiting a star in a close binary and the masses of the two objects are close to the minimum masses for burning deuterium and hydrogen, these peculiarities raise questions about the system’s formation and evolution.”The large masses of these two substellar objects suggest that they could be formed as stars with their binary hosts: a large molecular cloud collapsed and fragmented into four pieces; the larger two successfully became stars and formed the HD 87646 binary, and the other smaller ones failed to form stars and became the substellar objects in this system. This scenario might be relevant for the binary stars but seems problematic for the two substellar objects on orbits within one AU because it is unclear whether fragmentation on such a small scale can occur,” the paper reads.Other hypothesis offered by the scientists is that the two newly discovered giant objects were formed like giant planet in a protoplanetary disk around HD 87646A. However, they added that such massive disks are rare in close binaries, and further investigation is needed to confirm this explanation. Astronomers discover new substellar companion to the Pleiades member starlast_img read more

31Aug/19

48magnitude quake strikes Bengal

first_imgKolkata: iaAn earthquake measuring 4.8 on the Richter scale struck West Bengal’s Bankura district on Sunday, authorities said. According to Regional Meteorological Centre Kolkata, the earthquake occurred at 10.39 a.m. at a depth of 10 kilometres in Bankura region. Tremors were felt in Purulia, Jhargram and other adjoining areas.last_img

30Aug/19

UK Researcher Who Stopped WannaCry Indicted in US

first_imgAugust 4, 2017 A researcher who played a role in halting the spread of the WannaCry ransomware has been indicted by U.S. authorities for allegedly creating the Kronos malware with another individual.As Motherboard reports, U.K.-based researcher Marcus Hutchins, known online as MalwareTech, was arrested in Las Vegas this week, where he was attending the Black Hat and Defcon security conferences.The indictment, filed on July 11 in Wisconsin District Court, says that “Defendant Marcus Hutchins created the Kronos malware,” alongside another person, whose name has been redacted from the filing. Between July 2014 and July 2015, the two “intentionally cause[d] damage without authorization to 10 or more protected computers,” it says.A spokeswoman for the FBI’s Nevada office referred PCMag to the Department of Justice, which did not immediately respond to a request for comment.Hutchins made headlines in May when he stopped the spread of the WannaCry by accident. He noticed the ransomware “queried an unregistered domain, which I promptly registered.” But WannaCry looks to connect to that unregistered domain. If it can’t connect, “it ransoms the system,” MalwareTech explained. If it connects to the domain, though, “the malware exits” and the system is not compromised. After the registration, WannaCry connected to the domain and was stopped in its tracks.According to the indictment, Hutchins’s alleged co-conspirator posted a video that demonstrated how the Kronos malware worked on July 13, 2014. The person then offered to sell the Kronos banking trojan for $3,000 “on an internet forum.”Hutchins reportedly helped this person update the Kronos malware in February 2015, after which it was advertised for sale on the (now-defunct) AlphaBay dark web forum. In June 2015, it sold for about $20,000 in digital currency, the indictment says.As some have pointed out online, Hutchins requested a Kronos sample on the day the video in question went up.Anyone got a kronos sample?— MalwareTech (@MalwareTechBlog) July 13, 2014Fellow researcher Andrew Mabbitt, who traveled to Las Vegas with Hutchins and several other colleagues, says he refuses to believe the charges. “He spent his career stopping malware, not writing it,” Mabbitt says of Hutchins.Mabbitt says he will be “crowdfunding legal fees soon.” The Electronic Frontier Foundation, which often steps in to assist with cases like this, tweeted that it is “deeply concerned about security researcher Marcus Hutchins’ arrest. We are looking into the matter, and reaching out to Hutchins.” Register Now » This story originally appeared on PCMag Free Webinar | Sept. 9: The Entrepreneur’s Playbook for Going Global Growing a business sometimes requires thinking outside the box. 3 min readlast_img read more

26Aug/19

NSA to release GHIDRA their reverse engineering framework to the public at

first_imgThe National Security Agency (NSA) will be publicly releasing their reverse engineering framework called GHIDRA, for the first time at the RSA Conference (Rivest, Shamir, and Adleman security conference) to be held in March 2019. According to the official announcement on the RSA blog, the framework will be introduced by NSA’s Senior Advisor Robert Joyce. According to NSA, GHIDRA has ‘an interactive GUI capability that enables reverse engineers to leverage an integrated set of features that run on a variety of platforms including Windows, Mac O, and LINUX and supports a variety of processor instruction sets’. This is what we know about GHIDRA so far: In March 2017, WikiLeaks leaked CIA Vault 7 documents which highlighted the various tools utilized by the CIA. The leaked documents included numerous references to a reverse engineering tool called ‘GHIDRA’ that was developed by the NSA at the start of the 2000s. For the past few years GHIDRA has been shared with other US government agencies with cyber teams that look at the inner workings of malware strains or suspicious software. GHIDRA is a ‘disassembler’ that breaks down software into its assembly code so that humans can analyze malware and other suspected malicious software. GHIDRA is built in Java, that runs on Linux, Mac and Windows operating systems and has a graphical user interface. With GHIDRA, developers can analyze the binaries of all major operating systems, including mobile platforms like Android and iOS. NSA is expected to add GHIDRA on NSA’s code repository hosted by Github where the spy agency has released several other open source programs. Some people who are familiar with this tool and have shared opinions on HackerNews, Reddit, and Twitter. They have compared GHIDRA with IDA, another well-known reverse engineering tool. Source: HackerNews Head over to RSA’s official blog to check out the announcement. Alternatively, check out Siliconangle for more insights on this news. Read Next NSA’s EternalBlue leak leads to 459% rise in illicit crypto mining, Cyber Threat Alliance report NSA researchers present security improvements for Zephyr and Fucshia at Linux Security Summit 2018last_img read more

19Aug/19

Fancy some Unicorn poop New map tracks Londons best food finds

first_imgFancy some Unicorn poop? New map tracks London’s best food finds Travelweek Group Tags: Food, London Wednesday, August 8, 2018 LONDON — Ever wanted to try Unicorn poop? You can get some in London with help from a new map featuring the city’s most delicious – and bizarre – food fads.Wren Kitchens, a privately-owned family business that manufactures and sells kitchen products, has released its own interpretation of London’s Tube map that shows commuters and tourists where to go in Zone 1 for culinary treasures.Credit: Wren’s KitchenIf you’ve got a hankering for a macaron ice cream sandwich (who doesn’t?!), go to Charing Cross. There’s something called a Matcha Freakshake on Liverpool street, and a super trendy charcoal brioche burger at Paddington.Always a fan favourite, rainbow bagels can be hunted down in the east end of Zone 1 at Aldgate East, while avocado enthusiasts will surely flip over avocado bubble waffles at Piccadilly Circus.And what about the elusive unicorn poop? Follow the map to Old Street for a bowl full of  this much-talked-about fruity, colourful cereal.More news:  TRAVELSAVERS welcomes Julie Virgilio to the teamPhoto Credit: https://www.wrenkitchens.com/blog/food-tube-ultimate-guide-deliciously-instafamous-summer-city/center_img << Previous PostNext Post >> Posted by Sharelast_img read more