© 2017 Phys.org Cataclysmic variables (CVs) are binary star systems comprising of a white dwarf and a normal star companion. They irregularly increase in brightness by a large factor, then drop back down to a quiescent state. Polars are a subclass of cataclysmic variables, distinguished from other CVs by the presence of a very strong magnetic field in their white dwarfs.IGR J19552+0044 was detected in 2006 by the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) space telescope. Subsequent observations of this highly variable X-ray source have shown that it is a magnetic cataclysmic variable. Now, Tovmassian’s team has revealed the results of a new follow-up optical observational campaign, which helped the researchers to obtain further information about this variable object.For their observations, the astronomers employed three telescopes at the National Astronomical Observatory (OAN) in Sierra San Pedro Mártir, Mexico, two Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) at Cerro Tololo Inter-American Observatory (CTIO) in Chile, and one telescope of South African Astronomical Observatory (SAAO) in South Africa. In the study, the authors also included data obtained by the MDM Observatory on Kitt Peak, Arizona as well as the results provided by the Center for Backyard Astrophysics (CBA), a global network of telescopes observing CVs.This comprehensive observational campaign spanning three years (from June 2011 to July 2014) allowed the team to classify the studied X-ray source correctly.”We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this X-ray source correctly,” the paper reads.According to the study, photometric and spectroscopic observations reveal that the white dwarf of IGR J19552+0044 has spin period and binary orbital period of 83.6 and 81.3 minutes, respectively. These discording results indicate that the studied CV is an asynchronous polar. “The system is not an ordinary polar. The photometric period that we identify with the spin period of the magnetic white dwarf is 2.8 percent shorter than the spectroscopic period; we think the latter reflects the orbital period of the system. This is one of the extreme cases of asynchronism,” the researchers wrote in the paper.The study underlines that such rate of asynchronism is among the largest observed in a few similar objects. The scientists are also uncertain about the source of this deviation, however the growing number of found asynchronous polars suggests that such anomaly is not as rare as originally thought. Besides detecting the asynchronism, the authors estimated the magnetic field strength of the white dwarf in this system. They reveal that this value is more likely about 16 MG and not higher than 20 MG. New magnetic cataclysmic variable star discovered Explore further (Phys.org)—An international team of astronomers led by Gagik H. Tovmassian of the National Autonomous University of Mexico (UNAM) has uncovered new details into the nature of a cataclysmic variable known as IGR J19552+0044. New observations reveal that this object is an asynchronous short period polar. The finding was presented October 5 in a paper published online on the arXiv pre-print server. More information: IGR J19552+0044: A new asynchronous short period polar: “Filling the gap between intermediate and ordinary polars”, arXiv:1710.02126 [astro-ph.SR] arxiv.org/abs/1710.02126AbstractBased on XMM—Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar. We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this X-ray source correctly. Extensive multicolor photometric and medium- to high-resolution spectroscopy observations were performed and period search codes were applied to sort out the complex variability of the object. We found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric (83.599+/-0.002m) periods that we ascribe to the white dwarf (WD) spin period and binary orbital period, respectively. This confirms that IGR J19552+0044 is an asynchronous polar. Wavelength-dependent variability and its continuously changing shape point at a cyclotron emission from a magnetic WD with a relatively low magnetic field below 20 MG. The difference between the WD spin period and the binary orbital period proves that IGR J19552+0044 is a polar with the largest known degree of asynchronism (0.97 or 3%). Power spectra multiband photometry of IGR 1955+0044. The solid lines are powers after clean procedure is applied to powers presented as dotted lines. The bluish curves are for the V band, the red are for the I band, and the green are for the WL light curves. Credit: Tovmassian et al., 2017. Citation: Astronomers identify new asynchronous short period polar (2017, October 16) retrieved 18 August 2019 from https://phys.org/news/2017-10-astronomers-asynchronous-short-period-polar.html 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.
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For example, this blog post from our site links to another one of our blog posts on the same site.Image Source: (Screenshot) Optinmonster.com Importantly, you want to add links in a natural way that will be useful and help guide your readers. Make sure your anchor text (the clickable text in a hyperlink) is relevant to the post you’re linking to, use a follow link and include a keyword for even better results. Remember, don’t overdo it by adding too many links to one small paragraph; that can make your content unreadable and irritate users. Related: 6 Advanced Techniques for Link-Building as a Future SEO StrategyOver to you.Building links can take time, but it doesn’t have to be hard. With these tips and just a little bit of dedication and patience, your link-building skills can skyrocket this year. As long as you’re consistent with this task, you’ll be able to watch your website rise to the top of search engine results and receive an influx of traffic. Opinions expressed by Entrepreneur contributors are their own. 5 min read
<< Previous PostNext Post >> “How you doin’?” Sexy koala wins the Internet with super seductive pose QUEENSLAND — What did the koala say to the photographer? “Draw me like one of your French girls, Jack” as it struck a come-hither pose in a tree.The sexy marsupial didn’t really say those words, of course, but the famous line from ‘Titanic’ did serve as the caption of a now-viral photo taken by 27-year-old British photographer Ross Long.Long snapped the pic while at Currumbin Wildlife Sanctuary in Queensland on Australia’s Gold Coast and knew instantly that this koala was special. For one thing, it was super chilled out (“He looked more chilled than a Friday night of Netflix and chill,” Long told the Daily Mail).Secondly, it posed in that tree in a way that would suggest it was “ready for action”, its chest puffed out, its legs draped seductively across a branch, and his eyes staring longingly directly at the camera.Slay, koala, slay!Long, who noted that there were other female koalas nearby, surmised that this was “his way of letting them know that he was indeed ready.”More news: Apply now for AQSC’s agent cruise ratesWhatever the stud was trying to do, we are all for it, along with everyone else on social media! @alowe842 wrote on Instagram: “did you girls see this, hubba hubba”, while @telmotaylor90s said that it was “Changing the animal kingdom game.” @lissa_babyyy called it “one sexy guy”, @cindyarroba wrote “He’s sexy and he knows it”, and @odetta_odile jokingly alluded to a possible x-rated version of the same pic, writing “That’s the original version”Now that Stud-Koala has gained a legion of new fans, it’s only a matter of time until he comes out with a calendar of sexy poses!