Astronomers discover a giant planet spinning up its star

first_img Astronomers discover seven new giant exoplanets Unbinned instrumental r band light curve of HATS-18 folded with the period P = 0.8378434 days resulting from the global fit. The solid line shows the best-fit transit model. In the lower panel we zoom–in on the transit; the dark filled points here show the light curve binned in phase using a bin-size of 0.002. Credit: arXiv:1606.00848 [astro-ph.EP] Explore further More information: HATS-18 b: An Extreme Short—Period Massive Transiting Planet Spinning Up Its Star, arXiv:1606.00848 [astro-ph.EP] arxiv.org/abs/1606.00848AbstractWe report the discovery by the HATSouth network of HATS-18 b: a 1.980 +/- 0.077 Mj, 1.337 +0.102 -0.049 Rj planet in a 0.8378 day orbit, around a solar analog star (mass 1.037 +/- 0.047 Msun, and radius 1.020 +0.057 -0.031 Rsun) with V=14.067 +/- 0.040 mag. The high planet mass, combined with its short orbital period, implies strong tidal coupling between the planetary orbit and the star. In fact, given its inferred age, HATS-18 shows evidence of significant tidal spin up, which together with WASP-19 (a very similar system) allows us to constrain the tidal quality factor for Sun-like stars to be in the range 6.5 <= lg(Q*/k_2) <= 7 even after allowing for extremely pessimistic model uncertainties. In addition, the HATS-18 system is among the best systems (and often the best system) for testing a multitude of star—planet interactions, be they gravitational, magnetic or radiative, as well as planet formation and migration theories. In order to find exoplanets orbiting HATS-18, the team used the Hungarian-made Automated Telescope Network-South (HATSouth) to obtain over 10,000 images of this sun-like star. This observation campaign was carried out between April 2011 and July 2013. The astronomers also conducted a series of follow-up spectroscopic observations in 2015, utilizing the 2.3 m telescope at the Siding Spring Observatory in Australia and the 2.2 m MPG/ESO telescope at the European Southern Observatory (ESO) in Chile.The radial velocity signals collected by the researchers allowed them to distinguish a sinusoidal variation in phase with the transit ephemeris, confirming the presence of a massive planet around HATS-18. According to the study, the newly detected exoplanet has a radius of about 1.34 Jupiter radii and is two times more massive than our solar system's biggest planet. The orbital period of HATS-18b equals 0.84 days. This exoworld is a typical example of a "hot Jupiter"—a gas giant planet with characteristics similar to the solar system's biggest planet. Hot Jupiters have high surface temperature as they orbit their host stars very closely.What intrigues the scientists about the newly found planetary system is that the planet appears to be tidally spinning up the star."The high planet mass, combined with its short orbital period, implies strong tidal coupling between the planetary orbit and the star. In fact, given its inferred age, HATS-18 shows evidence of significant tidal spin up," the researchers wrote in the paper.Penev and his colleagues believe that this system could be one of the best laboratories for testing theories of star–planet interactions and planet formation. They noted that modeling this "spin-up" effect for this system alone would bring promising results regarding the tidal dissipation efficiency."Such modeling may begin to disentangle some of the very poorly understood physics behind tidal dissipation by measuring its dependence on various system properties. (…) Extremely short-period planets like HATS-18b provide a fantastic laboratory to test a range of interactions between the planet and the star, and hence, expanding this sample is extremely valuable for the study of extrasolar planets," the paper reads.The researchers propose performing similar studies on a larger number of exoplanet systems, especially on all planets with extremely short orbital periods like HATS-18b. These future analyses could provide new insights on the dependence of tidal dissipation on planetary system parameters. In conclusion, the team endorses more systematic studies of other giant exoworlds similar to HATS-18b."Clearly, a more systematic effort to analyze all suitable exoplanet systems and properly account for the stellar angular momentum loss uncertainties is bound to yield very meaningful constraints on the stellar tidal dissipation, as well how it changes with various system properties," the team wrote. (Phys.org)—A giant "hot Jupiter" exoplanet has recently been detected by an international team of astronomers led by Kaloyan Penev of Princeton University. The newly found alien world, designated HATS-18b, is an interesting case of a planet tidally spinning up its parent star. Moreover, this planetary system could be a great laboratory for researchers when it comes to testing theories of planet–star interactions. The new findings were presented in a paper published online on June 2 on arXiv.org. © 2016 Phys.org Citation: Astronomers discover a giant planet spinning up its star (2016, June 7) retrieved 18 August 2019 from https://phys.org/news/2016-06-astronomers-giant-planet-star.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.last_img read more

Man held for sexually abusing street shedog

first_imgKolkata: In a bizarre incident, a person was arrested on charges of sexually abusing a street she-dog inside his residence at Bidhanpally in Patipukur under Lake Town police station area.The person Kamlesh Mahato has been arrested by the police on the basis of a complaint lodged by an NGO that works for animal welfare. According to police sources, one Prantik Chatterjee, a resident of Narayan Roy Road in Barisha under Thakurpukur police station area, who runs an NGO, lodged a written complaint at Lake Town police station regarding this unnatural sexual lust. Also Read – Sowing activities on track with ample rain in S Bengal districtsChatterjee along with some of his friends were passing through Patipukur area at around 9 pm on Sunday night when they found the person luring a street she-dog to his residence. They sniffed something unusual in his act and followed him inside the house.They were surprised to find that he was trying to fulfill his unnatural lust through the animal.He had put a piece of cloth on its mouth to stop her from barking. Kamlesh noticed that Chatterjee and his friends were keeping an eye on him and he somehow managed to flee the spot Also Read – Son-in-law arrested in connection with Garden Reach murder incidentChatterjee and his friends reported the matter to the Lake Town police station, who made arrangements to take the animal to Belgachia Veterinary Hospital.The animal was treated there and the medical test confirmed that she was sexually abused.The police has initiated a case under section 377 (whoever voluntarily has carnal inter­course against the order of nature with any man, woman or animal) and arrested Kamlesh in this collection.The arrested person, who is a daily labour, is married and has kids. They are presently at their hometown in a neighbouring state. The incident reminded of a similar incident that had taken place at Bargram under Shyampur police station in Howrah, where a cow was killed by a person after sexually assaulting it.The person Sujal Maity had stole the cow from one of his neighbour’s farm.He was arrested by the local police after the locals caught him and beat him up for such an act.It may be mentioned that Maity had tried to steal a cow six months back before the incident but his attempt was averted by the locals.last_img read more

The Right Way to Monetize Your Free App

first_img Attend this free webinar and learn how you can maximize efficiency while getting the most critical things done right. In the app business, it typically takes exceptionally high awareness and brand name recognition to actually get users to buy the app.  However, with a free mobile app, companies have to generate revenue through advertisements, which often manifest in the form of disruptive third party pop-ups or prolonged pre-roll, creating major deterrents for regular usage.If more companies learn how to appropriately monetize their free apps, they will retain more users and increase app usage. Proper integration of advertisements into the content of the app is key to avoid unwanted friction for users — a feat that is absolutely possible but rarely witnessed.To profit from a free app while retaining users can be done. Companies simply need to be more strategic with advertising options.Here are a few tips:Related: 3 Strategies for Winning In the Hyper-Competitive Market for AppsDon’t have ads that are disruptive. Once a user has gone through the trouble of downloading and opening the app, half the battle has been won. Now an app has the opportunity to win over a user with unique, interactive content.However, some mobile advertisements are so intrusive that users never have the opportunity to appreciate the content. For instance the pre-roll video advertisements automatically play and force the user to watch before they can access app content. These are entirely too long for the average consumer’s attention span and typically serve as just another opportunity for the user to reconsider his or her interest level in the app. Pop-up ads, while on the screen for a markedly shorter period of time, are equally disruptive to the user experience. They are often difficult to exit out of and can frequently result in the user accidentally tapping on the ad and unwillingly being redirected out of the app altogether.  Further, the accidental tapping of a pop-up ad also creates false data and can skew advertising metrics.Integrate ads into the content.To avoid having advertisements deter regular usage, ads should actually be relevant to the user and integrated into the existing content on the app. Native advertising should be a part of your strategy.For instance, if I am using an app to organize my travel itineraries and tickets, I may not be interested in pop-up ads for a new dating site. It’s possible that the ad could catch my attention, but it tracks far more logically to populate a travel app with travel-related offerings. In addition, if you can integrate the advertisements into part of the app content, the placements will be far less obtrusive to users who are not interested and may become far more compelling for those who are. The advertisements then become part of the app experience rather than fight against it.Related: 7 Musts to Maximize Your Company’s Mobile StrategyEnhance the experience.Advertisements aren’t always a necessary evil. By utilizing placements more as sponsored content within the app, ads can actually enhance the user experience.Returning to the travel app example, the user is far more likely to click on advertisements for hotels or cab services while navigating through the app. Not only does this provide valuable metrics for advertisers but could also create convenience for the user.Other ways in which advertisements can benefit the user include giving the consumer access to exclusive deals or other real-world incentives, or having advertisers sponsor interactive quizzes or polls. Geo-targeting advertisements within an app can help increase engagement by displaying ads that are local to the user. Additionally, deploying remarketing tactics within your app can leverage ad content that the user has already shown interest in, further personalizing the experience.In an over-saturated app marketplace, a user most likely won’t think twice about deleting a free app with intrusive advertising and moving on to a competitor.  In order to be successful, companies must simultaneously keep both advertisers and users happy. It becomes a precarious balancing act in which you cannot have one without the other. But for organizations that take the initiative to properly monetize a free app, the line that must be toed becomes much more navigable. Related: 3 Tips to Help You Stand Out From the App Pack  March 31, 2015 4 min read Free Webinar | Sept 5: Tips and Tools for Making Progress Toward Important Goals Opinions expressed by Entrepreneur contributors are their own. Register Now »last_img read more