More planets than stars in our Milky Way!

Artwork: ESO/M. Kornmesser

When you look at the night sky, from your favorite camping spot [dark sky site], its always amazing to see the myriad of stars painting the night sky.

According to a study released in the journal Nature tomorrow, there are actually more planets than stars in the Milky Way, our home galaxy. Come again? - That's right the ratio of planets to stars is thought to be greater than 1.

Most readers would be aware that the Kepler space mission has detected over 1600 exoplanet candidates so far, but over the past 16 years, astronomers have detected more than 700 (other) confirmed exoplanets and have started to probe the spectra and atmospheres of these worlds. While studying the properties of individual exoplanets is undeniably valuable, a much more basic question remains: how commonplace are planets in the Milky Way?

Arnaud Cassan (Institut dʼAstrophysique de Paris), lead author of the Nature paper, explains: "We have searched for evidence for exoplanets in six years of microlensing observations. Remarkably, these data show that planets are more common than stars in our galaxy. We also found that lighter planets, such as super-Earths or cool Neptunes, must be more common than heavier ones."


There are three methods for detecting exoplanets: 1)A spectroscopic radial velocity measurement 2)Direct observation of a transit where the planet moves in front of the parent star and 3)Microlensing.

Illustration: WASP 8b transits in a retrograde orbit - ESO/L. Calçada

According to the European Southern Observatory: "Microlensing is a very powerful tool, with the potential to detect exoplanets that could never be found any other way. But a very rare chance alignment of a background and lensing star is required for a microlensing event to be seen at all. And, to spot a planet during an event, an additional chance alignment of the planet’s orbit is also needed".


Illustration: Microlensing lightcurve of EROS-BLG-2000-5 - ESO

So these events are more difficult to detect, but a very valuable detection method.

Jean-Philippe Beaulieu (Institut d'Astrophysique de Paris), leader of the PLANET collaboration [Probing Lensing Anomalies NETwork] adds: "The PLANET collaboration was established to follow up promising microlensing events with a round-the-world network of telescopes located in the southern hemisphere, from Australia and South Africa to Chile. ESO telescopes contributed greatly to these surveys.”

In the six year study the astronomers made three successful detections then combined the information with seven additional detections from earlier work, as well as the huge numbers of non-detections in the six year's worth of data. Non-detections are just as important for the statistical analysis and are much more numerous. The conclusion was that one in six of the stars studied hosts a planet of similar mass to Jupiter, half have Neptune-mass planets and two thirds have super-Earths. The survey was sensitive to planets between 75 million kilometres and 1.5 billion kilometres from their stars. In the Solar System this range would include all the planets from Venus to Saturn and with masses ranging from five times the Earth up to ten times Jupiter.


Artwork: ESO

Combining the results suggests strongly that the average number of planets around a star is greater than one. They are the rule rather than the exception.

This result is consistent with some of the early results already coming out of the Kepler Program where already scientists are finding super earths more common than first thought. One of the core goals of the Kepler program is to determine the number of earth sized planets in our galaxy, so it will be interesting to see, as more data becomes available from Kepler, how these studies compare.

“We used to think that the Earth might be unique in our galaxy. But now it seems that there are literally billions of planets with masses similar to Earth orbiting stars in the Milky Way,” concludes Daniel Kubas, co-lead author of the paper.


Image Credit: La Silla Observatory - ESO/Z. Bardon (www.bardon.cz)

More than half of the data from the PLANET survey used in this study came from the Danish 1.54-metre telescope at ESO's La Silla Observatory.

The year 2012 marks the 50th anniversary of the founding of the European Southern Observatory (ESO). ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory.

So.... when you wish upon a star, you can also wish upon "1.n planets" as well ;-)

The calculation of the number of planets in the Milky Way continues!

Acknowledgements:
This research was presented in a paper, “One or more bound planets per Milky Way star from microlensing observations”, by A. Cassan et al., to appear in the 12 January issue of the journal Nature. The team is composed of A. Cassan (Institut dʼAstrophysique de Paris, France [IAP]; ESO), D. Kubas (IAP), J.-P. Beaulieu (IAP), M. Dominik (University of St Andrews, United Kingdom), K. Horne (University of St Andrews), J. Greenhill (University of Tasmania, Australia), J. Wambsganss (Heidelberg University, Germany), J. Menzies (South African Astronomical Observatory), A. Williams (Perth Observatory, Australia), U. G. Jørgensen (Niels Bohr Institute, Copenhagen, Denmark), A. Udalski (Warsaw University Observatory, Poland), M. D. Albrow (University of Canterbury, New Zealand), D. P. Bennett (University of Notre Dame, Notre Dame, USA), V. Batista (IAP), S. Brillant (ESO), J. A. R. Caldwell (McDonald Observatory, Fort Davis, USA), A. Cole (University of Tasmania), Ch. Coutures (IAP), K. Cook (Lawrence Livermore National Laboratory, USA), S. Dieters (University of Tasmania), D. Dominis Prester (University of Rijeka, Croatia), J. Donatowicz (Technical University of Vienna, Austria), P. Fouqué (Université de Toulouse, France), K. Hill (University of Tasmania), N. Kains (ESO), S. Kane (NASA Exoplanet Science Institute, Caltech, USA), J.-B. Marquette (IAP), K. R. Pollard (University of Canterbury, New Zealand), K. C. Sahu (STScI, Baltimore, USA), C. Vinter (Niels Bohr Institute), D. Warren (University of Tasmania), B. Watson (University of Tasmania), M. Zub (Heidelberg University), T. Sumi (Nagoya University, Japan), M. K. Szymański (Warsaw University Observatory), M. Kubiak (Warsaw University Observatory), R. Poleski (Warsaw University Observatory), I. Soszynski (Warsaw University Observatory), K. Ulaczyk (Warsaw University Observatory), G. Pietrzyński (Warsaw University Observatory), Ł. Wyrzykowski (Warsaw University Observatory).

LoveJOY to the world - Astronomers get their christmas present!

Wow!

I have been following this comet for a couple of weeks now, ever since Dec 2nd, when Terry Lovejoy had his confirmation and it was excitedly announced that the humble astronomer from Australia's Gold Coast had become the first observer to discover a comet from a Space Based telescope and an earth based telescope. I'd love to hang that plaque on my wall!

Comet Lovejoy is one of the largest Kreutz class (Sungrazing) comet detected since the SOHO program began, completed perihelion on December 16th and was not expected to survive its passage around the sun at 1.8 Solar radii.

Oooops....no one told Comet Lovejoy it was supposed to conk out near the sun. It has surprised everyone by surviving the close pass and stunning the SOHO team with a birthday present.

As the saying goes "16 and never been kissed" - December the 2nd was the 16th birthday of the SOHO mission and what better way to celebrate than Lovejoy "kissing" the sun and emerging from the other side. Sungrazing comets are so-called because they pass so close to the sun that they rarely survive the passage. Multiple satellite instruments have picked up the comet exiting from behind the sun with its tail gyrating wildly in the solar wind. Latest Lasco instrument photos now show it moving away, still very bright and a partially visible tail that is still mostly obscured by the pixel bleed from the CCD camera.

Comet Lovejoy has lived up to its expectations as being one of the brightest Kreutz Class (Sungrazing) comets of all time.

These images following the passage through the FOV of the LASCO C3 camera and follows the comet's path for 80 hours at approx one hour per half second.

There are three things you really must look at:
1)How long the dust tail persists on the inbound path before is is blown away by the solar wind
2)How the tail swings around after perihelion displaying a prominent Ion Tail (the straight one) that was barely visible before perihelion
3)How prominent the Coma is after perihelion.

There are a number of astronomers scratching their heads today - but generally Lovejoy has followed the basic rules of comets:
1) No two are the same
2) they are highly unpredictable in terms of brightness

Much will be learnt from this one as the space based telescopes have very high resolution images in a variety of spectra.

In the top right hand corner you can also see some meteors apparently emerging from a radiant, the Geminid show is currently in play, but I am unsure if it is this shower that can be seen.

It a little early yet to claim it as a naked eye comet during the Christmas festive season, we hope so, as the world could use a little more Joy ....or LoveJOY ;-) at the moment.

Merry Christmas!

Thanks to the SOHO Team for making the data available.
"The SOHO/LASCO data used here are produced by a consortium of the Naval Research Laboratory (USA), Max-Planck-Institut fuer Aeronomie (Germany), Laboratoire d'Astronomie (France), and the University of Birmingham (UK). SOHO is a project of international cooperation between ESA and NASA."

Comet Lovejoy's sunny death dive! Strike that - It lives on!

UPDATE: 2011/12/16 11:00 UTC


Oooops....no one told Comet Lovejoy it was supposed to conk out near the sun. It has surprised everyone by surviving the close pass and stunning the SOHO team with their birthday present.

As the saying goes "16 and never been kissed" December the 2nd was the 16th birthday of the SOHO mission and what better way to celebrate than Lovejoy "kissing" the sun and emerging from the other side. Sungrazing comets are so-called because they pass so close to the sun that they rarely survive the passage. Multiple satellite instruments have picked up the comet exiting from behind the sun with its tail gyrating wildly in the solar wind. Latest Lasco instrument photos now show it moving away, still very bright and a partially visible tail that is still mostly obscured by the pixel bleed from the CCD camera.

Comet Lovejoy has lived up to its expectations of being one of the brightest Kreutz Class (Sungrazing) comets of all time.

Blazing at mag -3 and out of view for all "earthbound" observers, it is expected to cease to exist sometime in the next 12-18 hours as it approaches within 1.8 Solar radii.




This spectacular sequence from the LASCO C3 instrument on the SOHO observatory records the final death plunge. Note the horizontal artifact is due to the brightness of the coma which overloads the well count of the CCD camera causing pixel bleed.

In the highly unlikely event that the comet does make it round the sun it will be even more news worthy!

"The SOHO/LASCO data used here are produced by a consortium of the Naval Research Laboratory (USA), Max-Planck-Institut fuer Aeronomie (Germany), Laboratoire d'Astronomie (France), and the University of Birmingham (UK). SOHO is a project of international cooperation between ESA and NASA."

UPDATE: Lovejoy appears to have survived its passage, scientists noting with interest the presence of an Ion Tail in a addition to the dust tail, this has apparently not been seen before in a Kreutz Class comet. SOHO website and NASA having been live blogging and its a little early to know yet if we are going to get a great Christmas comet.

FS Aur is back!

Well, that highly erratic variable cataclysmic variable star FS Aurigae (FS Aur) is back in season and has not disappointed so far with two great outbursts already.

The quiescent duration between outbursts does seem a bit longer than the previous season - so far, but as we saw in the last northern winter, it was prone to springing a few surprises.

More on this soon, Vitaly has a nice slide deck now which he presented at a conference recently.

Regards
Peter

A picture says a thousand words

On my way to the AAVSO Centenary Meeting, I took a little side trip....not really much more to add than that!!! After taking more than a thousand images, I finally got to visit my scope.

Carnival of Space 218

Photo: - Jekert Guapo

Yes its that regular event that comes around once a week which has a webpage hit count that resembles a Cataclysmic Variable Star's light curve....or perhaps a crazy roller coaster.

CARNIVAL OF SPACE!!!! .....and this is a bumper issue.

So Welcome! This week I am live blogging from the AAVSO's Centenary Meeting, celebrating an amazing 100 Years of variable star observations from an incredible organization of dedicated amateur and professional astronomers who have collected and archived 20.7 Million observations (as of yesterday afternoon) since 1911. I cover this event in more depth (below) in my Blog, but just let me share with you this incredible video of the 100 year light curve of SS Cygni.



Its Carnival Time!

Super Novae Buffet!

After the past month's supernova excitement, Laura Chomiuk discusses how Pan-STARRS is shedding light on a new, ultra-luminous type of supernova.

Gianluigi at Doc Madhatten Blog traces the history of supernova research. Starting from the supernovae of Brahe and Galilei, to describe the importance of the supernovae in astronomy research and to tell the Nobel Prize in Physics 2011.
On a side note congratulations to my fellow Australian Brian Schmidt (and Riess & Perlmutter) for the recognition this week from the Nobel committee. Aussie, Aussie Aussie!!!.....ah sorry you have probably heard that too many times in all the wrong places already.

On the same topic - the Minute Physics Channel Guest narrator Sean Carroll of Caltech describes dark energy and the acceleration of the universe, the discovery of which was awarded the 2011 Nobel Prize in Physics on October 4th.


Space Mission Update!

Riofrio Space Time Blog reports on the October 4 anniversary of the launch of Sputnik, an event that affected humanity in ways too numerous to count. Replicas of Sputnik hang in museums like the National Air and Space Museum. At San Francisco's Beat Museum we hear a fascinating tale, that pieces of Sputnik may have been recovered.

At the Weirdwarp Blog - Space Expedition Curacao plans to fly space tourists on sub-orbital trips starting in 2014 at about half the price of Virgin Galactic. Check the safety instructions on the card in the back of the seat here.

Last week, scientists announced findings based on data from the SPICAM spectrometer onboard ESA’s Mars Express spacecraft. Ray Sander's on Universe Today Blog discusses the findings reported in Science by Maltagliati et al (2011), reveal that the Martian atmosphere is super-saturated with water vapor.

Beyond Apollo Blog discusses what self-sufficiency in outer space might look like. In a paper presented in October 1989 at the 40th Congress of the International Astronautical Federation, two veteran space scientists proposed a 10-year program aimed at establishing a self-sufficient science outpost that would serve as testbed for space settlements.

The Urban Astronomer reports on data released by NEOWISE shows that there are fewer mid-sized asteroids in near-Earth orbit than we perviously thought. This means that the risk of a city-busting impact are lower than we thought. Not that that's any reason to become complacent!

With gold at record prices, find your own nuggets and dig for gold in the Chandra archive.

Over at BigThink.com Dr. Kaku addresses a question posed by Steven Lee Spall: Can we build a space elevator?

Space Coalition is running a competition - Dream about space? Make a video and enter to win an iPad 2. The Coalition for Space Exploration is hosting this video/blogging contest.

Vintage Space looks at what really killed the Dyna-Soar: a brief history covering its roots, life, and eventual cancellation. That might be a different Dinosaur to what you're thinking ;-)

Finally in Mission Update a call to action from Habitation Intention explaining how the Apollo age was not the age we where most tempted to quit space exploration, but now is.

Telescopes!
ALMA is up and running!
Image: ALMA (ESO/NAOJ/NRAO)/W. Garnier (ALMA)


Weird Warp opens our coverage of a new telescope starting to look at the universe. ALMA is the most powerful millimetre/submillimetre wavelength telescope in the world. These are longer wavelengths roughly about 1000 times longer than visible light wavelengths. Using these wavelengths ALMA allows astronomers to study really cold objects in the universe such as dense clouds of cosmic dust and gas from which stars and planets form as well as distant objects in the early universe.


ALMA (ESO/NAOJ/NRAO). Visible light image: the NASA/ESA Hubble Space Telescope

Discovery News also covers the first image from the ALMA array.

Bente from Planet Bye also features a number of the first light images.


Credit: NRAO/AUI and J. Hibbard

Armagh Planet visits the Paranal site of European Southern Observatory. Well, if you have ever seen James Bond movie Quantum of Solace then you will have seen a glimpse of this amazing facility! If it’s good enough for Bond, then it must be quite a place, Armagh Planet updates us on exactly what it is, where it is, and what work is done there! (A LOT!)

Solar System(s)!
Next Big Future looks at possible causes of CMEs including whether a comet may have caused a coronal mass ejection. This also relates to an article form Jan,2010 at nextbigfuture which examined the future threat of man made solar explosions causing a super massive coronal mass ejection.

Smaller Questions examines Kepler trends and finds it turns out, Earth-sized planets in habitable zones around low-mass stars are not as rare as Kepler initially led astronomers to believe (not Kepler the guy--he's dead--but Kepler the exoplanet-scouting satellite).

Astronomy Media!
The Space Show: welcomes Dr. David Whitehouse of the UK, the world’s most cited science journalist, to the show to discuss science and space journalism, space policy in the UK, the U.S. and much more.

PortaltotheUniverse is where the whole space community comes together in one place; connect your blogs now for live feeds of your blogs into the Astronomy Community.

Big Think discusses career opportunities in the 21st Century. In this video, Musk describes how he has come to recognize opportunities as an entrepreneur in the space industry, which is one of the core skills necessary for success in the 21st century.

So that is it for Carnival 218! Thanks for dropping by AARTSCOPE where our mission is to - "create the sense of anticipation and discovery that keeps us asking questions".

I leave you with my unique, personal tribute to the AAVSO's 100 years of service to the Astronomy Community!


The Carnival of Space is a community of interest blog carnival bringing together the best and brightest Astronomy & Space Blogs at a single point in space and time (commonly referred to as a web address) each week. Previous episodes can be found here. If you run an astronomy or space science blog you can contact carnivalofspace @ gmail.com to be added to the editorial circulation list.

For a guide on how to prepare an episode of Carnival of Space Habitation Intention has produced a GDoc as a template guide.

AAVSO Centenary Meeting

Legacy, what is it, the heritage you create for those that follow may well be one way of looking at it. The AAVSO's legacy and history is legendary. Today I met with some of those legends, and heros of the AAVSO for the first time, although I have worked with a number of them for a few years already without having ever met them.

The first day of the AAVSO meeting kicked of with the official opening of the new headquarters, and the dedication of the Thomas and Anna Faye Williams archives and Dorrit Hoffleit conference room. What an amazing day!


The ribbon cutting ceremony used a large pair of scissors that were specially made to cut up the original star charts by hand after they were printed.

I heard stories from Charles Scovil who described the first star charts hand drawn on transparent linen with India Ink before being etched by a unique process that involved cynide and would surely not be legal today......amazing. We are talking pre-Xerox days.


Photo: Gerry Samolyk showed off some of his original charts

Charles Alcock from the Smithsonian Center for Astrophysics gave a fascinating keynote on the history and the future of Variable Star Astronomy, where he posed the question are all stars variable if your SNR is good enough?

Perhaps that question will be answered by those who dig up the 50 Year Time Capsule that we prepared for burial. Yes, thats right a copy of the book Advancing Variable Star Astronomy was signed by all attendees with some even writing down messages for their kids. A number of the leaders of the AAVSO wrote personal reflections and questions we posed to see if they have been answered by the next generation of AAVSO members who will open the time capsule in the October meeting 2061.

By far the highlight for me was the 100 year light curve of SS Cygni that circled the walls of the Dorrit Hoffleit Conference room. Incredible - the worlds longest lightcurve with 100 years of observations.


No birthday would be complete without cake and ice cream, and so we caught up, shared stories, met our heros, and compared notes on different observing campaigns.

HAPPY 100th Birthday AAVSO !!!!!!

Become part of the next century's activity and join the AAVSO today!