Just arrived from London from a one-day meeting of the MIRI consortium, I cannot avoid looking back with pride at our achievements, in this longer than 10 years challenge.
At least, to “Cosmic Diaries”. First, thanks to Franck Marchis for all the hard work he has investing setting up the system again.
And back to the Cosmos, since I have starting to do Science, after a lot of time immersed in bureaucratic and more technical work (a 6.5m telescope?).
Last week we had the Calar Alto Time Assigning Committee, which also took a lot of time (reading more than 100 proposals and try to really understand what the intent to do, and the relevance of the science in not an easy task). But this is over now.
Now, real science. At least my own, starting with the inspection of hundreds of spectra already taking for the Gaia-ESO survey. This program aims to understand the properties of stars belonging to open clusters and young stellar associations, as well as the Galaxy as a whole (galactic archaeology). Hundred of nights will be invested with the VLT during the next few years, in order to make the best out of the Gaia satellite (to be launched in Summer 2013) and the wealth of data it will deliver. So, a very exciting project! And, of course, a lot of work.
With my student Jorge Lillo, I have been observing Saturn with the 2.2m telescope and Astralux, a lucky imaging camara capable of delivering images with resolution almost similar to those of the Hubble Space Telescope.
If you do not beleive, have a look…
There are two options (for both types): either they have been formed in a similar way as stars (collapse and fragmentation of molecular clouds, with all their variations -effect of strong winds by massive, nearby stars, dynamical interactions due to close encounters, etc), or in a way similar to the planets in the Solar System (from the material left from the formation of the central star, which is organized as a disk during the first few million years of the star life).
We do not know how the IPMOs (Isolated Planetary Mass Objects) found in Sigma Ori and other regions (Trapezium, Lambda Orionis, etc) have been formed (catalog for confirmed objects). There are several hints, and they point out that they might have formed by the first mechanism (similar to stars). However, even if the majority are formed from collapse and fragmentation, some could be bona fide giant planets, expelled by a close encounter with another star or by the dynamical instabilities within the original planetary system (with other massive planets and/or the original disk surrounding the central star).
In any case, the detection of the new isolated objects by gravitational lensing does not say anything directly about how they were formed. The situation is very similar to the Sigma Ori IPMOs. So, they might be runaway planets or IPMOs formed in a stellar association which has dissolved after several hundred or thousand millions of years (after they have orbited several times around the center of the Galaxy).
However, it is true that in the Sumi’s paper, the results indicate the formation mechanism might be different, based on the number of events. This might suggest they are formed as planets.
We have to take into account that the statistics is poor in both cases, in the sense that the number of detected objects is so low that the error-bars are very important. So more observations are really needed.
So, they might be identical twins (from the perspective of the formation mechanism) or siblings (again, from the same perspective).
2/ What differs between the two types of objects?
Age. The SOri IPMOs are very young (3-5 Myr), whereas the new objects should be very old. In addition, although we do not know for sure, the composition might be different, since the universe is in continuous chemical evolution, being enriched of chemical elements heavier than hydrogen and helium (mainly by the death of massive stars).
In any case, a number of IPMOs identified in young stellar associations have been characterized with spectroscopy, a technique that gives us very interesting information about their nature and properties. The lest massive object identified so far ha a mass about 3 Mjupiter (the micro-lensing IPMOs have about 10 Mjupiter).
3/ Do you have more informations (since 1999) about S Ori 47?
We believe SOri 47 is a very low-mass brown dwarf, slightly above the deuterium burning limit (ie, some possible frontier between BD and IPMOs, based on the easiest of the nuclear reactions).
Planetary Mass Objects (PMO) have been found in different environments. In isolation but inside star forming regions, such as the IPMOs in SOri (ie, no nearby stars, no gravitational link between the object and the PMO), and close to low-mass stars or brown dwarfs.
An example of this last case is 2M1207, discovered by Gael Chavin and collaborators in 2004. A 5 Mjupiter PMO is located about 40 astronomical units from a 20-30 Mjupiter brown dwarf. The system has an age about 10 Myr. A more recent example is the case of T Cha, a low-mass star with a substellar object in formation, located in the middle of the gap of a circunstellar disk.
Eventually (but we do not know if this would happen), the low-mass companion (2M1207b) might be expelled and after thousand of million years, after it cools down, it would look like the objects discovered by gravitational lensing.
4/ Do you think that these free floating planets can be made alone, far away from any interstellar cloud or very young star forming region?
No, they should be formed in dense, rich environments such as the Orion Molecular Cloud and other similar to them. But the statistics are poor. A dozen objects is not significant. As a comparison, we estimate that the number of stars in the Galaxy is two hundred milliards (200,000,000,000).
5/ Do you think that these objects can be part of dark matter? If yes, what percentage?
Indeed, but just an insignificant fraction, not relevant at all. Probably, they do not have any impact on the general gravitational field of the Galaxy. So, they should not be the solution for the dark matter problem.
6/ Please, add any comment you find important about this work!
It quite interesting to apply a different technique and confirm that the dark, empty interstellar space is not so empty after all. On top of this, the mass is estimated more directly (whereas we have to apply theoretical models for the IPMOs found by photometric searches, such as those in Sigma Ori).
However, it is true that this is not the first finding of the type (very low-mass, extremely cool objects). Similar objects have been found in very young stellar associations, just after they have been formed. And more massive siblings, called ultra cool dwarfs, are being discovered in isolation. These objects are also very old, but with masses about 20-70 Mjupiter. They are temperatures are hotter, reaching about 400-600 K. What it is relevant is that we are starting to realize that the Galaxy is filled with a plethora of strange objects which reassemble the Solar System giant planets, but not quite. The new all-sky, deep surveys in the near- and mid-infrared, which are being conducted now, will uncover a significant number of them, even very close to the Solar System (even closer than the nearest star), and new instrumentation, such as the E-ELT, will be used to study their properties.
In any case, the frequency of events, its dependence on the event time scale (how long they last) and its relation with the mass of the objects suggest a different origin (stars and brown dwarfs on one hand, micro-lensing IPMO son the other). The possibility of having runaway planets is, indeed, fascinating.
Amazing results from my friend Nuria Huélamo and her collaborators ….
From the ESO website:
“Using ESO’s Very Large Telescope an international team of astronomers has been able to study the short-lived disc of material around a young star that is in the early stages of making a planetary system. For the first time a smaller companion could be detected that may be the cause of the large gap found in the disc. Future observations will determine whether this companion is a planet or a brown dwarf.”
I recommend the video, wonderful.
Alien, as I said before. As a token, a couple of videos, with the landscape and the residence. The first time I visited, it looked like a research station in Mars. I still have the same feeling. I cannot avoid remembering a science fiction story by John Varley: In the Hall of the Martian Kings.
Perhaps the most impressive thing is the way down to the residence, below the dome. The external ambient is extremely dry. But once you cross the second door, everything changes. Watch and try to imagine the experience:
Anyway, this morning when we were working, preparing the observations for the night, we felt some noise, some vibration. I was not worried, but it was an earthquake.
The earthquake lasted few seconds. Later on, we were informed that it was important: 5.1 int he Richter scale. As a matter of fact, the strongest in the last few days.
A shaky start, just what I needed to wake up completely …
After ten years … again back to Paranal. One of the most amazing observatories in the world, if not the most alien. Mauna Kea in Hawaii is very beautiful, but gentle, with the smooth slopes of the volcanoes. So gentle, that it is difficult to notice the presence of the Mauna Loa, the largest volcano in the world (depending on the definition). Roque de los Muchachos, in La Palma, Spain, may be the more dramatic, hanging from the ridge of the caldera, with the clouds passing by several hundred meters below the observatory, and the Atlantic ocean below then, sometimes visible, sometimes hidden. Calar Alto, also in Spain, and La Serena, Las Campanas o La Silla (these three also in Chile) are like home: comfortable and trustworthy. Probably the places where you want to spend a long observing run. But Paranal has something no other observatory posses: an exo-earth aura, the feeling of being in a space mission, of almost exploring Mars.
Because, indeed, the landscape is very martian: red, sandy hills; extreme cold and hot, and an incredible lack of water, of dryness. Just like the poor, small sibling of Earth. As I said, very alien.
We are here to get spectra of even more “alien worlds”: planetary mass objects located in a distant star-forming region, Orion´s Head. In fact, we want to verify their nature. During the last decade we have been studying this region, trying to get a complete census of its members, from solar-like stars to brown dwarfs, and to establish their properties. We have a large number of planetary mass objects, very young and with properties similar to the giant planets, but presumably formed by a mechanism similar to the stars, collapse and fragmentation of a molecular clouds. By obtaining low-resolution spectroscopy we intent to verify their nature (whether they belong to the association and they do have planetary masses) and to know something about their basic properties.
Half asleep, after almost 24 hours in planes and cars, I arrive at the observatory full of expectations. This time I have been lucky: Iberia put my in business class, a courtesy I do appreciate. It really makes a difference, although I arrived very tired, and the jet-lag is still present. A toll we have to pay for the privilege of being here.
As usual, the sky is clear, cloudless. A promising night is awaiting us …
After many moths and a lot of work …. (and this is one of the reasons why I was not active writing posts, or in science) ….
We have an agreement! Calar Alto Observatory (Almería, Southern Spain) will continue it scientific operations up to the end of 2018. I am attaching the press release.
On December 2nd 2010, the German Max Planck Society (MPG) and Spanish National Research Council (CSIC) have signed an agreement in order to operate the Calar Alto Observatory at the German-Spanish Astronomical Centre during the period 2014-2018. The German-Spanish Astronomical Centre (CAHA) is a joint venture of the German MPG and the Spanish CSIC. Both partners renew their commitment with the German-Spanish Astronomical Centre (CAHA), to mantain the observatory at the forefront of scientific research in the coming years.
The new agreement poses special focus on the development and scientific exploitation of the new CARMENES spectrograph for the 3.5 m telescope. CARMENES (Calar Alto High-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is presently being designed and will be capable of detecting habitable planets similar to Earth around the smallest and coolest stars of the solar neighbourhood in our Galaxy. A minimum of six hundred telescope nights are granted for this search during the five year period.
The German-Spanish Astronomical Centre was born in 1973 through an international agreement between the Federal Republic of Germany and the Kingdom of Spain. The institution operates the most outstanding astronomical observatory placed on continental Europe, whose facilities have played a key role in the development of astronomy in Spain during the last decades. The funding and operation of the Observatory were performed by the Max Planck Society, through its Max Planck Institute for Astronomy (Heidelberg) until the end of 2003. Since 2004, the Calar Alto Observatory is operated jointly by the two partners MPG and CSIC (through its Astrophysical Institute of Andalusia, at Granada). CAHA Director, D. Barrado, states: “The new agreement, signed in 2010, guarantees the future of the Calar Alto Observatory, which will keep its position as a central piece of Spanish and German astronomy for many more years.”
Trying to confirm the proto brown dwarfs … I already have the answer. At least part of it. Weather is not kind to us, at least tonight.
Mean while, several nice pictures, taken with my mobile.
SPITZER TELESCOPE OBSERVES BABY BROWN DWARF
PASADENA, Calif. — NASA’s Spitzer Space Telescope has contributed to the discovery of the youngest brown dwarf ever observed — a finding that, if confirmed, may solve an astronomical mystery about how these cosmic misfits are formed.
Brown dwarfs are misfits because they fall somewhere between planets and stars in terms of their temperature and mass. They are cooler and more lightweight than stars and more massive (and normally warmer) than planets. This has generated a debate among astronomers: Do brown dwarfs form like planets or like stars?
Brown dwarfs are born of the same dense, dusty clouds that spawn stars and planets. But while they may share the same galactic nursery, brown dwarfs are often called “failed” stars because they lack the mass of their hotter, brighter siblings. Without that mass, the gas at their core does not get hot enough to trigger the nuclear fusion that burns hydrogen — the main component of these molecular clouds — into helium. Unable to ignite as stars, brown dwarfs end up as cooler, less luminous objects that are more difficult to detect — a challenge that was overcome in this case by Spitzer’s heat-sensitive infrared vision.
To complicate matters, young brown dwarfs evolve rapidly, making it difficult to catch them when they are first born. The first brown dwarf was discovered in 1995 and, while hundreds have been discovered since, astronomers had not been able to unambiguously find them in their earliest stages of formation until now. In this study, an international team of astronomers found a so-called “proto brown dwarf” while it was still hidden in its natal star-forming region. Guided by Spitzer data collected in 2005, they focused their search in the dark cloud Barnard 213, a region of the Taurus-Auriga complex well known to astronomers as a hunting ground for young objects.
“We decided to go several steps back in the process when (brown dwarfs) are really hidden,” said David Barrado of the Centro de Astrobiología in Madrid, Spain, lead author of the paper on the discovery in the Astronomy & Astrophysics journal. “During this step they would have an (opaque) envelope, a cocoon, and they would be easier to identify due to their strong infrared excesses. We have used this property to identify them. This is where Spitzer plays an important role because Spitzer can have a look inside these clouds. Without it this wouldn’t have been possible.”
Spitzer’s longer-wavelength infrared camera penetrated the dusty natal cloud to observe a baby brown dwarf named SSTB213 J041757. The data, confirmed with near-infrared imaging from Calar Alto observatory, revealed not one but two of what would potentially prove to be the faintest and coolest brown dwarfs ever observed.
Barrado and his team embarked on an international quest for more information about the two objects. Their overarching scientific objective was to observe and characterize the presence of this dusty envelope – proof of the celestial womb of sorts that would indicate that these brown dwarfs were, in fact, in their earliest evolutionary stages.
The twins were observed from around the globe, and their properties were measured and analyzed using a host of powerful astronomical tools. One of the astronomers’ stops was the Caltech Submillimeter Observatory in Hawaii, which captured the presence of the envelope around the young objects. That information, coupled with what they had from Spitzer, enabled the astronomers to build a spectral energy distribution – a diagram that shows the amount of energy that is emitted by the objects in each wavelength.
From Hawaii, the astronomers made additional stops at observatories in Spain (Calar Alto Observatory), Chile (Very Large Telescopes) and in New Mexico (Very Large Array). They also pulled decade-old data from the Canadian Astronomy Data Centre archives that allowed them to comparatively measure how the two objects were moving in the sky. After more than a year of observations, they drew their conclusions.
“We were able to estimate that these two objects are the faintest and coolest discovered so far,” Barrado said. Barrado said the findings potentially solve the mystery about whether brown dwarfs form more like stars or planets. The answer? They form like low-mass stars. This theory is bolstered, because the change in brightness of the objects at various wavelengths matches that of other very young, low-mass stars.
While further study will confirm whether these two celestial objects are in fact proto brown dwarfs, they are the best candidates so far, Barrado said. He said the journey to their discovery, while difficult, was “fun. “It is a story that has been unfolding piece by piece. Sometimes nature takes its time it give up its secrets.”
The paper’s other authors are M. Morales-Calderon, Centro de Astrobiología and Spitzer Science Center; A. Palau and A. Bayo, Centro de Astrobiología; I. de Gregorio-Monsalvo, European Southern Observatory; C. Eiroa, Universidad Autónoma de Madrid; N. Huelamo, Centro de Astrobiología; H. Bouy, Instituto de Astrofísica de Canarias and European Space Agency; O. Morata, Institute of Astronomy and Astrophysics and National Taiwan Normal University; and L. Schmidtobreick, European Southern Observatory. More information on the Spitzer Space Telescope is online at http://spitzer.caltech.edu and http://www.nasa.gov/spitzer.