* Astronomy

Members Login
Post Info TOPIC: Exoplanet moons


L

Posts: 131433
Date:
RE: Exoplanet moons
Permalink  
 


Title: Signals of exomoons in averaged light curves of exoplanets
Authors: A.E. Simon, Gy.M. Szabó, L.L. Kiss, K. Szatmáry

The increasing number of transiting exoplanets sparked a significant interest in discovering their moons. Most of the methods in the literature utilize timing analysis of the raw light curves. Here we propose a new approach for the direct detection of a moon in the transit light curves via the so called Scatter Peak. The essence of the method is the valuation of the local scatter in the folded light curves of many transits. We test the ability of this method with different simulations: Kepler "short cadence", Kepler "long cadence", ground-based millimagnitude photometry with 3-min cadence, and the expected data quality of the planned ESA mission of PLATO. The method requires ~100 transit observations, therefore applicable for moons of 10-20 day period planets, assuming 3-4-5 year long observing campaigns with space observatories. The success rate for finding a 1 R_Earth moon around a 1 R_Jupiter exoplanet turned out to be quite promising even for the simulated ground-based observations, while the detection limit of the expected PLATO data is around 0.4 R_Earth. We give practical suggestions for observations and data reduction to improve the chance of such a detection: (i) transit observations must include out-of-transit phases before and after a transit, spanning at least the same duration as the transit itself; (ii) any trend filtering must be done in such a way that the preceding and following out-of-transit phases remain unaffected.

Read more (411kb, PDF)



__________________


L

Posts: 131433
Date:
Permalink  
 

Planets With Stabilizing Moons May Be Common

A team of researchers simulated the formation of hundreds of planets. And they found that nearly half of them experience giant impacts that produce a stabilizing moon. Almost 10 percent wind up with a massive moon comparable to our own. The research appears in the journal Icarus.
Read more



__________________


L

Posts: 131433
Date:
Permalink  
 

Moons like Earth's could be more common than we thought

About one in 10 rocky planets around stars like our Sun may host a moon proportionally as large as Earth's, researchers say.
Our Moon is disproportionately large - more than a quarter of Earth's diameter - a situation once thought to be rare.
Using computer simulations of planet formation, researchers have now shown that the grand impacts that resulted in our Moon may in fact be common.
The result may also help identify other planets that are hospitable to life.

Read more 



__________________


L

Posts: 131433
Date:
Permalink  
 

Title: The fate of moons of close-in giant exoplanets
Authors: Fathi Namouni

We show that the fate of moons of a close-in giant planet is mainly determined by the migration history of the planet in the protoplanetary disk. As the planet migrates in the disk from beyond the snow line towards a multi-day period orbit, the formed and forming moons become unstable as the planet's sphere of influence shrinks. Disk-driven migration is faster than the moons' tidal orbital evolution. Moons are eventually ejected from around close-in exoplanets or forced into collision with them before tides from the star affect their orbits. If moons are detected around close-in exoplanets, they are unlikely to have been formed in situ, instead they were captured from the protoplanetary disk on retrograde orbits around the planets.

Read more (50kb, PDF)

__________________


L

Posts: 131433
Date:
Permalink  
 

Already researchers are locating giant planets far enough from the gravitational pull of their host star to potentially harbour stable satellites. In the May 20 issue of The Astrophysical Journal, a group will report locating a Saturn-mass planet in its star's so-called habitable zone - the temperate ring around a star within which orbiting bodies could harbour liquid water.

"It's more than likely the planet has moons," says the study's lead author Nader Haghighipour, a planetary astronomer with the Institute for Astronomy and the NASA Astrobiology Institute at the University of HawaiiManoa.
But because the newfound planet, HIP 57050 b, is only Saturn-size rather than, say, the size of Jupiter or larger, any moons it may have are probably rather small and not especially planetlike.

Read more

__________________


L

Posts: 131433
Date:
Permalink  
 

With NASA's Kepler mission showing the potential to detect Earth-sized objects, habitable moons may soon become science fact. If we find them nearby, a new paper by Smithsonian astronomer Lisa Kaltenegger shows that the James Webb Space Telescope (JWST) will be able to study their atmospheres and detect key gases like carbon dioxide, oxygen, and water vapour.
So far, planet searches have spotted hundreds of Jupiter-sized objects in a range of orbits. Gas giants, while easier to detect, could not serve as homes for life as we know it. However, scientists have speculated whether a rocky moon orbiting a gas giant could be life-friendly, if that planet orbited within the star's habitable zone (the region warm enough for liquid water to exist).

Read more

__________________


L

Posts: 131433
Date:
Permalink  
 

Senior NAU astronomy major Arron Shiffe is leading one of two teams of astronomy students in a search to find moons orbiting extrasolar planets. While just over 400 planets have been found orbiting other stars in our galaxy, no one has ever detected a moon around one of those planets.

"An exomoon would be incredibly difficult to detect and would require an immense amount of data. But as more and more data comes in, the chances of detecting one will increase" - Kimberly Ward-Duong, fellow astronomy undergraduate, who is leading the other student team.

Read more

__________________


L

Posts: 131433
Date:
Habitable-zone exomoons
Permalink  
 


Title: Pathways Towards Habitable Moons
Authors: David M. Kipping, Stephen J. Fossey, Giammarco Campanella, Jean Schneider, Giovanna Tinetti

The search for life outside of the Solar System should not be restricted to exclusively planetary bodies; large moons of extrasolar planets may also be common habitable environments throughout the Galaxy. Extrasolar moons, or exomoons, may be detected through transit timing effects induced onto the host planet as a result of mutual gravitational interaction. In particular, transit timing variations (TTV) and transit duration variations (TDV) are predicted to produce a unique exomoon signature, which is not only easily distinguished from other gravitational perturbations, but also provides both the period and mass of an exomoon. Using these timing effects, photometry greater or equal to that of the Kepler Mission is readily able to detect habitable-zone exomoons down to 0.2 Earth masses and could survey up to 25,000 stars for 1 Earth-mass satellites. We discuss future possibilities for spectral retrieval of such bodies and show that transmission spectroscopy with JWST should be able to detect molecular species with ~30 transit events, in the best cases.

Read more (22kb, PDF)

__________________


L

Posts: 131433
Date:
RE: Exoplanet moons
Permalink  
 


Detecting Life-Friendly Moons
The search for life-friendly real estate around distant stars doesn't have to be limited to planets. New research shows that habitable exomoons can be detected with a new method using current technology.

Read more

__________________


L

Posts: 131433
Date:
Exomoons
Permalink  
 


Title: The search for exomoons and the characterisation of exoplanet atmospheres
Authors: Giammarco Campanella

Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. A review on the current situation of exoplanet characterisation is presented in Chapter 3. We focus on the characterisation of transiting planets orbiting very close to their parent star since for them we can already probe their atmospheric constituents. By contrast, the second part of the Chapter is dedicated to the search for extraterrestrial life, both within and beyond the Solar System. The characteristics of the Habitable Zone and the markers for the presence of life (biosignatures) are detailed. In Chapter 4 we describe the primary transit observations of the hot Jupiter HD 209458b we obtained at 3.6, 4.5, 5.8 and 8.0 micron using IRAC/Spitzer. Chapter 5 is dedicated to the search for exomoons, we review a model for the TTV and TDV signals which permits not only the identification of exomoons but also the derivation of some of their characteristics. Finally, in Chapter 6 the detectability of a habitable-zone exomoon around various configurations of exoplanetary systems with the Kepler Mission or photometry of approximately equal quality is investigated. We find that habitable-zone exomoons down to 0.2 Earth Masses may be detected.

Read more (4670kb, PDF)

__________________
«First  <  1 2 3  >  Last»  | Page of 3  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard