* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Kuiper Belt


L

Posts: 131433
Date:
Kuiper Belt Object Occultations
Permalink  
 


Title: Kuiper Belt Object Occultations: Expected Rates, False Positives, and Survey Design
Authors: Steven Bickerton, Doug Welch, JJ Kavelaars

A novel method of generating artificial scintillation noise is developed and used to evaluate occultation rates and false positive rates for surveys probing the Kuiper Belt with the method of serendipitous stellar occultations. A thorough examination of survey design shows that: (1) diffraction-dominated occultations are critically (Nyquist) sampled at a rate of 2 Fsu^{-1}, corresponding to 40 s^{-1} for objects at 40 AU, (2) occultation detection rates are maximized when targets are observed at solar opposition, (3) Main Belt Asteroids will produce occultations lightcurves identical to those of Kuiper Belt Objects if target stars are observed at solar elongations of: 116 deg < epsilon < 125 deg, or 131 deg < epsilon < 141 deg, and (4) genuine KBO occultations are likely to be so rare that a detection threshold of >7-8 sigma should be adopted to ensure that viable candidate events can be disentangled from false positives.

Read more  (168kb, PDF)

__________________


L

Posts: 131433
Date:
RE: Kuiper Belt
Permalink  
 


Distant Minor Planets For 2009 Feb. 28

MPEC 2009 -C70

__________________


L

Posts: 131433
Date:
Distant Minor Planets
Permalink  
 


Distant Minor Planets (2009 Jan. 29.0 TT)

MPEC 2009 -A63

__________________


L

Posts: 131433
Date:
RE: Kuiper Belt
Permalink  
 


Title: The Size Distribution of Kuiper belt objects for D> 10 km
Authors: W. C. Fraser (University of Victoria, California Institute of Technology), J. J. Kavelaars (Herzberg Institute for Astrophysics)

We have performed a survey of the Kuiper belt covering ~ 1/3 a square degree of the sky using Suprime-cam on the Subaru telescope, to a limiting magnitude of m(R)~ 26.8 (50% threshold) and have found 36 new KBOs. We have confirmed that the luminosity function of the Kuiper belt must break as previously observed (Bernstein et al. 2004; Fuentes & Holman 2008). From the luminosity function, we have inferred the underlying size distribution and find that it is consistent with a large object power-law slope q1~4.8 that breaks to a slope q2~1.9 at object diameter Db~60 km assuming 6% albedos. We have found no conclusive evidence that the size distribution of KBOs with inclinations i<5 is different than that of those with i>5. We discuss implications of this measurement for early accretion in the outer solar system and Neptune migration scenarios.

Read more (62kb, PDF)

__________________


L

Posts: 131433
Date:
Permalink  
 

The hunt continues for the outer solar system's tiniest residents. A two-year search to find small objects there has turned up nothing, bolstering theories that 'all hell broke loose' in the solar system just a few hundred million years after it formed.
Astronomers have found more than 1000 objects in the Kuiper Belt, a ring of icy bodies beyond Neptune. There are fewer large Kuiper Belt Objects than smaller ones, but the exact size distribution is unknown because only a handful of KBOs smaller than 70 kilometres across have been found they simply reflect too little sunlight to be observed.
The smallest KBOs seen so far measure about 30 km across and were found five years ago using the Hubble Space Telescope. But only a few were seen 25 times more of the small objects had been predicted based on the size distribution of larger KBOs.

Source

__________________


L

Posts: 131433
Date:
Permalink  
 

Outer Solar System Not as Crowded as Astronomers Thought
When a treasure hunt comes up empty-handed, the hunters are understandably disappointed. But when astronomers don't find what they are looking for, the defeat can provide as much information as a successful search.
The search in question, the Taiwanese-American Occultation Survey (TAOS), spent two years periodically photographing portions of the sky to look for small chunks of rock and ice orbiting beyond Neptune, in a region of the solar system called the Kuiper Belt. The survey targeted Kuiper Belt objects (KBOs) with sizes between 2 miles (3 km) and 17 miles (28 km).
Since such objects are too small to see directly, the survey watched for stars to dim as KBOs passed in front of and occulted them. After accumulating more than 200 hours of data watching for stellar flickers lasting a second or less, TAOS did not spot any occultations.

Read more

__________________


L

Posts: 131433
Date:
Permalink  
 

Title: The Kuiper Belt and Other Debris Disks
Authors: David Jewitt, Amaya Moro-Martín, Pedro Lacerda

We discuss the current knowledge of the Solar system, focusing on bodies in the outer regions, on the information they provide concerning Solar system formation, and on the possible relationships that may exist between our system and the debris disks of other stars. Beyond the domains of the Terrestrial and giant planets, the comets in the Kuiper belt and the Oort cloud preserve some of our most pristine materials. The Kuiper belt, in particular, is a collisional dust source and a scientific bridge to the dusty "debris disks" observed around many nearby main-sequence stars. Study of the Solar system provides a level of detail that we cannot discern in the distant disks while observations of the disks may help to set the Solar system in proper context.

Read more (1737kb, PDF)

__________________


L

Posts: 131433
Date:
Permalink  
 

Title: Colour-Inclination Relation of the Classical Kuiper Belt Objects
Authors: Nuno Peixinho, Pedro Lacerda, David Jewitt

We re-examine the correlation between the colours and the inclinations of the Classical Kuiper Belt Objects (CKBOs) with an enlarged sample of optical measurements. The correlation is strong (rho=-0.7) and highly significant (>8 sigma) in the range 0-34 deg. Nonetheless, the optical colours are independent of inclination below ~12 deg, showing no evidence for a break at the reported boundary between the so-called dynamically "hot" and "cold" populations near ~5 deg. The commonly accepted parity between the dynamically cold CKBOs and the red CKBOs is observationally unsubstantiated, since the group of red CKBOs extends to higher inclinations. Our data suggest, however, the existence of a different colour break. We find that the functional form of the colour-inclination relation is most satisfactorily described by a non-linear and stepwise behaviour with a colour break at ~12 deg. Objects with inclinations >12 deg show bluish colours which are either weakly correlated with inclination or are simply homogeneously blue, whereas objects with inclinations <12 deg are homogeneously red.

Read more (126kb, PDF)

__________________


L

Posts: 131433
Date:
Permalink  
 

Title: The Warped Plane of the Classical Kuiper Belt
Authors: Eugene Chiang, Hyomin Choi
(Version v2)

By numerically integrating the orbits of the giant planets and of test particles over a period of four billion years, we follow the evolution of the location of the midplane of the Kuiper belt. The Classical Kuiper belt conforms to a warped sheet that precesses with a 1.9 Myr period. The present-day location of the Kuiper belt plane can be computed using linear secular perturbation theory: the local normal to the plane is given by the theory's forced inclination vector, which is specific to every semimajor axis. The Kuiper belt plane does not coincide with the invariable plane, but deviates from it by up to a few degrees in stable zones. For example, at a semimajor axis of 38 AU, the local Kuiper belt plane has an inclination of 1.9 deg and a longitude of ascending node of 149.9 deg when referred to the mean ecliptic and equinox of J2000. At a semimajor axis of 43 AU, the local plane has an inclination of 1.9 deg and a nodal longitude of 78.3 deg. Only at infinite semimajor axis does the Kuiper belt plane merge with the invariable plane, whose inclination is 1.6 deg and nodal longitude is 107.7 deg. A Kuiper belt object keeps its inclination relative to the Kuiper belt plane nearly constant, even while the latter plane departs from the trajectory predicted by linear theory. The constancy of relative inclination reflects the undamped amplitude of free oscillation. Current observations of Classical Kuiper belt objects are consistent with the plane being warped by the giant planets alone, but the sample size will need to increase by a few times before confirmation exceeds 3-sigma in confidence. In principle, differences between the theoretically expected plane and the observed plane could be used to infer as yet unseen masses orbiting the Sun, but carrying out such a program would be challenging.

Read more (378kb, PDF)

__________________


L

Posts: 131433
Date:
Permalink  
 

Title: The Warped Plane of the Classical Kuiper Belt
Authors: Eugene Chiang, Hyomin Choi

By numerically integrating the orbits of the giant planets and of test particles for four billion years, we follow the evolution of the location of the midplane of the Kuiper belt. The Classical Kuiper belt conforms to a warped sheet that precesses with a 1.9 Myr period. The present-day location of the Kuiper belt plane can be computed using linear secular perturbation theory: the local normal to the plane is given by the theory's forced inclination vector, which is specific to every semi-major axis. The Kuiper belt plane does not coincide with the invariable plane, but deviates from it by up to a few degrees in stable zones. A Kuiper belt object keeps its free inclination relative to the Kuiper belt plane nearly constant, even while the plane departs from the trajectory predicted by linear theory. The constancy of free inclination simply reflects the undamped amplitude of free oscillation. Current observations of Classical Kuiper belt objects are consistent with the plane being warped by the giant planets alone, but the sample size will need to increase by a few times before confirmation exceeds 3-sigma in confidence. In principle, differences between the theoretically expected plane and the observed plane could be used to infer as yet unseen masses orbiting the Sun, but carrying out such a program would be challenging.

Read more (378kb, PDF)

__________________
«First  <  1 2 3 4 5 6  >  Last»  | Page of 6  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard