46 research outputs found
Migratory Outbursting Quasi-Hilda Object 282P/(323137) 2003 BM80
We report object 282P/(323137) 2003 BM80 is undergoing a sustained activity
outburst, lasting over 15 months thus far. These findings stem in part from our
NASA Partner Citizen Science project Active Asteroids
(http://activeasteroids.net), which we introduce here. We acquired new
observations of 282P via our observing campaign (Vatican Advanced Technology
Telescope, Lowell Discovery Telescope, and the Gemini South telescope),
confirming 282P was active on UT 2022 June 7, some 15 months after 2021 March
images showed activity in the 2021/2022 epoch. We classify 282P as a member of
the Quasi-Hilda Objects, a group of dynamically unstable objects found in an
orbital region similar to, but distinct in their dynamical characteristics to,
the Hilda asteroids (objects in 3:2 resonance with Jupiter). Our dynamical
simulations show 282P has undergone at least five close encounters with Jupiter
and one with Saturn over the last 180 years. 282P was most likely a Centaur or
Jupiter Family Comet (JFC) 250 years ago. In 350 years, following some 15
strong Jovian interactions, 282P will most likely migrate to become a JFC or,
less likely, a main-belt asteroid. These migrations highlight a dynamical
pathway connecting Centaurs and JFC with Quasi-Hildas and, potentially, active
asteroids. Synthesizing these results with our thermodynamical modeling and new
activity observations, we find volatile sublimation is the primary activity
mechanism. Observations of a quiescent 282P, which we anticipate will be
possible in 2023, will help confirm our hypothesis by measuring a rotation
period and ascertaining spectral type.Comment: 23 pages, 5 figure
Population and Size Distribution of Small Jovian Trojan Asteroids
We present a study of Jovian Trojan objects detected serendipitously during
the course of a sky survey conducted at the University of Hawaii 2.2-meter
telescope. We used a 8192 x 8192 pixel charge-coupled device (CCD) mosaic to
observe 20 deg^2 at locations spread over the L4 Lagrangian swarm and reached a
limiting magnitude V = 22.5 mag (50% of maximum detection efficiency).
Ninety-three Jovian Trojans were detected with radii 2 - 20 km (assumed albedo
0.04). Their differential magnitude distribution has a slope of 0.40 +/- 0.05
corresponding to a power law size distribution index 3.0 +/- 0.3 (1-sigma). The
total number of L4 Trojans with radii > 1 km is of order 1.6 x 10^5 and their
combined mass (dominated by the largest objects) is ~ 10^{-4} M_{Earth}. The
bias-corrected mean inclination is 13.7 +/- 0.5 deg. We also discuss the size
and spatial distribution of the L4 swarm.Comment: 21 pages, 11 figures. AJ, in pres
Properties of the Trans-Neptunian Belt: Statistics From the CFHT Survey
We present the results of a wide-field survey designed to measure the size,
inclination, and radial distributions of Kuiper Belt Objects (KBOs). The survey
found 86 KBOs in 73 square degrees observed to limiting red magnitude 23.7
using the Canada-France-Hawaii Telescope and the 12k x 8k CCD Mosaic camera.
For the first time, both ecliptic and off-ecliptic fields were examined to more
accurately constrain the inclination distribution of the KBOs. The survey data
were processed using an automatic moving object detection algorithm, allowing a
careful characterization of the biases involved. In this work, we quantify
fundamental parameters of the Classical KBOs (CKBOs), the most numerous objects
found in our sample, using the new data and a maximum likelihood simulation.
Deriving results from our best-fit model, we find that the size distribution
follows a differential power law with exponent q = 4.0 (+0.6)(-0.5) (1 sigma,
or 68.27% confidence). In addition, the CKBOs inhabit a very thick disk
consistent with a Gaussian distribution of inclinations with a Half-Width of
i(1/2) = 20 (+6)(-4) deg (1 sigma). We estimate that there are N = 3.8
(+2.0)(-1.5) x 10^4 (1 sigma) CKBOs larger than 100 km in diameter. We also
find compelling evidence for an outer edge to the CKBOs at heliocentric
distance R = 50 AU.Comment: To be published in the Astronomical Journal, July 200
A Wide-Field CCD Survey for Centaurs and Kuiper Belt Objects
A modified Baker-Nunn camera was used to conduct a wide-field survey of 1428
square degrees of sky near the ecliptic in search of bright Kuiper Belt objects
and Centaurs. This area is an order of magnitude larger than any previously
published CCD survey for Centaurs and Kuiper Belt Objects. No new objects
brighter than red magnitude m=18.8 and moving at a rate 1"/hr to 20"/hr were
discovered, although one previously discovered Centaur 1997 CU26 Chariklo was
serendipitously detected. The parameters of the survey were characterized using
both visual and automated techniques. From this survey the empirical projected
surface density of Centaurs was found to be SigmaCentaur(m<18.8)=7.8(+16.0
-6.6)x10^-4 per square degree and we found a projected surface density 3sigma
upper confidence limit for Kuiper Belt objects of SigmaKBO(m< 18.8)<4.1x10^-3
per square degree. We discuss the current state of the cumulative luminosity
functions of both Centaurs and Kuiper Belt objects. Through a Monte Carlo
simulation we show that the size distribution of Centaurs is consistent with a
q=4 differential power law, similar to the size distribution of the parent
Kuiper Belt Objects. The Centaur population is of order 10^7 (radius > 1 km)
assuming a geometric albedo of 0.04. About 100 Centaurs are larger than 50 km
in radius, of which only 4 are presently known. The current total mass of the
Centaurs is 10^-4 Earth Masses. No dust clouds were detected resulting from
Kuiper Belt object collisions, placing a 3sigma upper limit <600 collisionally
produced clouds of m<18.8 per year.Comment: 13 pages, 5 figures, Accepted for Publication in A
Discovery of Dust Emission Activity Emanating from Main-belt Asteroid 2015 FW412
We present the discovery of activity emanating from main-belt asteroid 2015
FW412, a finding stemming from the Citizen Science project Active Asteroids, a
NASA Partner program. We identified a pronounced tail originating from 2015
FW412 and oriented in the anti-motion direction in archival Blanco 4-m (Cerro
Tololo Inter-American Observatory, Chile) Dark Energy Camera (DECam) images
from UT 2015 April 13, 18, 19, 21 and 22. Activity occurred near perihelion,
consistent with the main-belt comets (MBCs), an active asteroid subset known
for sublimation-driven activity in the main asteroid belt; thus 2015 FW412 is a
candidate MBC. We did not detect activity on UT 2021 December 12 using the
Inamori-Magellan Areal Camera and Spectrograph (IMACS) on the 6.5 m Baade
telescope, when 2015 FW412 was near aphelion.Comment: 4 pages, 1 figur
Gemini multi-conjugate adaptive optics system review II: Commissioning, operation and overall performance
The Gemini Multi-conjugate Adaptive Optics System - GeMS, a facility
instrument mounted on the Gemini South telescope, delivers a uniform, near
diffraction limited images at near infrared wavelengths (0.95 microns- 2.5
microns) over a field of view of 120 arc seconds. GeMS is the first sodium
layer based multi laser guide star adaptive optics system used in astronomy. It
uses five laser guide stars distributed on a 60 arc seconds square
constellation to measure for atmospheric distortions and two deformable mirrors
to compensate for it. In this paper, the second devoted to describe the GeMS
project, we present the commissioning, overall performance and operational
scheme of GeMS. Performance of each sub-system is derived from the
commissioning results. The typical image quality, expressed in full with half
maximum, Strehl ratios and variations over the field delivered by the system
are then described. A discussion of the main contributor to performance
limitation is carried-out. Finally, overheads and future system upgrades are
described.Comment: 20 pages, 11 figures, accepted for publication in MNRA
The DECam Ecliptic Exploration Project (DEEP) II. Observational Strategy and Design
We present the DECam Ecliptic Exploration Project (DEEP) survey strategy
including observing cadence for orbit determination, exposure times, field
pointings and filter choices. The overall goal of the survey is to discover and
characterize the orbits of a few thousand Trans-Neptunian Objects (TNOs) using
the Dark Energy Camera (DECam) on the Cerro Tololo Inter-American Observatory
(CTIO) Blanco 4 meter telescope. The experiment is designed to collect a very
deep series of exposures totaling a few hours on sky for each of several 2.7
square degree DECam fields-of-view to achieve a magnitude of about 26.2 using a
wide VR filter which encompasses both the V and R bandpasses. In the first
year, several nights were combined to achieve a sky area of about 34 square
degrees. In subsequent years, the fields have been re-visited to allow TNOs to
be tracked for orbit determination. When complete, DEEP will be the largest
survey of the outer solar system ever undertaken in terms of newly discovered
object numbers, and the most prolific at producing multi-year orbital
information for the population of minor planets beyond Neptune at 30 au.Comment: 29 pages, 4 figures and 4 table
A Deep and Wide Twilight Survey for Asteroids Interior to Earth and Venus
We are conducting a survey using twilight time on the Dark Energy Camera with the Blanco 4 m telescope in Chile to look for objects interior to Earth's and Venus' orbits. To date we have discovered two rare Atira/Apohele asteroids, 2021 LJ4 and 2021 PH27, which have orbits completely interior to Earth's orbit. We also discovered one new Apollo-type Near Earth Object (NEO) that crosses Earth's orbit, 2022 AP7. Two of the discoveries have diameters ≳1 km. 2022 AP7 is likely the largest Potentially Hazardous Asteroid (PHA) discovered in about eight years. To date we have covered 624 square degrees of sky near to and interior to the orbit of Venus. The average images go to 21.3 mag in the r band, with the best images near 22nd mag. Our new discovery 2021 PH27 has the smallest semimajor axis known for an asteroid, 0.4617 au, and the largest general relativistic effects (53 arcsec/century) known for any body in the solar system. The survey has detected ∼15% of all known Atira NEOs. We put strong constraints on any stable population of Venus co-orbital resonance objects existing, as well as the Atira and Vatira asteroid classes. These interior asteroid populations are important to complete the census of asteroids near Earth, including some of the most likely Earth impactors that cannot easily be discovered in other surveys. Comparing the actual population of asteroids found interior to Earth and Venus with those predicted to exist by extrapolating from the known population exterior to Earth is important to better understand the origin, composition, and structure of the NEO population.D.T. was supported by NASA grant 80NSSC21K0807. P.P. was supported by NASA ISFM EIMM award, the NASA Cooperative Agreement 80GSFC21M0002 and NASA solar system Workings award 80NSSC21K0153. T.S.R. acknowledges funding from the NEO-MAPP project (H2020-EU-2-1-6/870377). C.M. was partially supported by the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation, on behalf of the Gemini partnership of Argentina, Brazil, Canada, Chile, the Republic of Korea, and the United States of America. This work was (partially) funded by the Spanish MICIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe" by the "European Union" through grant RTI2018-095076-B-C21, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia María de Maeztu') through grant CEX2019-000918-M