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131. New extreme trans-Neptunian objects
ID:
ivo://CDS.VizieR/J/AJ/152/221
Title:
New extreme trans-Neptunian objects
Short Name:
J/AJ/152/221
Date:
21 Oct 2021
Publisher:
CDS
Description:
We are performing a wide and deep survey for extreme distant solar system objects. Our goal is to understand the high-perihelion objects Sedna and 2012 VP113 and determine if an unknown massive planet exists in the outer solar system. The discovery of new extreme objects from our survey of some 1080 square degrees of sky to over 24th magnitude in the r-band are reported. Two of the new objects, 2014 SR349 and 2013 FT28, are extreme detached trans-Neptunian objects, which have semimajor axes greater than 150 au and perihelia well beyond Neptune (q>40au). Both new objects have orbits with arguments of perihelia within the range of the clustering of this angle seen in the other known extreme objects. One of these objects, 2014 SR349, has a longitude of perihelion similar to the other extreme objects, but 2013 FT28 is about 180{deg} away or anti-aligned in its longitude of perihelion. We also discovered the first outer Oort Cloud object with a perihelion beyond Neptune, 2014 FE72. We discuss these and other interesting objects discovered in our ongoing survey. All the high semimajor axis (a>150au) and high-perihelion (q>35au) bodies follow the previously identified argument of perihelion clustering as first reported and explained as being from an unknown massive planet in 2014 by Trujillo & Sheppard, which some have called Planet X or Planet Nine. With the discovery of 2013 FT28 on the opposite side of the sky, we now report that the argument of perihelion is significantly correlated with the longitude of perihelion and orbit pole angles for extreme objects and find there are two distinct extreme clusterings anti-aligned with each other. This previously unnoticed correlation is further evidence of an unknown massive planet on a distant eccentric inclined orbit, as extreme eccentric objects with perihelia on opposite sides of the sky (180{deg} longitude of perihelion differences) would approach the inclined planet at opposite points in their orbits, thus making the extreme objects prefer to stay away from opposite ecliptic latitudes to avoid the planet (i.e., opposite argument of perihelia or orbit pole angles).
132. NIR albedos of main-belt asteroids
ID:
ivo://CDS.VizieR/J/ApJ/791/121
Title:
NIR albedos of main-belt asteroids
Short Name:
J/ApJ/791/121
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present revised near-infrared albedo fits of 2835 main-belt asteroids observed by WISE/NEOWISE over the course of its fully cryogenic survey in 2010. These fits are derived from reflected-light near-infrared images taken simultaneously with thermal emission measurements, allowing for more accurate measurements of the near-infrared albedos than is possible for visible albedo measurements. Because our sample requires reflected light measurements, it undersamples small, low-albedo asteroids, as well as those with blue spectral slopes across the wavelengths investigated. We find that the main belt separates into three distinct groups of 6%, 16%, and 40% reflectance at 3.4 {mu}m. Conversely, the 4.6 {mu}m albedo distribution spans the full range of possible values with no clear grouping. Asteroid families show a narrow distribution of 3.4 {mu}m albedos within each family that map to one of the three observed groupings, with the (221) Eos family being the sole family associated with the 16% reflectance 3.4 {mu}m albedo group. We show that near-infrared albedos derived from simultaneous thermal emission and reflected light measurements are important indicators of asteroid taxonomy and can identify interesting targets for spectroscopic follow-up.
133. NIR spectra of Centaurs and Kuiper Belt objects
ID:
ivo://CDS.VizieR/J/AJ/135/55
Title:
NIR spectra of Centaurs and Kuiper Belt objects
Short Name:
J/AJ/135/55
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present here an extensive survey of near-infrared (NIR) spectra of Kuiper belt objects (KBOs) and Centaurs taken with the Keck I Telescope. We find that most spectra in our sample are well characterized by a combination of water ice and a featureless continuum. A comparative analysis reveals that the NIR spectral properties have little correlation to the visible colors or albedo, with the exception of the fragment KBOs produced from the giant impact on 2003 E
134. Non-gravitational effects in retrograde orbits
ID:
ivo://CDS.VizieR/J/A+A/646/A182
Title:
Non-gravitational effects in retrograde orbits
Short Name:
J/A+A/646/A182
Date:
21 Oct 2021
Publisher:
CDS
Description:
Dynamical studies of asteroid populations in retrograde orbits, i.e. with orbital inclinations greater than 90 degrees, are interesting because the origin of such orbits is still unexplained. Generally, the retrograde asteroids population includes mostly Centaurs and transneptunian objects (TNOs). A special case is the Near Earth Object (343158) 2009 HC82 from the Apollo group. Another interesting object is the comet 333P/LINEAR, which for several years was considered as the second retrograde object approaching Earth. One more comet in retrograde orbit, 161P Hartley/IRAS appears to be an object of similar type. Thanks to the large amount of observational data for these two comets, we tested various models of cometary non-gravitational forces applied to their dynamics. The goal was to estimate which of non-gravitational perturbations could affect the stability of retrograde bodies. In principle, we study the local stability by measuring the divergence of nearby orbits. We have numerically determined Lyapunov chaotic indicators (LCI) and the associated Lyapunov times (LT). This time, our calculations of these parameters were extended by more advanced models of non-gravitational perturbations (i.e. Yarkovsky drift and in selected cases cometary forces). This allowed estimating the chaos in the Lyapunov sense. We found that the Yarkovsky effect for obliquities of gamma=0{deg} and gamma=180{deg} can change LT substantially. In most cases, for the prograde rotation, we received more stable solutions. Moreover, we confirmed the role of retrograde resonances in this process. Additionally, the studied cometary effects also significantly influence the long-term behaviour of the selected comets. LT can reach values from 100 to over 1000 years. All results indicate that the use of models with non-gravitational effects for retrograde bodies is clearly justified.
135. Observation of 10 Vesta asteroids with WISE/NEOWISE
ID:
ivo://CDS.VizieR/J/AJ/159/264
Title:
Observation of 10 Vesta asteroids with WISE/NEOWISE
Short Name:
J/AJ/159/264
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this work, we investigate the size, thermal inertia, surface roughness, and geometric albedo of 10 Vesta family asteroids using the Advanced Thermophysical Model (ATM), based on the thermal-infrared data acquired by mainly NASA's Wide-field Infrared Survey Explorer (WISE). Here, we show that the average thermal inertia and geometric albedo of the investigated Vesta family members are 42J/m^2^/s^1/2^/K and 0.314, respectively, where the derived effective diameters are less than 10km. Moreover, the family members have a relatively low roughness fraction on their surfaces. The similarity in thermal inertia and geometric albedo among the V-type Vesta family members may reveal their close connection in origin and evolution. As the fragments of the cratering event of Vesta, the family members may have undergone a similar evolutionary process, thereby leading to very close thermal properties. Finally, we estimate their regolith grain sizes with different volume filling factors.
136. Observations of the distant Kuiper belt
ID:
ivo://CDS.VizieR/J/ApJ/720/1691
Title:
Observations of the distant Kuiper belt
Short Name:
J/ApJ/720/1691
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a wide-field survey using the 1.2m Samuel Oschin Telescope at Palomar Observatory. This survey was designed to find the most distant members of the Kuiper Belt and beyond. We searched ~12000deg^2^ down to a mean limiting magnitude of 21.3 in R. A total number of 52 Kuiper Belt objects and Centaurs have been detected, 25 of which were discovered in this survey. Except for the redetection of Sedna, no additional Sedna-like bodies with perihelia greater than 45AU were detected despite sensitivity out to distances of 1000AU. We discuss the implications for a distant Sedna-like population beyond the Kuiper Belt, focusing on the constraints we can place on the embedded stellar cluster environment the early Sun may be have been born in, where the location and distribution of Sedna-like orbits sculpted by multiple stellar encounters is indicative of the birth cluster size. We also report our observed latitude distribution and implications for the size of the plutino population.
137. Observations of 50 TNOs and Centaurs
ID:
ivo://CDS.VizieR/J/A+A/584/A96
Title:
Observations of 50 TNOs and Centaurs
Short Name:
J/A+A/584/A96
Date:
21 Oct 2021
Publisher:
CDS
Description:
The prediction of stellar occultations by trans-Neptunian objects (TNOs) and Centaurs is a difficult challenge that requires accuracy both in the occulted star position and in the object ephemeris. Until now, the most used method of prediction, involving dozens of TNOs/Centaurs, has been to consider a constant offset for the right ascension and for the declination with respect to a reference ephemeris, usually the latest public version. This offset is determined as the difference between the most recent observations of the TNO/Centaur and the reference ephemeris. This method can be successfully applied when the offset remains constant with time, i.e. when the orbit is stable enough. In this case, the prediction even holds for occultations that occur several days after the last observations. This paper presents an alternative method of prediction, based on a new accurate orbit determination procedure, which uses all the available positions of the TNO from the Minor Planet Center database, as well as sets of new astrometric positions from unpublished observations. Orbits were determined through a numerical integration procedure called NIMA, in which we developed a specific weighting scheme that considers the individual precision of the observation, the number of observations performed during one night by the same observatory, and the presence of systematic errors in the positions.
138. Observed light curve of (3200) Phaethon
ID:
ivo://CDS.VizieR/J/ApJ/793/50
Title:
Observed light curve of (3200) Phaethon
Short Name:
J/ApJ/793/50
Date:
21 Oct 2021
Publisher:
CDS
Description:
(3200) Phaethon exhibits both comet- and asteroid-like properties, suggesting it could be a rare transitional object such as a dormant comet or previously volatile-rich asteroid. This justifies detailed study of (3200) Phaethon's physical properties as a better understanding of asteroid-comet transition objects can provide insight into minor body evolution. We therefore acquired time series photometry of (3200) Phaethon over 15 nights from 1994 to 2013, primarily using the Tektronix 2048x2048 pixel CCD on the University of Hawaii 2.2 m telescope. We utilized light curve inversion to (1) refine (3200) Phaethon's rotational period to P=3.6032+/-0.0008 hr; (2) estimate a rotational pole orientation of {lambda}=+85{deg}+/-13{deg} and {beta}=-20{deg}+/-10{deg}; and (3) derive a shape model. We also used our extensive light curve data set to estimate the slope parameter of (3200) Phaethon's phase curve as G~0.06, consistent with C-type asteroids. We discuss how this highly oblique pole orientation with a negative ecliptic latitude supports previous evidence for (3200) Phaethon's origin in the inner main asteroid belt as well as the potential for deeply buried volatiles fueling impulsive yet rare cometary outbursts.
139. Occultations of stars by asteroids 1995-96
ID:
ivo://CDS.VizieR/J/AJ/109/1363
Title:
Occultations of stars by asteroids 1995-96
Short Name:
J/AJ/109/1363
Date:
21 Oct 2021
Publisher:
CDS
Description:
Predictions, based on a computerized comparison of asteroid ephemerides with the catalog positions of 567,500 stars, are given for 155 occultations of stars by asteroids in 1995 and 1996. On average, the predictions are expected to be more accurate than in earlier searches because of the use of more modern star catalogs. A number of very favorable occultations, visible in North Armerica and elsewhere, are discussed.
140. Occultations of stars by large TNO 2004-2014
ID:
ivo://CDS.VizieR/J/PAZh/30/692
Title:
Occultations of stars by large TNO 2004-2014
Short Name:
J/PAZh/30/692
Date:
21 Oct 2021
Publisher:
CDS
Description:
Occultations of stars brighter than 15m by largest trans-Neptunian objects (TNOs) are predicted. Search was performed using the following catalogues: Hipparcos (Cat. <I/239>; Tycho2 (Cat. <I/259>) with coordinates of 2838666 stars taken from UCAC2 (Herald, 2003); UCAC2 (Zacharias et al., 2003, Cat. <I/289>) with 16356096 stars between 12.00 and 14.99mag to the north from -45{deg} declination. Predictions were made for 17 largest numbered transneptunian asteroids and 4 known binary Kuiper Belt objects. 67 events occuring at solar elongation of 30{deg} and more are selected. Observations of these occultations by all available means are extremely important since they can give unique information about the size of TNOs and improve their orbits dramatically. Finder charts and preliminary path plots are available separately at http://hea.iki.rssi.ru/~denis/TNOocc.html of by E-mail to denis@hea.iki.rssi.ru