The changing rotational lightcurve of Varuna and evidence for a close-in satelite

From CCD observations carried out with different telescopes, we present short-term photometric measurements of the large trans-Neptunian object Varuna in 10 epochs, spanning around 19 years.

We observe that the amplitude of the rotational light curve has changed considerably during this period of time from 0.41 to 0.55 mag… We propose that these changes in the rotational light-curve shape are due to a large and close-in satellite whose rotation induces the additional periodicity. The peak-to-valley amplitude of this oscillation is in the order of 0.04 mag. We estimate that the satellite orbits Varuna with a period of 11.9819 hr (or 23.9638 hr).

The Astrophysical Journal Letters, 883:L21 (7pp), 2019 September 20 © 2019. The American Astronomical Society.

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Binary asteroid IAU announcement telegram

(2019) VAN ALBADA
V. Benishek, Belgrade Astronomical Observatory; P. Pravec, Ondrejov
Observatory; R. Durkee, Shed of Science South Observatory, Pontotoc, TX,
U.S.A.; M. Husarik, M. Pikler, G, Cervak, and D. Tomko, Skalnate Pleso
Observatory; B. Christmann, Soucieu-en-Jarrest, France; A. Aznar, Isaac
Aznar Observatory, Alcublas, Valencia, Spain; D. Pray, Sugarloaf Mountain
Observatory, South Deerfield, MA, U.S.A.; F. Pilcher, Organ Mesa Observatory,
Las Cruces, NM, U.S.A.; V. Chiorny, Kharkiv Observatory; and A. Marchini, R..
Papini, and F. Salvaggio, Dipartimento di Scienze Fisiche, Della Terra e
Dell’Ambiente, University of Siena, report that photometric observations
taken with a 0.35-m telescope at the Sopot Observatory in Serbia, a 0.50-m
telescope at the Shed of Science South Observatory, a 0.61-m telescope at
the Skalnate Pleso Observatory, 0.28-m telescope at Soucieu-en-Jarrest, a
0.35-m telescope at the Isaac Aznar Observatory, a 0.50-m telescope at the
Sugarloaf Mountain Observatory, a 0.35-m telescope at the Organ Mesa
Observatory, a 0.70-m telescope at the Chuguev station of the Kharkiv
Observatory in Ukraine, and a 0.30-m telescope at the Astronomical
Observatory of the University of Siena during Sept. 22-Oct. 26 reveal that
minor planet (2019) is a binary system with an orbital period of 17.982 ±
0.003 hr. The primary shows a period of 2.7294 ± 0.0005 hr and has a
lightcurve amplitude of 0.16 magnitude at solar phases 2-3 degrees. Mutual
eclipse/occultation events that are 0.07 to 0.12 magnitude deep indicate a
lower limit on the secondary-to-primary mean-diameter ratio of 0.26.

2019 October 30 (CBET 4689) Daniel W. E. Green

Binary asteroid IAU announcement telegram

(18303) 1980 PU
V. Benishek, Belgrade Astronomical Observatory; P. Pravec and P.
Kusnirak, Ondrejov Observatory; R. Durkee, Shed of Science South Observatory,
Pontotoc, TX, U.S.A.; D. Pray, Sugarloaf Mountain Observatory, South
Deerfield, MA, U.S.A.; V. Chiorny and O. Mikhalchenko, Kharkiv Observatory;
M. Husarik and M. Pikler, Skalnate Pleso Observatory; J. Oey, Blue Mountains
Observatory, Leura, NSW, Australia; P. Bacci and M. Maestripieri,
Astronomical Observatory, San Marcello Pistoiese, Italy; and A. Aznar, Isaac
Aznar Observatory, Alcublas, Valencia, Spain, report that photometric
observations taken with a 0.35-m telescope at the Sopot Observatory in
Serbia, a 0.50-m telescope at the Shed of Science South Observatory, a
0.50-m telescope at the Sugarloaf Mountain Observatory, a 0.70-m telescope
at the Chuguev station of the Kharkiv Observatory in Ukraine, a 0.61-m
telescope at the Skalnate Pleso Observatory, a 0.35-m telescope at the Blue
Mountains Observatory, a 0.60-m telescope at the San Marcello Pistoiese
Observatory, and a 0.35-m telescope at the Isaac Aznar Observatory during
Aug. 10-Oct. 2 reveal that minor planet (18303) is a binary system with an
orbital period of 12.270 ± 0.003 hr. The primary shows a period of
2.72627 ± 0.00010 hr and has a lightcurve amplitude of 0.10 magnitude at
solar phases 4-14 degrees, suggesting a nearly spheroidal shape. Mutual
eclipse/occultation events that are 0.05 to 0.12 magnitude deep indicate
a secondary-to-primary mean-diameter ratio of 0.24 ± 0.03.

2019 October 9 (CBET 4676) Daniel W. E. Green» [2019-10-10 07:45, Ondrejov]

(416032) 2002 EX11

Number: 416032
Designation: 2002 EX11
Name:  –
First Date: 2015/03/14
Points: 115
P1: 5.36
P1 error: 0.01
Max. Ampl.: 0.66

 

Optical Ground Station Telescope

Observatorio del Teide

EURONEAR

(285331) 1999 FN53

Number: 285331
Designation: 1999 FN53
Name:  –
First Date: 2015/04/21
Points: 393
P1: 4.42
P1 error: 0.01
Max. Ampl.: 1.07

 

IAC80 telescope

Observatorio del Teide, IAC

EURONEAR

(624) Hektor

Number: 624
Designation:-
Name:  Hektor
First Date: 2019/08/28
Points: 224
P1: 6.924
P1 error: 0.001
Max. Ampl.: 0.16

 

 

First Date: 2019/09/05
Points: 80
P1: 6.92
P1 error: 0.01
Max. Ampl.: 0.14

 

 

 

Hektor star occultation: 2019/08/28

Troyan asteroid

(293054) 2006 WO127

Number: 293054
Designation: 2006 WP127
Name:  –
First Date: 2019/07/19
Points: 398
P1: 5.9659
P1 error: 0.0001
Max. Ampl.: 0.25

 

Lightcurve from Isaac Aznar Observatory  and TAR2 telescope (IAC-Solar System Group).

(455432) 2003 RP8

Number: 455432
Designation: 2003 RP8
Name:  –
First Date: 2019/07/27
Points: 228
P1: 2.289
P1 error: 0.004
Max. Ampl.: 0.42

 

Lightcurve from POP Observatory and TAR2 telescope (IAC-Solar System Group).

(12538) 1998 OH

Number: 12538
Designation: 1998 OH
Name:  –
First Date: 2019/07/10
Points: 81
P1: 2.58
P1 error: 0.01
Max. Ampl.: 0.15

 

Lightcurve from TAR2 telescope (IAC-Solar System Group) and APT-Observatories Group.

(453778) 2011 JK

Number: 453778
Designation: 2011 JK
Name:  –
First Date: 2019/06/07
Points: 158
P1: 2.578
P1 error: 0.003
Max. Ampl.: 0.14

 

Lightcurve from Isaac Aznar Observatory and TAR2 telescope (IAC, Solar System Group).

(355256) 2007 KN4

Number: 355256
Designation: 2007 KN4
Name:  –
First Date: 2019/04/27
Points: 516
P1: 7.142
P1 error: 0.001
Max. Ampl.: 0.35

 

Lightcurve from Isaac Aznar Observatory and TAR2 telescope (IAC, Solar System Group).

Asteroid pairs: a complex picture

 

In the main belt of asteroids, there exist pairs of asteroids that are on highly similar heliocentric orbits. They were discovered by Vokrouhlický and Nesvorný (2008) who showed that the asteroid pairs cannot be random coincidences of unrelated asteroids from the local asteroid population, but most of them must be genetically related pairs.

Being motivated by the progress in our knowledge and understanding of asteroid pairs, we underwent a thorough photometric study of a sample of nearly 100 asteroid pairs.

http://aptog.com/wp-content/uploads/2019/07/astpairscomplex_Icarus_333_pp429_463.pdf