* Astronomy

Blobrana · L

RE: Asteroid (90) Antiope

Blobrana · L

Antipoe7-11_0001

This is the occultation of LQ Aquarii by the asteroid (90) Antiope. It occurred on 19 July, 2011 at 3:25 a.m. PDT.

20110719 Antiope occultation from +25km

Blobrana · L

Scottys Sky Live broadcast of Antiope asteroidal occultation expedition

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Scottys Sky 07/19/11 03:22AM

20110719 Antiope occultation from +25km

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Scottys Sky 07/18/11 09:37PM
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Scottys Sky 07/18/11 08:48PM
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Blobrana · L

The magnitude 12.5 binary asteroid (90) Antiope will occult the magnitude 6.7 variable star LQ Aquarii (HD 215553) (5.8 magnitude drop) in the constellation Aquarius, at ~10:39 UT, 19th July, 2011.
The 40 ±120 second event will be visible from western America.

Google earth file: Antiope occult.kml (936kb, kmz)

Position (2000): RA 22 46 14.22156 | Dec -11° 09' 58.6989''

Ephemeris

Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V
2011 07 18 200000 22 46 20.0 -11 08 38   1.833   2.666  136.8  15.1  12.6
2011 07 18 230000 22 46 18.8 -11 08 54   1.832   2.666  136.9  15.1  12.6
2011 07 19 020000 22 46 17.6 -11 09 10   1.831   2.666  137.1  15.0  12.5
2011 07 19 050000 22 46 16.4 -11 09 26   1.830   2.666  137.2  15.0  12.5
2011 07 19 080000 22 46 15.2 -11 09 42   1.829   2.666  137.3  15.0  12.5
2011 07 19 110000 22 46 13.9 -11 09 59   1.828   2.666  137.4  14.9  12.5
2011 07 19 140000 22 46 12.6 -11 10 15   1.827   2.666  137.6  14.9  12.5
2011 07 19 170000 22 46 11.3 -11 10 32   1.826   2.666  137.7  14.9  12.5
2011 07 19 200000 22 46 10.0 -11 10 48   1.825   2.666  137.8  14.8  12.5
2011 07 19 230000 22 46 08.7 -11 11 05   1.824   2.666  137.9  14.8  12.5
2011 07 20 000000 22 46 08.2 -11 11 11   1.823   2.666  138.0  14.8  12.5
2011 07 21 000000 22 45 56.7 -11 13 30   1.815   2.667  139.0  14.5  12.5
2011 07 22 000000 22 45 43.7 -11 15 57   1.807   2.667  140.0  14.2  12.5
2011 07 23 000000 22 45 29.2 -11 18 31   1.800   2.667  141.0  13.9  12.5
2011 07 24 000000 22 45 13.4 -11 21 13   1.792   2.668  142.1  13.5  12.4
2011 07 25 000000 22 44 56.3 -11 24 03   1.785   2.668  143.1  13.2  12.4
2011 07 26 000000 22 44 37.7 -11 26 59   1.778   2.668  144.1  12.9  12.4
2011 07 27 000000 22 44 17.7 -11 30 03   1.771   2.669  145.2  12.6  12.4
2011 07 28 000000 22 43 56.5 -11 33 13   1.764   2.669  146.2  12.2  12.4
2011 07 29 000000 22 43 33.9 -11 36 30   1.758   2.669  147.3  11.9  12.3
2011 07 30 000000 22 43 09.9 -11 39 53   1.752   2.670  148.3  11.5  12.3
2011 07 31 000000 22 42 44.7 -11 43 23   1.746   2.670  149.4  11.2  12.3
2011 08 01 000000 22 42 18.3 -11 46 58   1.740   2.670  150.5  10.8  12.3
2011 08 02 000000 22 41 50.6 -11 50 39   1.734   2.671  151.5  10.4  12.3
2011 08 03 000000 22 41 21.7 -11 54 26   1.729   2.671  152.6  10.1  12.2
2011 08 04 000000 22 40 51.6 -11 58 18   1.724   2.671  153.7   9.7  12.2
2011 08 05 000000 22 40 20.4 -12 02 14   1.719   2.672  154.8   9.3  12.2
2011 08 06 000000 22 39 48.1 -12 06 16   1.714   2.672  155.9   8.9  12.2
2011 08 07 000000 22 39 14.8 -12 10 21   1.710   2.673  157.0   8.5  12.2

Blobrana · L

Title: The Origin of (90) Antiope From Component-Resolved Near-Infrared Spectroscopy
Authors: Franck Marchis, J. Emilio Enriquez, Joshua P. Emery, Jerome Berthier, Pascal Descamp, Frederic Vachier

The origin of the similarly-sized binary asteroid (90) Antiope remains an unsolved puzzle. To constrain the origin of this unique double system, we recorded individual spectra of the components using SPIFFI, a near-infrared integral field spectrograph fed by SINFONI, an adaptive optics module available on VLT-UT4. Using our previously published orbital model, we requested telescope time when the separation of the components of (90) Antiope was larger than 0.087", to minimize the contamination between components, during the February 2009 opposition. Several multi-spectral data-cubes in J band (SNR=40) and H+K band (SNR=100) were recorded in three epochs and revealed the two components of (90) Antiope. After developing a specific photometric extraction method and running an error analysis by Monte-Carlo simulations, we successfully extracted reliable spectra of both components from 1.1 to 2.4 um taken on the night of February 21, 2009. These spectra do not display any significant absorption features due to mafic mineral, ices, or organics, and their slopes are in agreement with both components being C- or Cb- type asteroids. Their constant flux ratio indicates that both components' surface reflectances are quite similar, with a 1-sigma variation of 7%. By comparison with 2MASS J, H, K colour distribution of observed Themis family members, we conclude that both bodies were most likely formed at the same time and from the same material. The similarly-sized system could indeed be the result of the breakup of a rubble-pile proto-Antiope into two equal-sized bodies, but other scenarios of formation implying a common origin should also be considered.

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