Full moon is on February 8 (NZDT) so there will be considerable moonlight at the time Eros is brightest. However Eros is always some distance from the moon so the asteroid is likely to be visible in binoculars.
Eros first brightens to magnitude 9.5 on December 29 as it moves from Leo Minor into Leo. It will then be well north of the celestial equator and low in New Zealand skies. Over the next few weeks during the period near opposition, Eros will be moving to the south as seen from the Earth, rather than the more normal west. After being in Leo, Eros will move into Sextans on January 20 and then cross Hydra during February. It will move into Antlia at the beginning of March as its magnitude drops back to 9.5.
The southerly motion will bring it higher into southern hemisphere skies. It is just south of the equator when brightest at the beginning of February. The north to south motion is similar to that of (1036) Ganymed, the largest NEA, which was at opposition at the end of October 2011 and brightened to magnitude 8.3.
The previous best determinations of the Sun's distance had been made by observations of the transit of Venus in the 18th and 19th centuries. So it seems appropriate that Eros should make another close approach in 2012 with another transit of Venus also occurring in June. The determinations of the Sun's distance using Eros remained the most accurate until radar measures later in the 20th century.
Eros was visited by the NASA spacecraft NEAR Shoemaker in 2000 when the elongated shape of the asteroid was imaged. In 2001 it descended to the surface. Eros is roughly cylindrical with dimensions about 34km x 11km x 11 km.
Eros's orbital period is 1.761 years, just over 643 days. Its distance from the Sun varies from 1.134 to 1.78 AU with a mean distance 1.46 AU. Thus at aphelion it is beyond the orbit of Mars. The eccentricity of the orbit is 0.223 and its inclination to the ecliptic is 10.8°.
Favourable oppositions of Eros always occur close to the end of January. At that time the Earth is 0.985 AU from the Sun. At the closest oppositions Eros is 0.149 AU from the Earth. The last close opposition of Eros was 1975 January 23 with at a distance of 0.151 AU, the next is 2056 January 24 at 0.150 AU. The close oppositions occur alternately at intervals of 37 and 44 years.
Path of Eros 2011 to 2012
Eros, moving south, crosses from Leo Minor to Leo at the end of December 2011. It brightens to
magnitude 9.5 on December 29 and to 9.0 b January 11.
Eros is about 3.8° from ζLeo, magnitude 3.42, on January 2
and 4° from γLeo, magnitude 2.23, on January 6.
Path of Eros 2012
Eros moves from Leo into Sextans on January 21. By then it will be at magnitude 8.7.
Eros is about 8° from Regulus, αLeo, magnitude 1.41, on January 15.
Path of Eros 2012
Eros is at its brightest during the period covered by this chart. It crosses into Hydra
from Sextans on February 6 when it will be at magnitude 8.55.
Eros is about 1.6° from βSex, magnitude 5.06, on January 27. and 3° from λHya, magnitude 3.60, on February 8
Path of Eros 2012
Eros crosses Hydra during February and moves into Antlia early March.
By then its motion through the stars will have slowed. It fades from magnitude 8.6 on February
10 to 9.5 by March 11. The chart also shows the path of Eros during the rest of March as it
loops and starts moving back to the east. On March 31 its magnitude will be 10.3
Eros is about 2° from μHya, magnitude 3.8, on February 11 and 12.
On March 11, when at magnitude 9.5, Eros will be only 5.5' from θAnt, magnitude 4.79
|2011 Dec 22||10 15.4||+32 22||9.8||0.263||1.151||Leo Minor|
|2011 Dec 27||10 24.3||+29 01||9.8||0.245||1.145||Leo Minor|
|Jan 1||10 31.4||+25 13||9.4||0.229||1.140||Leo|
|Jan 6||10 36.6||+20 57||9.2||0.214||1.137||Leo|
|Jan 11||10 39.8||+16 13||9.0||0.202||1.135||Leo|
|Jan 16||10 41.1||+11 06||8.9||0.202||1.135||Leo|
|Jan 21||10 40.2||+05 41||8.7||0.185||1.134||Sextans|
|Jan 26||10 37.4||+00 08||8.6||0.180||1.136||Sextans|
|Jan 31||10 32.8||-05 20||8.6||0.179||1.138||Sextans|
|Feb 5||10 26.8||-10 28||8.6||0.180||1.143||Sextans|
|Feb 10||10 19.7||-15 04||8.6||0.185||1.148||Hydra|
|Feb 15||10 12.2||-18 59||8.7||0.192||1.154||Hydra|
|Feb 20||10 04.6||-22 08||8.8||0.201||1.162||Hydra|
|Feb 25||09 57.6||-24 30||9.0||0.212||1.171||Hydra|
|Mar 1||09 51.6||-26 11||9.2||0.226||1.180||Hydra|
|Mar 6||09 47.2||-27 16||9.4||0.241||1.191||Antlia|
|Mar 11||09 44.3||-27 52||9.5||0.257||1.202||Antlia|
|Mar 16||09 43.1||-28 03||9.7||0.276||1.214||Antlia|
|Mar 21||09 43.5||+27 56||9.9||0.295||1.227||Antlia|
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