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Photometric observations of Earth‐impacting asteroid 2008 TC 3
Author(s) -
KOZUBAL Marek J.,
GASDIA Forrest W.,
DANTOWITZ Ronald F.,
SCHEIRICH Peter,
HARRIS Alan W.
Publication year - 2011
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2011.01172.x
Subject(s) - asteroid , albedo (alchemy) , near earth object , brightness , geometric albedo , geology , astrobiology , earth (classical element) , absolute magnitude , photometry (optics) , physics , astronomy , art , stars , performance art , galaxy , art history
– A calibrated lightcurve is presented of the near‐Earth asteroid 2008 TC 3 , obtained before it impacted Earth on October 7, 2008. The asteroid was observed in unfiltered images from the end of astronomical twilight until the object entered Earth’s shadow about 2 h later. The observations covered a wide range of phase angles from 14.79° to 2.93°, during which the asteroid ranged from 82,000 km to 29,000 km distance from the observer. A method is presented for obtaining photometrically filtered brightness values for the asteroid using unfiltered imaging techniques. Over 1,700 images of the asteroid produce a lightcurve with a peak‐to‐peak variation in V of 0.76 magnitude. Analysis of the lightcurve yields values for H = 30.86 ± 0.01 and G = 0.33 ± 0.03. Combined with other constraints on the kinetic energy and diameter of the asteroid, which suggest a low 1.8 g cm −3 density and albedo 0.05 ± 0.01, the value of H implies an asteroid of about 4.1 m in diameter, 28 m 3 in volume, and 51,000 kg in mass. The determined value of G is out of range for normal, larger asteroids of albedo 0.05–0.15.