2009年6月16日，由中科大研究生浙江的杨睿用XWASS-CSP系统图片发现，后被命名为C/2009 L2(Yang-Gao)
http://www.cfa.harvard.edu/mpec/K09/K09M05.html
http://www.astronomy.com.cn/bbs/thread-113291-1-3.html
Electronic Telegram No. 4111
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
COMET P/2015 J4 = P/2009 L2 (YANG-GAO)
- Sato, Tokyo, Japan, reports his recovery of comet P/2009 L2 (cf. IAUC
9052) on CCD images obtained with an 0.51-m f/6.8 astrograph (+ luminance
filter) at Siding Spring. The comet appeared stellar on May 11 in ten stacked
60-s exposures; the w-band magnitude tabulated below for that date was
measured within a circular aperture of radius 6″.6. The comet appeared
cometary on June 9, with a faint outer coma 15″ in diameter and a fan-like
tail 30″ long spanning p.a. 45-135 degrees in eight stacked 60-s exposures;
the tabulated magnitude for June 9 were measured within a circular aperture
of radius 8″.8. Eight stacked 60-s follow-up exposures by Sato on June 10.36
UT show the comet to be moderately condensed with a faint coma 12″ in
diameter and a fan-like tail 20″ long spanning 40-130 degrees; he measured
magnitude 18.3 within a circular aperture of radius 6″.6.
2015 UT R.A. (2000) Decl. Mag. Observer
May 11.38368 9 21 24.94 – 6 48 01.6 Sato
11.38579 9 21 25.07 – 6 48 00.8 “
11.38790 9 21 25.23 – 6 48 00.2 19.1 “
June 9.37566 10 12 16.84 – 6 25 38.3 “
9.37736 10 12 17.04 – 6 25 38.3 “
9.37905 10 12 17.25 – 6 25 38.9 18.6 “
The indicated correction to the prediction by B. G. Marsden on MPC 79350 is
Delta(T) = +0.10 day.
The following linked orbital elements by G. V. Williams are from 1052
observations spanning 2009 June 15-2015 June 9 (mean residual 0″.5).
Additional elements and an ephemeris appear on MPEC 2015-L28.
Epoch = 2015 Aug. 6.0 TT
T = 2015 Aug. 15.13638 TT Peri. = 343.56508
e = 0.5936996 Node = 257.62554 2000.0
q = 1.4310835 AU Incl. = 16.69224
a = 3.5222304 AU n = 0.14909993 P = 6.61 years
NOTE: These ‘Central Bureau Electronic Telegrams’ are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2015 CBAT
2015 June 10 (CBET 4111) Daniel W. E. Green