[Iaude] CBET 4383: 20170417 : COMET C/2015 ER_61 (PANSTARRS)

quai at eps.harvard.edu quai at eps.harvard.edu
Mon Apr 17 11:55:14 EDT 2017


                                                  Electronic Telegram No. 4383
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET C/2015 ER_61 (PANSTARRS)
     This comet has undergone a sudden brightening in the last two weeks.
Selected visual total-magnitude and coma-diameter estimates:  Feb. 28.31 UT,
11.3, 1' (M. Goiato, Aracatuba, Brazil, 0.22-m reflector); Mar. 24.84, 8.9,
5'.5 (A. Pearce, Nedlands, W. Australia, 0.1-m reflector); 25.33, 9.5, 5'
(Goiato); 28.19, 8.7, 4' (J. J. Gonzalez, Asturias, Spain, 25x100 binoculars);
30.33, 8.5, 6' (Goiato, 20x100 binoculars); 31.84, 7.6, 10' (Pearce); Apr.
1.18, 8.2, 6' (Gonzalez, Leon, Spain); 2.28, 8.4, 6' (Goiato); 3.80, 8.3, 5'
(M. Mattiazzo, Swan Hill, Vic., Australia, 25x100 binoculars); 5.34, 6.4, 6'
(Goiato); 5.80, 6.2, 8' (Mattiazzo, 8x40 binoculars); 7.18, 6.2, 8' (Gonzalez,
10x50 binoculars); 10.34, 6.5, 12' (Goiato, 7x50 binoculars; moonlight,
clouds).  Mattiazzo notes that an ion tail at least 30' long was visible on
Apr. 5.80 in 25x100 binoculars.
     The following updated orbital elements are by S. Nakano, Sumoto, Japan,
from 849 observations spanning 2015 Jan. 21-2017 Apr. 15 (mean residual 0".53).

                    Epoch = 2017 May   7.0 TT
     T = 2017 May   9.94428 TT        Peri. =  68.19431
     e = 0.9973050                    Node  = 235.22032 2000.0
     q = 1.0421269 AU                 Incl. =   6.34889

Nakano calulates original = +0.001397 and future 1/a = +0.002331 (+/-
0.000001), adding that the comet passed 0.92 AU from Jupiter on 2016 Mar. 28
UT.  He notes that the residuals of Apr. 2017 observations were +5", mainly
in right ascension, with respect to his orbit in the ICQ's 2017 Comet
Handbook (and NK 3275).
     The following ephemeris is computed from the above orbital elements, with
the magnitude calculated as Mag. = 6.0 + 5 log Delta + 10.0 log r.

2017 TT    R. A. (2000) Decl.     Delta      r     Elong.   Mag.
Apr.  7    20 59.81   -13 58.4    1.203    1.178    63.8    7.1
     12    21 24.88   -11 37.5    1.187    1.142    62.2    6.9
     17    21 49.62   -09 07.4    1.179    1.111    60.5    6.8
     22    22 13.85   -06 31.6    1.180    1.085    58.9    6.7
     27    22 37.43   -03 53.9    1.188    1.065    57.3    6.6
May   2    23 00.23   -01 17.7    1.202    1.051    55.9    6.6
      7    23 22.21   +01 14.0    1.223    1.043    54.7    6.6
     12    23 43.31   +03 39.0    1.248    1.043    53.8    6.7
     17    00 03.54   +05 55.7    1.277    1.049    53.0    6.7
     22    00 22.90   +08 03.0    1.308    1.062    52.6    6.8
     27    00 41.37   +10 00.3    1.341    1.081    52.4    7.0
June  1    00 58.98   +11 47.5    1.375    1.106    52.5    7.1
      6    01 15.73   +13 24.7    1.409    1.136    52.9    7.3
     11    01 31.64   +14 52.3    1.443    1.171    53.5    7.5
     16    01 46.73   +16 10.7    1.475    1.210    54.4    7.7
     21    02 01.01   +17 20.5    1.506    1.253    55.5    7.9
     26    02 14.48   +18 22.3    1.535    1.299    56.9    8.1
July  1    02 27.14   +19 16.6    1.562    1.348    58.5    8.3
      6    02 39.02   +20 04.1    1.586    1.398    60.4    8.5
     11    02 50.10   +20 45.3    1.607    1.451    62.5    8.6
     16    03 00.39   +21 20.9    1.626    1.505    64.7    8.8
     21    03 09.90   +21 51.2    1.642    1.561    67.2    9.0
     26    03 18.61   +22 16.7    1.655    1.617    69.9    9.2
     31    03 26.50   +22 37.9    1.665    1.675    72.8    9.3
Aug.  5    03 33.57   +22 55.0    1.672    1.733    76.0    9.5
     10    03 39.82   +23 08.4    1.677    1.791    79.3    9.7
     15    03 45.22   +23 18.4    1.680    1.850    82.8    9.8
     20    03 49.75   +23 25.2    1.680    1.909    86.6    9.9
     25    03 53.40   +23 28.9    1.679    1.968    90.6   10.1
     30    03 56.14   +23 29.7    1.676    2.028    94.8   10.2
Sept. 4    03 57.96   +23 27.6    1.673    2.087    99.2   10.3


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2017 CBAT
2017 April 17                    (CBET 4383)              Daniel W. E. Green




More information about the Iaude mailing list