(5391)  Emmons

Prof. Richard EmmonsIt is indeed rare that a person gets a little piece of immortality by having a celestial body named after him.  It is doubly rare when it is someone we know.  Our good friend, and member of the Wilderness Center Astronomy Club, Dick Emmons, was recently accorded this honor.

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Dr. Eleanor HelinThe asteroid was discovered on September 13, 1985 by the intrepid discoverer of asteroids, Dr. Eleanor Helin as part of her Palomar Earth-Crossing Asteroid Survey.  (Dr. Helin is also the Principal Investigator for the Near Earth Asteroid Tracking program NEAT program.) A temporary designation of 1985 RE2 was given to this body.  A permanent designation cannot be given until the body has a well-determined set of orbital elements and has been observed through several oppositions.  This was done with 1985 RE2.  Also, apparently the archive of photographic plates was searched and several earlier apparitions of this body were discovered.  It also now bears the designations of 1934 RH, 1951 RF1 and 1975 VE3.  Once the orbit is well known, a name can be attached to the body.

Dr. Helin was in Cleveland a few months ago to speak at the Natural History Museum.  Dick Emmons contacted her ahead of time and told her he would like to meet her.  Dick has always been drawn to celestial objects that move – asteroids, comets, satellites and the like.  He has a passion for and a well-developed knowledge of celestial mechanics and is probably more “at home” calculating orbits and orbital elements than you and I are with balancing a checkbook.  Dick’s satellite calculations, before calculators, were legendary.

When Dick met Dr. Helin, he “talked shop” with her, and gave her a copy of the autobiographical notes he had prepared for the presentation to the WCAC and the GLPA meeting in Cleveland a couple years ago.  In those notes, he told the story of how an article he saw about the recently (at the time) discovered asteroid (1862) Apollo – the prototype of a group of Earth-crossing asteroids, fueled his interest in astronomy.

Well, Dr. Helin has discovered a basket-full of asteroids, and she decided to propose that one of them be named for Dick Emmons.

Here is the citation, from a letter dated 8 June, 2000:

“MPC (Minor Planet Circular) 40701.  5391 Emmons = 1985 RE2.
Discovered 1985 September 13 by E.F. Helin at Palomar.
Richard Emmons (b. 1919), Emeritus Professor of Physics at Ohio’s
Kent State University had his interest in astronomy sparked by an article
published soon after the discovery of 1932 HA (now 1862) Apollo.
He was an early observer of artificial satellites.”

Now, of course Dick has played with this rocky namesake of his. Or as he calls it "Since this is asteroid number 5391, we could jokingly call it the Five Thousand Three Hundred Ninety-first Rock From The Sun. It's a mountain on the loose, about 10 miles across!". He has taken the orbital elements and calculated that 5391 Emmons has a perihelion (minimum distance to the sun) of 159 million miles, and an aphelion (maximum distance) of 261 million miles.  This keeps it outside the orbit of Mars (156.7 million miles at aphelion).  He has also calculated that in late August or early September of 2002, his namesake will be about as close as it gets to Earth. The closest possible opposition is about 65 million miles, and in 2002 it will be 68 million miles away.  That will bring its brightness up from the mid-18th magnitude range where it currently resides to about 14.0 magnitude – putting it within visual range of our telescopes.  I have already invited Dick to join us at the eyepiece of the Keller Telescope to try and see his eponymous rock.  It will be about as bright as Pluto – a challenge, but certainly doable.

Dick has also played with the elements and precessed them back to 1855 (!) so that he could plot them on the Bonner Durchmusterung star atlas!  In the 2002 opposition, 5391 Emmons will be in Aquarius, near the Pisces border, moving retrograde at about 30 arcseconds per hour.  I have plotted the path using MEGASTAR and a couple plots are linked below.

emmonsplot.jpg (56K jpeg)

emmonsplot.doc (41K) Word document suitable for printing.

Below is an ephemeris plotted for the next couple of years at 45 day intervals from the Minor Planet Center’s Ephemeris Service web site:

(5391) Emmons

Epoch 2000 Sept. 13.0 TT = JDT 2451800.5 (M-c)          Nakano
M 164.73043              (2000.0)                  P                        Q
n   0.29023699     Peri.  344.27356     +0.77566429     +0.63090477
a   2.2592669      Node 336.58232      -0.57423158     +0.69398302
e   0.2429835      Incl.    2.51470         -0.26192174     +0.34691027
P   3.40                H   13.2                 G   0.15
From 36 observations at 5 oppositions, 1950-2000.

Last observed on 2000 Mar. 4. Elements from MPC 21243.

05391
Date         TT    R.A.        Decl.        Delta    r         El.      Ph.    V       Motion
                                                                                                                 "/min   P.A.
2000 07 01 00   07 38.30  +22 42.3    3.716  2.736    13.1    4.8  18.6     0.99   100.3
2000 08 15 00   08 52.09  +18 34.3    3.760  2.778    12.2    4.4  18.7     0.97   106.4
2000 09 29 00   09 58.64  +13 10.1    3.509  2.802    39.0   13.0  18.9    0.89   110.7
2000 11 13 00   10 53.14  +07 43.9    3.001  2.808    69.3   19.2  18.8    0.69   113.4
2000 12 28 00   11 25.08  +04 06.1    2.357  2.795  106.2   19.7  18.3    0.23   118.1
2001 02 11 00   11 14.92  +04 40.3    1.841  2.764  154.5    8.8   17.3    0.51   289.3
2001 03 28 00   10 33.02  +08 21.0    1.808  2.715  149.4   10.8  17.3    0.49   288.7
2001 05 12 00   10 24.96  +08 48.6    2.225  2.648  103.4   21.8  18.1    0.26   113.7
2001 06 26 00   11 00.04  +05 08.4    2.733  2.565    69.8   21.8  18.5    0.74   113.1
2001 08 10 00   11 58.27   -01 12.0    3.114  2.466    42.7   16.2  18.5    1.00   113.8
2001 09 24 00   13 10.16   -08 57.3    3.282  2.353    18.6     7.8  18.2    1.16   112.7
2001 11 08 00   14 34.39   -16 46.2    3.217  2.230     4.4      1.9  17.7    1.27   108.6
2001 12 23 00   16 12.19   -22 54.5    2.942  2.102    25.9   11.8  17.9    1.36   100.9
2002 02 06 00   18 01.74   -25 24.6    2.518  1.976    46.6   21.3  17.7    1.42   090.3
2002 03 23 00   19 54.08   -23 03.7    2.026  1.861    66.1   29.3  17.4    1.42   079.4
2002 05 07 00   21 36.69   -16 35.0    1.542  1.771    85.2   34.6  16.8    1.32   070.9
2002 06 21 00   22 56.94   -08 44.4    1.117  1.719   107.3  34.4  16.0    0.95   065.2
2002 08 05 00   23 31.29   -03 47.4    0.806  1.714   140.5  22.1  15.0    0.11   355.9
2002 09 19 00   23 03.66   -04 25.2    0.761  1.758   169.4    6.1  14.3    0.47   259.6
2002 11 03 00   23 01.16   -03 38.8    1.087  1.841   124.7  26.3  15.9    0.46   065.6
2002 12 18 00   23 53.03  +01 51.6    1.631  1.952    93.3   30.2  17.0    1.01   067.2

Dick has been an astronomy educator most of his life.  Many of us have heard the stories of some of his earlier exploits – the star watches when a student at Kent State, his home-brewed planetarium projectors, the thousands of students who passed through his North Canton planetarium behind his home on Donner Street, his passionate involvement in tracking satellites in the early days of the program, his research project on Echo 1 and the interplanetary medium, his satellite tracking at Palomar, and many other stories.  We did not get to meet Dick until after he retired from his teaching career at Kent State.  So our primary exposure to Dick has been as a fellow amateur astronomer.  Those of us who have watched him have been impressed with his professionalism as an amateur.  Through my involvement in occultation timing work, I have received several of Dick’s reports.  They are precise with an impressive attention to detail.  He still has a well-trained observing eye and can observe circles around most of us.  He also still keeps a close eye on artificial satellites – we get notes from Dick from time to time about interesting geostationary satellites and others.  Of particular interest has been his “tether” satellite which we have seen occasionally.

Most of us also know Dick as the father of the recently-retired planetarium projector from TWC’s Interpretive Building.  It gave us 15 years of fine service.  His daughter and son, Jeanne and Tom have been speakers for us over the years as well.

So, Dick, as your friends we want to congratulate you on this singular honor! And you can bet that we’ll point the Keller Telescope toward 5391 Emmons when it brightens in 2002. It is our sincerest hope that you will be able to join us at the eyepiece.

Dave Gill
July 8, 2000
 


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