Professor Comet Report

June 2010

Current status of the predominant comets for 2010

Comets Designation Orbital Magnitude Trend Observation Visibility (IAU(IAU(IAU-(IAU --- Status (Visual) (Lat.) Period MPC) McNaught 2009 R1 C 5 Bright 50° N - 5°N All Night McNaught 2009 K5 C 9 Fading 50°N - 20°N All night Tempel 2 10P PPP 10 Bright 50°N - 75°S Early Morning Wolf ––– 43P43P43P PPP ~111111 Bright Conjunction N/AN/AN/A Harrington Wild 2 81P PPP 11.5 Fading 50°N – 75°S Evening Christensen 2006 W3 C 12 Fading 20°N – 90°S All Night Gunn 65P PPP 12.5 Steady 40°N – 90°S Best Morning Schwassman 29P PPP ~13 Varies 25°N – 40°S Early –Wachmann Evening Vales 2010 H2 PPP 13 Possibly 50°N – 60°S Early Fading Evening

Siding Spring 2007 Q3 C 13.5 Fading 50°N - 0°S All Night Machholz 2 141P PPP ~14 Fading Conjunction N/A

The red designation is assigned to all comets that are of 12 th visual magnitude or brighter and are classified as the major comets . All remaining comets that are possibility at 12 th visual magnitude or fainter are given the blue designation and are classified as the minor comets! The green designation is assigned to comets to far south to be seen in the continental United States. The orange designation is for comets 12 th visual magnitude or brighter lost in the daytime glare!

1 C/2009 R1 (McN(McNaught)aught)

This comet is now becoming very bright and visible in the early morning hours before sunrise with visual magnitude reports indicating that this comet is now at 5 th magnitude. The comet will continue to brighten rapidly and quite possibly reach a visual magnitude of 4.7 by early July in accordance with the predictions set forth by the MPC. However, recent analysis of the photometry data obtained from the brightness of McNaught R1 show the comet reaching 2 nd or 3 rd visual magnitude during the time period of 30 June thru 2 July. The comet has been reported even from one early visual sighting from the George Observatory as a bright, glowing, greenish – blue coma. Most visual reports have given estimations for the coma size to be between 5 – 10 arcminutes with one report indicating a photographic 12 arcminute size for the coma. There are two tails extending out from the Coma in a ‘V – shaped’ pattern with a shorter dust tail extending out with an arclength equal to the coma and a long, skinny ion tail extending 5° from the Coma! The ion tail was first reported back on 6 June and the dust tail was first identified on 13 June; it has been referred to as ‘an apple on a stick’!

This is the 51 st comet to be discovered by the British-Australian astronomer Robert H McNaught on 9 September 2009 using the Uppsala Schmidt telescope at the Siding Spring observatory in Australia. This is a non periodic comet that is expected to leave the solar system permanently, so get out and observe the comet while it is still possible. Currently the comet is in the northern region of which rises in the morning sky about a couple of hours before dawn. As of 23 June the comet was about 11m 41s of RA to the West and just less than 1.25° to the North of Menkalinan ( β Aurigae) which neighbors to the East of Capella. This places the comet at a distance of 1.1791 AU from Earth and a solar distance of 0.4688 AU, but the solar elongation is now at 23°. The comet will graze by Menkalinan to its North by 0.49° during the early afternoon of 24 June. Previously the comet did fly through Perseus grazing to the southeast of the open cluster NGC 1245 during the period of 12 – 13 June. The comet is now poised to fly to the Eastern region of and fly just south of another open NGC 2218. This comet should become visible around 3 am in the morning CDT of 29 June about 45s of RA to the East and 42’ 38” of Dec. to the South of the cluster. However, the solar elongation will have been reduced to 18°.

2 The comets perigee will be increasing with the distance at 1.2492 AU the early morning CDT of 29 June while the solar distance decreases to 0.4150 AU. The comet is expected to reach its perihelion on 2 June at a solar distance predicted to be a mere 0.405 AU just placing it outside of Mercury’s . McNaught R1 will have obtained a solar elongation of less than 14° making it impossible to see in the later morning hours around sunset. During this period the comet will continue to move in a SE direction across the morning sky in the northern region of ‘The Winter Hexagon’ and cross into the northern boundary of the of Gemini the early evening of 2 July when the comet will be predominantly lost in the morning glare. The comet will afterwards be in Gemini with the for the month of July occulting Castor between 9 – 10 PM CST on 4 July after approaching perihelion. McNaught will be in Cancer from 8 – 23 July crossing into Eastern fish of with a solar elongation of 15° with the Sun in Cancer. For the foreseeable future the comet will be placed in Pisces moving southeasterly until crossing into Antlia on the last of August by then the comet will have faded to 11 th magnitude!

IAU MPC Ephemeris data for C/2009 R1: Date TT RA(2000) Decl. Delta r Elong. Phase m1 m2 2010 06 23 05 37.00 +46 44.8 1.171 0.480 24.0 59.6 5.2 2010 06 28 06 36.84 +42 00.7 1.231 0.424 18.8 50.7 4.7 2010 07 03 07 20.69 +35 08.7 1.305 0.405 14.2 37.9 4.7 2010 07 08 07 50.73 +27 30.3 1.382 0.430 10.9 26.7 5.0 2010 07 13 08 11.73 +20 04.7 1.454 0.489 10.3 21.9 5.7 2010 07 18 08 27.57 +13 16.4 1.521 0.570 12.2 22.1 6.5 2010 07 23 08 40.53 +07 08.3 1.584 0.660 15.2 23.8 7.2 2010 07 28 08 51.84 +01 35.8 1.646 0.754 18.4 25.2 7.9 2010 08 02 09 02.13 -03 26.9 1.707 0.850 21.6 26.1 8.5 2010 08 07 09 11.78 -08 05.0 1.767 0.945 24.7 26.6 9.0 2010 08 12 09 20.99 -12 22.8 1.826 1.039 27.5 26.8 9.5 2010 08 17 09 29.89 -16 23.6 1.886 1.131 30.2 26.7 9.9 2010 08 22 09 38.56 -20 10.3 1.945 1.222 32.7 26.5 10.3 2010 08 27 09 47.08 -23 44.8 2.004 1.311 35.0 26.2 10.7 2010 09 01 09 55.47 -27 09.0 2.063 1.399 37.2 25.9 11.0

3 Note: See ephemeris data terminology below .

Date: Month and using the standard Gregorian calendar.

TT: Terrestrial Time (Day of the Month) as a substitute for the astronomical Julian date.

RA(2000): based on the J2000 (longitudinal coordinate for the celestial sky) measured in hours and minutes.

Decl.: as measured in degrees and arcminutes.

Delta: The distance from Earth measured in AUs (1 AU = 1 = 92 955 807 mi = 149 597 871 km as the mean distance between the Earth and Sun).

R: The solar distance as measured in AUs.

Elong: Solar elongation which is the angle of separation between the observed object and the Sun as measured across the night sky as measured in degrees.

Phase: Phase angle between the Sun, the celestial object, and the observer on the surface of the Earth. Also known as the Sun – Object – Observer angle. m1: The visual magnitude of the celestial object as observed on the surface of the Earth at sea level. m2: The nuclear magnitude which is the visual magnitude of the false nucleus within the coma as seen by an observer here on Earth at sea level.

4 C/2009 K5 (McNaught)

This is another of McNaught comet with the latest reports showing a decent smudge with a reported visual magnitude of 8.3, so it is visible in binoculars. In photographs it shows a ghostly, mostly turquoise-like color with a faint tail only visible in exposure images. It will continue to be visible in the Northern hemisphere for quite a long time until it will eventually fade out visually around autumn and being quite low in the sky for the month of July.

K5 McNaught as of 23 June is moving through an inauspicious area of the eastern region of Camelopardalis heading east towards the bright, irregular spiral NGC 2403 which has a visual magnitude of 8.5. This galaxy is a member of the Messier 81 group which overlaps into Ursa Major; home of the big dipper asterism. The comet will be positioned about 11m 8s of RA to the West and 1.18° to the South of NGC 2403 during the favorable evening hours on 28 June. It will have by then a distance from Earth of 2.2583 AU and a solar distance of 1.6533 AU with a solar elongation of 42° McNaught then will curve southwards towards the constellation of Lynx. It will cross the constellation boundary between Camelopardalis and Lynx the early afternoon CDT on 13 July moving into Lynx. However the comet is dimming and is expected to have a visual magnitude of 11.3 thru mid July. K5 will be halfway in its journey towards 27 Lyncis close to 1 am CDT the night of 2 August, but dimming towards visual magnitude of 12.5. It is moving away from both the Earth and Sun with the prospect of leaving the Solar system indefinitely. By the time it reaches the area of Lynx around 27 Lyncis about 6m 35.5s RA to the East of that star the early afternoon CDT of 8 September. The distance from Earth will have reached 2.6642 AU with a solar distance of 2.2970 AU and a solar elongation of 58° while dimming to a visual magnitude of 13.2.

IAU MPC Ephemeris data for C/2009 K5: Date TT RA(2000) Decl. Delta r Elong. Phase m1 m2 2010 06 28 07 25.39 +64 29.9 2.255 1.652 42.3 24.5 11.4 2010 07 03 07 32.63 +62 49.2 2.325 1.688 40.6 23.1 11.6 2010 07 08 07 38.95 +61 18.1 2.390 1.726 39.2 21.8 11.8 2010 07 13 07 44.56 +59 55.6 2.449 1.765 38.1 20.8 11.9 2010 07 18 07 49.58 +58 40.9 2.502 1.806 37.6 20.1 12.1 2010 07 23 07 54.08 +57 33.3 2.549 1.849 37.5 19.5 12.2 2010 07 28 07 58.13 +56 32.2 2.588 1.892 37.9 19.2 12.3 2010 08 02 08 01.75 +55 37.2 2.622 1.937 38.7 19.1 12.5 2010 08 07 08 04.97 +54 47.8 2.648 1.983 40.1 19.2 12.6 2010 08 12 08 07.78 +54 03.7 2.668 2.029 41.8 19.5 12.7 2010 08 17 08 10.17 +53 24.7 2.681 2.076 44.0 19.8 12.8 2010 08 22 08 12.12 +52 50.5 2.688 2.124 46.6 20.2 12.9 2010 08 27 08 13.60 +52 21.0 2.689 2.172 49.4 20.7 13.0 2010 09 01 08 14.59 +51 56.0 2.684 2.221 52.6 21.2 13.1 2010 09 06 08 15.04 +51 35.3 2.673 2.270 56.1 21.6 13.2

5 10P/Tempel 2

Tempel 2 is already visible in the night skies of the northern hemisphere and it is rapidly getting brighter in the morning hours before dawn. Right now the comet has a current visual magnitude of 10.3, but it could reach a visual magnitude of 9.0 before the end of June or during the first week of July. The original prediction data from the MPC predicts a maximum visual magnitude of brightness 8.1 during the time period 13 – 28 July. It will be approaching the Sun with a solar distance of 0.674 AU expected by 2 August and Tempel 2 should reach perigee during the time period 3 – 8 July at a distance of 1.423 AU. The comet is currently located as of 23 June in Aquarius about 8m 39.5s RA to the East and 0.9° North of Chi (χ) Aquarii which is a (M3III) star with a visual magnitude of 5.06. The star is located about halfway between Phi ( Φ) Aquarii and the Psi ( ψ) Aqaurii triangle. The ‘Psi Aqaurii triangle’ is an asterism of three Psi 1, Psi 2, and Psi 3 Aqaurii which have visual magnitudes of 4.21, 4.39, and 4.98 respectfully. The comet will have a distance from Earth of 0.8031 AU, solar distance of 1.4275 AU, and a solar elongation of 103°.

Tempel 2 will continue to move eastward across the constellation boundary between Aquarius and the early morning of 4 July with the only bright star 30 Piscium at visual magnitude 4.41. This star has a spectral type of M3III and the comet will be located ~1.77° to the SW of 30 Piscium. The comet move nearly 1° to the south of 30 Piscium the early morning of 6 July. Next to 30 Piscium is the star 33 Piscium which is a special K0III type star at a visual magnitude of 4.61. Expect the comet to move ~1 1/3° to the south of 33 Piscium during the early morning hours of 7 July. 10P/Tempel 2 will move into the constellation region of Cetus heading due East and can be located about 1.5° of Iota ( ι) Ceti also known as Deneb Kaitos Shemali with a spectral classification of K1.5III at a visual magnitude of 3.56. This will happen in the mid afternoon CDT of 12 July when the comet has a distance from Earth of 0.7251 AU and a solar distance of 1.4252 AU with a solar elongation of 109°.

The comet will move eastward across the western region of Cetus reaching Eta ( η) Ceti known as Deneb Algenubi which is a bright, orange with a visual magnitude of 3.45 midnight EDT on 3 August. Tempel 2 will then progressively move ESE towards central Cetus and then progress in a more southerly direction by early September and will stay in Cetus undergoing retrograde motion for most of the remaining year. Tempel 2 will

6 by then be just slightly North of Theta Ceti on 20 December and then move rapidly to the North while not leaving the constellation until mid Spring of 2011!

IAU MPC Ephemeris data for 10P/Tempel 2: Date TT RA(2000) Decl. Delta r Elong. Phase m1 m2 2010 06 23 23 22.94 -06 50.2 0.807 1.428 102.5 44.0 8.4 16.5 2010 06 28 23 37.63 -06 48.5 0.784 1.425 103.9 43.8 8.3 16.4 2010 07 03 23 51.97 -06 52.5 0.762 1.423 105.3 43.6 8.2 16.4 2010 07 08 00 05.84 -07 02.8 0.742 1.423 107.0 43.1 8.2 16.3 2010 07 13 00 19.14 -07 19.8 0.725 1.425 108.7 42.5 8.1 16.2 2010 07 18 00 31.76 -07 43.5 0.709 1.429 110.6 41.7 8.1 16.2 2010 07 23 00 43.59 -08 14.0 0.696 1.435 112.7 40.8 8.1 16.1 2010 07 28 00 54.54 -08 51.2 0.684 1.443 114.9 39.6 8.2 16.0 2010 08 02 01 04.50 -09 34.8 0.674 1.453 117.3 38.3 8.2 16.0 2010 08 07 01 13.35 -10 24.4 0.665 1.465 120.0 36.9 8.3 15.9 2010 08 12 01 21.02 -11 19.4 0.659 1.478 122.8 35.2 8.3 15.9 2010 08 17 01 27.41 -12 18.7 0.654 1.493 125.8 33.4 8.4 15.8 2010 08 22 01 32.49 -13 21.0 0.651 1.509 129.0 31.4 8.5 15.8 2010 08 27 01 36.22 -14 25.0 0.651 1.527 132.4 29.3 8.7 15.8 2010 09 01 01 38.61 -15 28.9 0.653 1.546 135.8 27.1 8.8 15.7 2010 09 06 01 39.66 -16 31.0 0.658 1.567 139.3 24.8 9.0 15.7 2010 09 11 01 39.45 -17 29.0 0.666 1.588 142.7 22.6 9.1 15.7 2010 09 16 01 38.11 -18 20.8 0.677 1.611 145.9 20.5 9.3 15.7 2010 09 21 01 35.82 -19 04.3 0.691 1.635 148.7 18.6 9.5 15.7 2010 09 26 01 32.78 -19 38.1 0.710 1.660 151.0 17.0 9.8 15.8 2010 10 01 01 29.21 -20 00.9 0.732 1.685 152.5 15.9 10.0 15.8

7 81P/Wild 2

Comet Wild 2 until a couple of weeks ago was reported having a visual magnitude of 10 to 10.5 thru mid-June. Today the comet is fading and by most estimates it has faded to around 11 th magnitude and may require reasonably dark skies to observe it. The comet is presently located in the eastern region of Virgo and is undergoing retrograde motion and is expected to continue in such motion until mid June. Virgo is now up in early evening skies a couple of hours after sunset on 24 June and the comet is presently located in the SE region of Virgo heading southeast towards . None of the distinguishing stars in this immediate area of the sky are brighter than 6.5 th magnitude, so look for a pair of K0 class stars about 5 minutes of RA to the West of Wild 2. These stars are known as HD 125059 and HD 124973 at visual magnitudes of 6.62 and 6.48 respectfully. After that the comet will move thru a non distinguishing area of Libra in its West central region of Libra for most of the month of July. Expect Wild 2 is expected to pass a line between Xi 1 Librae and Mu Librae by 23 July with an angular separation of ~2.6° between the two stars as the comet will be about 2/3 of that gap from Mu Librae.

The solar elongation of the comet will have decreased to 104° on 23 July with a solar distance 2.1397 AU and a distance from Earth of 1.6556 AU with a visual magnitude 13.1. Wild 2 will move thru Libra during the month of August and will move about 1/3° to the north of Omicron Librae and will have dimmed to visual magnitude 13.8 before dawn on 13 August. Omicron Librae has a spectral type F0III at a visual magnitude 6.30 and a closer star halfway to Wild 2 on that day is HD 136406 a K0 class star about a magnitude fainter than o Librae. 81P will move about 0.59° to the north of Zeta 3 Librae during the late afternoon/evening of 19 August. The comet will have faded to 14 th visual magnitude with a reduced solar elongation while moving further away from both the Earth and the Sun at distances further away than Mars is from the Sun!

(See Ephemeris Data for Wild 2 on next page!)

8 IAU MPC Ephemeris data for 81P/Wild 2: Date TT RA(2000) Decl. Delta r Elong. Phase m1 m2 2010 06 28 14 23.50 -09 08.3 1.281 1.998 120.4 26.0 12.0 20.2 2010 07 03 14 28.41 -09 47.6 1.349 2.025 117.0 26.6 12.2 20.4 2010 07 08 14 33.70 -10 27.6 1.420 2.052 113.7 27.0 12.4 20.5 2010 07 13 14 39.35 -11 07.9 1.493 2.080 110.5 27.2 12.6 20.7 2010 07 18 14 45.32 -11 48.4 1.568 2.108 107.4 27.4 12.8 20.8 2010 07 23 14 51.60 -12 28.7 1.645 2.136 104.3 27.5 13.0 21.0 2010 07 28 14 58.14 -13 08.6 1.724 2.164 101.2 27.4 13.2 21.1 2010 08 02 15 04.91 -13 48.0 1.805 2.193 98.2 27.3 13.4 21.2 2010 08 07 15 11.91 -14 26.5 1.886 2.222 95.2 27.0 13.6 21.3 2010 08 12 15 19.11 -15 04.2 1.970 2.251 92.3 26.7 13.8 21.4 2010 08 17 15 26.50 -15 40.8 2.054 2.280 89.4 26.4 13.9 21.5 2010 08 22 15 34.06 -16 16.2 2.139 2.309 86.5 25.9 14.1 21.6 2010 08 27 15 41.76 -16 50.3 2.225 2.338 83.6 25.4 14.3 21.7 2010 09 01 15 49.61 -17 22.9 2.311 2.368 80.7 24.9 14.4 21.8 2010 09 06 15 57.57 -17 54.0 2.398 2.397 77.8 24.3 14.6 21.9 2010 09 11 16 05.66 -18 23.5 2.485 2.427 75.0 23.6 14.8 22.0 2010 09 16 16 13.85 -18 51.4 2.571 2.456 72.1 22.9 14.9 22.1 2010 09 21 16 22.13 -19 17.5 2.658 2.486 69.2 22.2 15.1 22.2

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