The Professor Comet’s Report 1

Mr. Justin J McCollum (BS, MS Physics) Lab Physics Coordinator Dept. of Physics Lamar University

Welcome to the comet report which is a monthly article on Astronomy Sketch of the Day the observations of comets by the amateur astronomy Courtesy of James & Forrest Maxwell community and comet hunters from around the world! 4 April 2012 This article is dedicated to the latest reports of available comets for observations, current state of those comets, future predictions, & projections for observations in comet astronomy! Mid Spring – May 2012 The Professor Comet’s Report 2 The Current Status of the Predominant Comets for May 2012!

Comets Designation Orbital Magnitude Trend Observation Visibility (IAU – MPC) Status Visual (Range in (Night Sky Location) Period Lat.) (alt. ≥ 30˚) Garradd 2009 P1 C 8.0* Fading 90°N – 50°S S region of moving S then 8 PM – 1 AM SSE into the N region of . CDT Giacobini - 21P P 9 – 10 Fading Poor N/A Zinner Elongation Lost in the daytime Glare!

LINEAR 2011 F1 C 11 .6* Brightening 90°N – 25°S Undergoing retrograde motion (1 – 5) AM CDT between Boötes and Draco thru the late Spring. LINEAR C/2011 UF305 C 11.8* Rapid 90°N – 10˚N Circumpolar comet for May (1:30 - 5:00) AM Brightening (N region of Cepheus) CDT NEAT 246P/2010 V2 P 12.3* - 13 Possible 65˚N - 60˚S Undergoing retrograde motion Sunset – 3 AM Steadiness in the N central region of Virgo CDT & S boundary of Coma Berenices until late June. McNaught 2011 Q2 C 12.5 Fading 70˚N – 25˚N Currently in the SE region of Visible at Andromeda moving ENE alt. < 30˚ (3:30 – 5:00) AM towards Perseus. CDT McNaught 2009 F4 C 12.8* - 14 Steady Poor N/A Elongation Lost in the daytime Glare!

*Visual Magnitude determined from last known field observation report!

Comets with visually reported at visual magnitude values fainter than 13 or 13.5 are not reported on this list! Mid Spring – May 2012 The Professor Comet’s Report 3 Ephemeris Data Terminology

Ephemeris Term Definition (plus additional comments)

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, minutes, and seconds.

Dec (2000) based on the Epoch J2000 (latitudinal coordinate for the night sky) measured in degrees, arcminutes, and arcseconds.

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

R The solar distance measured in AUs (the distance between the comet or comet – like body and the Sun)!

Elongation 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 M1: The visual magnitude of the celestial object as observed on the surface of the Earth at sea level. (Note M1 values predicted by the Minor Planet Center can differ from actual visual reports obtain in the field!)

M2 The nuclear magnitude of the Comet which is also the visual magnitude of the false nucleus. (Rarely shown on a Comet’s ephemeris data spreadsheet unless all values show a visual brightness value above 19th magnitude!)

“/min The progression or motion across the sky as measured in arcseconds per minute.

P.A. Position angle while undergoing motion in the celestial sky. (P.A. is the same method applied to binary with starts at N goes counterclockwise in an easterly direction!)

Moon Phase A Numerical value for designating the phases of the Moon on a scale of (0.00 – 1.00): A New Moon = 0.00, Waxing or Waning Crescent = (0.01 - 0.49), Half Moon (1st or Last Quarter = 0.50), Waxing or Waning Gibbous = (0.50 – 0.99), & Full Moon = 1.00

Foreshortening The appearance of the comet’s tail due to the geometric orientation between the Earth and a Comet. (% Fore.) (100% means the comet’s tail is parallel with the face of the Earth where as 0% means the tail is exactly perpendicular with respect to the face of the Earth!)

Mid Spring – May 2012 The Professor Comet’s Report 4

All observations of comets are broken down into three factors: estimating Degree of Condensation (DC) magnitudes for light curves to predict future brightness, coma observations, and observations that concern with a comet’s tail(s). For the coma or a comet’s head there two characteristic features that are important for study: Degree of condensation (DC) and coma size measured in arcminutes. The classification system for determining the DC is based on a positive integer system from 0 to 9 as shown below.

DC value Definition to numerical DC designation

0 Diffuse coma of uniform brightness

1 Diffuse coma with slight brightening towards center

2 Diffuse coma with definite brightening towards center

3 Centre of coma much brighter than edges, though still diffuse

4 Diffuse condensation at centre of coma

5 Condensation appears as a diffuse spot at centre of coma – described as moderately condensed 6 Condensation appears as a bright diffuse spot at centre of coma

7 Condensation appears like a that cannot be focused – described as strongly condensed

8 Coma virtually invisible

9 Stellar or disk like in appearance

Mid Spring – May 2012 The Professor Comet’s Report 5 A Synopsis of the Predominant Comets for the Spring & Summer 2012! Comet Garradd is now setting in the early to mid evening in the western skies with the constellations of the winter sky as we progress thru the middle of the Spring season in the month of May! Currently the comet is continuing to fade as it moves thru the Asteroid belt on its trajectory to the outer solar system and back to its origins most likely in the Kuiper Belt. The latest field reports give Garradd a visual magnitude brightness of 8.0 as of late April. Garradd was last reported on 28 April with an angular diameter of only 5 arcminutes (~2.6% the size of an average full Moon) with a DC of 5. There are no further reports on the conditions of the fan - shaped tail given that is now much harder to see with the rapid fading of comet Garradd as the Winter constellations disappear from the night sky by the end of May. However, both Lynx and Cancer will still be visible even after sunset up until the beginning of July. Therefore, May is the month to observe at least the coma of Garradd, but the central condensate (nucleus) of the coma will end up having a stellar magnitude of 11.0 by mid June. However, some predictions place the comet’s visibility at ‘non – observable’ before the end of early June with its solar elongation decreasing from 84˚ (1 May) to 60˚ (May 30). Therefore, May is likely the last month in which to observe comet Garradd before it is lost in the daytime solar glare until it is visible again in late October, but the comet will have faded to 13th magnitude while moving south thru the constellation of Sextans!

There are no other comets that are prominent right now nor are any of the known cometary bodies currently being monitored are expected to get brighter than 8th or 8th magnitude expect comet 96P/Machholz 1 which is expected to be visible this summer during the months of July and August in the evening hours before midnight! Comet Machholz 1 is currently progressing eastward thru the northern edge of the southern constellation of Grus ‘the Crane’ and will move into the neighboring constellation of Sculptor by late April and move quickly thru the ‘Winter Hexagon’ asterisms of the winter constellations from mid – June and most of early – July lost in the daytime glare. However, once it is visible sometime in mid July it will be located between Lynx and Cancer low in the evening skies just after sunset with the planet Mars setting during the months of mid – Summer. As we move into the month of August the comet will have shifted its position further east towards the following in succession; Coma Berenices (25 July – 6 Aug), Virgo (6 – 7 Aug), Boötes (7 – 13 Aug), Virgo in its NE region (13 – 22 Aug), and Libra thru the end of August. Machholz 1 will reach a predicted maximum brightness of visual magnitude 7.0 by the month of July. However, the comet has a solar elongation below 60˚, so it will be difficult to see positioned at a sky altitude below 30˚ during the hours of dusk making a very difficult object to observe thru so much air and the effects of atmospheric refraction and mirage effects close to the distant horizon! Current predictions are placing this comet as a maximum brightness of visual magnitude -0.l (~6% brighter than Arcturus) and located in the constellation of Gemini the period of 1 -2 July, but with a solar elongation of 1 – 3 degrees!

Mid Spring – May 2012 The Professor Comet’s Report 6 A Synopsis of the Predominant Comets for the Spring & Summer 2012! Once future prospect is in 2013 with the discovery of C/2011 L4 (PanSTARRS) discovered using 1.8m Pan – STARRS 1 RC telescope on the Hawaiian islands, USA the night of 6 June 2011 between 09:36 – 10:32 UTC or 04:36 – 05:32 AM local Hawaiian time. Comet PanSTARRS L1 is predicted to become the ‘Great Comet of 2013’ reaching a maximum brightness of visual magnitude -1 on the evening of 10 – 11 March 2013, but with the unfortunate solar elongation of only 15˚ while residing along the constellation boundary between Cetus and Pisces close to where the planet Uranus is currently resides. Right at the present the comet is undergoing a wide retrograde motion which began in late – Sept, 2011 and ends also in late – Sept, 2011 moving from Libra to Ophiuchus thru Scorpius and back to Libra. There are no opportunities to observe the comet based on the current ephemeris and orbital data calculated for it so far, the comet will be at solar elongation values of less than 18˚ and 61˚ when it is brighter than 12th and fading to 8th magnitude upon reaching and receding from perihelion respectfully. This period lasts from 8 Nov 2011 thru 8 May 2012 when it is moving SE from Lupus (The Wolf) across the constellations of the Summer sky towards Microscopium and then head NE thru the Autumnal sky past Andromeda and into Cepheus by early May, 2012! C/2011 L4 is predicted to reach a perihelion of 0.30 AU or 27,870,000 mi (44,842,830 km) the period of 10 - 12 March 2011 around the time of maximum brightness and perigee of 1.10 AU or 102,190,000 mi (164,423,371 km) the period of 3 – 8 March 2011 prior to perihelion. Models in predicting the future path of non – periodic comets can change and the future data gathering on the projected path and orbital elements can change overtime and this includes comet PanSTARRS L1; stay tuned for future change in details if any!

Mid Spring – May 2012 The Professor Comet’s Report 7 C/2009 P1 Garradd Figure 1: Garradd P1 projected path across the Spring Constellations: 30 Mar – 24 June, 2012!

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Courtesy of SkyTools 3 Profession Ed, 2012.

Mid Spring – May 2012 The Professor Comet’s Report 8 C/2009 P1 Garradd Figure 2: Close up of Garradd ‘s projected path from ‘22 Apr – 1 Jun’ 2012!

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Courtesy of SkyTools 3 Profession Ed, 2012.

Mid Spring – May 2012 The Professor Comet’s Report 9 C/2009 P1 Garradd Figure 3: Stars & DSOs near Garradd ‘s projected path from ‘22 Apr – 1 Jun’ 2012!

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NGC 2782 E W +

HD 77912 S

32 Lyn 33 Lyn HIP 45661 CY Lyn

Elvashak ACO 779+ NGC 2683 σ2 Cnc + σ3 Cnc σ1 Cnc RS Cnc 57 Cnc NGC 2679 61 Cnc + 46 Cnc τ Cnc

ι Cnc NGC 2608 + ρ2 Cnc ρ1 Cnc

Courtesy of SkyTools 3 Profession Ed, 2012.

Mid Spring – May 2012 The Professor Comet’s Report 10 C/2009 P1 Garradd Figure 3: Garradd’s projected path from Lynx thru Cancer from ‘1 May – 3 Jul’ 2012!

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Courtesy of Winnie’s Comet Pages, 2012. Mid Spring – May 2012 The Professor Comet’s Report 11 C/2009 P1 Garradd Figure 4: Garradd’s projected path thru Lynx and towards Cancer from (1 – 15) May 2012!

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Courtesy of Winnie’s Comet Pages, 2012. Mid Spring – May 2012 The Professor Comet’s Report 12 C/2009 P1 Garradd Figure 4: Garradd’s projected path thru Cancer from (14 May – 3 Jun) 2012!

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Courtesy of Winnie’s Comet Pages, 2012. Mid Spring – May 2012 The Professor Comet’s Report 13 Bright Stars in Lynx & Cancer along the Spring path of Comet Garradd

Star Common Designations Vis. Mag Classification Stellar Attributes R.A. (2000) Dec (2000) Distance (lys)

HD 77912 HR 3612, SAO 61254, 4.58 G7 I None 9h 06m 31.7s +38˚27’08” 680 TYC 02983 – 1983 1

Maculata 38 Lyncis, HR 3690, 3.82/6.90 A3 V/A4 V, A6 Strange Binary 9h 18m 50.6s +36˚48’08” 120 HD 80081, HIP 45688 V, or F4 V (38 Lyn A is a λ Boötis star)

HIP 45661 HR 3686, HD 80024, 5.94 K0 V None 9h 18m 25.9s +35˚21’ 50” ~500 SAO 61387,

CY Lyncis HR 3528, HD 75896, 6.17 A4 III Variable Type: 8h 53m 55.7s +35˚ 32’ 18” 950 SAO 61117 Rotating Ellipsoidal

Elvashak Alpha (α) Lyn, 40 Lyn, 3.14 K7 III Suspected Variable 9h 21m 3.1s +34˚23’33” 220 HR 3705, HD 80493 (+/- 0.05 Mag)

σ1 Cancri 51 Cnc, HR 3519, 5.67 A2 V Suspected Variable 8h 52m 34.6s +32˚ 28’ 27” 200 HD 75698, (Max. Vis Mag. 5.66) TYC 02485 – 2094 1

57 Cancri HR 3799, HD 82621, 5.40/6.60 G7 III/K0 V Stellar Binary 8h 54m 14.8s +30˚34’45” 370 SAO 27298, TYC 03432 – 1450 1

61 Cancri HR 3563, HD 76572, 6.25 F6 V None 8h 57m 58.7s +30˚ 14’ 02” 160 SAO 61157, TYC 02485 – 2097 1

τ Cancri 72 Cnc, HR 3621, 5.46 F7 V Micro Variable ? 9h 8m 00.0s +29˚ 39’ 15” 260 HD 78235, SAO 80650, TYC 01957 – 1674 1

ι Cancri 48 Cnc, HR 3474, 6.58 A3 V None 8h 46m 40.0s +28˚ 45’ 54” ~190 HD 74738, SAO 80415, STF 1268B

ρ1 Cancri 55 Cnc, HR 3522, 5.96/13.15 G8 V/M3.5 – 4V Stellar Binary 8h 52m 35.4s +28˚ 19’ 48” 41 HD 75732, HIP 43587, (5 @ 55 Cnc A) SAO 80478

ρ2 Cancri 58 Cnc, HR 3540, 5.25 G6 V None 8h 55m 39.7s +27˚ 55’ 39” 570 HD 76219, HIP 43834 Mid Spring – May 2012 The Professor Comet’s Report 14 Common DSOs near the Spring path of Comet Garradd C/2009 P1

DSO Common Designations Vis. Mag Classification DSO Attributes R.A. (2000) Dec (2000) Distance (lys)

NGC 2782 Arp 215, 12.3 Spiral Hubble Type: SABa 9h 14m 05.2s 40˚ 06’ 47” *110 million MCG 7 – 19 – 36, (Intermediate/ peculiar, starburst UGC 4862, galaxy) PGC 26034 ACO 779 None 12.8 Abell Distance Index (0 – 7): 9h 19m 48.0s 33˚ 46’ 00” *300 million (brightest member) Galaxy 1 13.8 z = 0.02 (10th brightest member) Group NGC 2683 MCG 6 – 20 – 11, 10.0 Spiral Hubble Type: Sb 8h 52m 41.2s 33˚ 25’ 16” *25 million UGC 4641, Galaxy (Nearly Edge – On) P.A.: 44˚ PGC 24930 (NE – SW orientation) NGC 2679 MCG 5 – 21 – 14, 13.8 Barred Hubble Type: S0 8h 51m 32.9s 30˚ 51’ 55” *93.6 million UGC 4632, Lenticular (Face On/evident interaction with PGC 24884 Galaxy another galaxy) Hickson 37 HCG 37 12.1 Compact 5 members 9h 13m 35.6s 30˚ 00’ 51” *311 million Galaxy Group NGC 2608 Arp 12, 13.0 Spiral Hubble Type: Sb 8h 35m 17.2s 28˚ 28’ 26” *30.3 million MCG 5 – 20 – 27, Galaxy (Intermediate) P.A.: 64˚ UGC 4484, (ENE – WSW orientation) PGC 24111 One Supernova in 1983

*Current distances are based on the currently accepted age of the Universe at 13.732 billion yrs. which gives an H = 71.2 km/s/Mpc! 0 Mid Spring – May 2012 The Professor Comet’s Report 15 IAU MPC Ephemeris data for C/2009 P1 Garradd (February 2012):

Date CDT/CST R.A. (J2000) Decl. Delta r El. Ph. M1 % Fore. Sky Motion Moon Phase Moon Mag. h m s "/min P.A. (0.00 – 1.00) (Visual) 2012 05 01 000000 08 50 00.0 +37 55 15 2.195 2.313 83.7 25.7 9.3 57 1.24 184.3 0.69 -11.62 2012 05 02 000000 08 49 50.5 +37 26 01 2.221 2.323 82.9 25.5 9.4 57 1.22 183.5 0.79 -11.90 2012 05 03 000000 08 49 43.4 +36 57 21 2.246 2.332 82.1 25.4 9.4 57 1.19 182.7 0.88 -12.12 2012 05 04 000000 08 49 38.4 +36 29 14 2.272 2.341 81.3 25.2 9.5 57 1.17 181.9 0.94 -12.29 2012 05 05 000000 08 49 35.5 +36 01 39 2.297 2.350 80.4 25.0 9.5 58 1.15 181.1 0.99 -12.39 2012 05 06 000000 08 49 34.5 +35 34 35 2.323 2.360 79.6 24.9 9.6 58 1.13 180.2 1.00 -12.42 2012 05 07 000000 08 49 35.4 +35 08 02 2.348 2.369 78.8 24.7 9.6 58 1.10 179.4 0.98 -12.37 2012 05 08 000000 08 49 38.0 +34 41 58 2.374 2.378 78.0 24.5 9.6 59 1.08 178.6 0.94 -12.25 2012 05 09 000000 08 49 42.4 +34 16 22 2.400 2.387 77.1 24.3 9.7 59 1.07 177.8 0.87 -12.07 2012 05 10 000000 08 49 48.3 +33 51 14 2.425 2.397 76.3 24.2 9.7 59 1.05 177.0 0.78 -11.83 2012 05 11 000000 08 49 55.8 +33 26 33 2.451 2.406 75.5 24.0 9.8 59 1.03 176.2 0.68 -11.55 2012 05 12 000000 08 50 04.7 +33 02 18 2.477 2.416 74.7 23.8 9.8 60 1.01 175.4 0.57 -11.22 2012 05 13 000000 08 50 15.1 +32 38 28 2.503 2.425 73.9 23.6 9.8 60 1.00 174.6 0.47 -10.84 2012 05 14 000000 08 50 26.7 +32 15 03 2.528 2.434 73.1 23.4 9.9 60 0.98 173.8 0.37 -10.40 2012 05 15 000000 08 50 39.6 +31 52 02 2.554 2.444 72.3 23.2 9.9 61 0.96 173.0 0.28 -9.89 2012 05 16 000000 08 50 53.8 +31 29 25 2.580 2.453 71.4 23.0 10.0 61 0.95 172.2 0.19 -9.29 2012 05 17 000000 08 51 09.0 +31 07 09 2.605 2.463 70.6 22.8 10.0 61 0.94 171.4 0.12 -8.55 2012 05 18 000000 08 51 25.4 +30 45 16 2.631 2.472 69.8 22.6 10.0 62 0.92 170.7 0.07 -7.57 2012 05 19 000000 08 51 42.9 +30 23 44 2.657 2.481 69.0 22.4 10.1 62 0.91 169.9 0.03 -6.16 2012 05 20 000000 08 52 01.4 +30 02 33 2.682 2.491 68.2 22.2 10.1 62 0.90 169.1 0.01 -3.58 2012 05 21 000000 08 52 20.8 +29 41 42 2.708 2.500 67.4 21.9 10.1 63 0.89 168.3 0.00 1.29 2012 05 22 000000 08 52 41.2 +29 21 10 2.733 2.510 66.6 21.7 10.2 63 0.88 167.6 0.01 -4.81 2012 05 23 000000 08 53 02.4 +29 00 57 2.759 2.519 65.8 21.5 10.2 63 0.86 166.8 0.04 -6.82 2012 05 24 000000 08 53 24.5 +28 41 03 2.784 2.529 65.0 21.3 10.3 64 0.85 166.1 0.09 -8.06 2012 05 25 000000 08 53 47.4 +28 21 26 2.809 2.538 64.2 21.1 10.3 64 0.84 165.4 0.16 -8.96 2012 05 26 000000 08 54 11.1 +28 02 07 2.835 2.548 63.4 20.8 10.3 64 0.83 164.6 0.24 -9.67 2012 05 27 000000 08 54 35.5 +27 43 05 2.860 2.558 62.6 20.6 10.4 65 0.83 163.9 0.33 -10.25 2012 05 28 000000 08 55 00.6 +27 24 19 2.885 2.567 61.8 20.4 10.4 65 0.82 163.2 0.43 -10.74 2012 05 29 000000 08 55 26.3 +27 05 49 2.910 2.577 61.1 20.1 10.4 66 0.81 162.5 0.54 -11.16 2012 05 30 000000 08 55 52.8 +26 47 34 2.935 2.586 60.3 19.9 10.5 66 0.80 161.9 0.65 -11.52 2012 05 31 000000 08 56 19.8 +26 29 34 2.959 2.596 59.5 19.7 10.5 66 0.79 161.2 0.76 -11.82 All ephemeris data is calculated based on the Geographical location of the George Observatory, SE Texas, United States.

29˚22’30” N, 95˚35’37” W Mid Spring – May 2012 The Professor Comet’s Report 16 Overview of the Orbital Differences for Comets!

Figure 6.1 Figure 6.2

P – Periodic Comets

C – Non Periodic Comets

Comet Garradd is the perfect example of a non – periodic comet! The path is hyperbolic in nature. Comet 45P/Honda – Mrkos – Pajdusakova however is the perfect example of a periodic comet which is elliptical in nature.

Figures 6.1 & 6.2 are of Comet C/Garradd 2009 P1 and Figure 6.3 below is off 45P.

All images were obtained from the JPL Solar System Dynamics/Small Body Database Browser . Courtesy of NASA/JPL/CalTech

Figure 6.3

Mid Spring May 2012 The Professor Comet’s Report 17 Fainter Predominant Comets for Spring 2012

21P/Giacobini - Zinner

NEAT 246P/2010 V2 Mid Spring – May 2012 18 Fainter Predominant Comets for Spring 2012 The Professor Comet’s Report (Continued)

LINEAR C/2011 UF305

C/2009 F4 McNaught

C/2011 Q2 McNaught

Early Spring – April 2012