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ALPO Comet News for March 2019

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#1 Carl H.

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Posted 02 March 2019 - 10:00 PM

ALPO COMET NEWS FOR MARCH

 

2019
 
2019-March-2
 

 


The “bright” comets of March share some common traits this month. All of them are now past perihelion, fading, and evening objects. Only one comet can be considered an easy backyard object. C/2018 Y1 (Iwamoto) starts the month around 8th magnitude but will have faded to 10-11th magnitude by the end of the month.

 

Bright Comets (magnitude < 10)


 


C/2018 Y1 (Iwamoto) - The brightest comet of the month is long-period comet C/2018 Y1 (Iwamoto), a dynamically old long-period comet that last reached perihelion ~1350 years ago. Around the time of its perihelion on February 6 at 1.28 au and closest approach to Earth on February 12 at 0.30 au, Iwamoto brightened to around magnitude 6.5. Though only a few weeks past closest approach, Iwamoto has already faded to magnitude 8.0 and will further fade to 10.6 by the end of the month. This month, it is an evening object moving through the northern constellations of Auriga and Perseus.

 


C/2018 Y1 (Iwamoto)
T = 2019-Feb-06  q = 1.28 au   Long-Period comet - dynamically old


    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01   8.0   05 26  +35 04   1.329   0.691   103    Aur


2019-03-06   8.7   05 02  +34 37   1.349   0.863    93    Aur
2019-03-11   9.1   04 47  +34 12   1.373   1.037    85    Aur
2019-03-16   9.5   04 38  +33 52   1.401   1.210    78    Aur
2019-03-21   9.9   04 32  +33 37   1.432   1.379    72    Per
2019-03-26  10.2   04 28  +33 28   1.465   1.544    66    Per
2019-03-31  10.6   04 26  +33 22   1.501   1.703    61    Per


 

Faint Comets (between magnitude 10 and 13)


 

38P/Stephan-Oterma - So long, 38P/Stephan-Oterma! Small aperture visual observers have probably already lost sight of this comet. Larger aperture visual observers should be able to track it for another month or so. It will be interesting to see how long CCD observers can image 38P. Will it be lost due to faintness or due to a low solar elongation sometime in August? This month the comet should fade from around magnitude 12.0  to 13.0 as a northern evening object in Lynx. If you missed Stephan-Oterma this time, you’ll need to wait till 2056 for another chance.
 
38P/Stephan-Oterma                                    
T = 2018-Nov-10  q = 1.59 au   Short-Period comet  Period = 38.0 yr


    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01  11.9   08 29  +46 12   2.084   1.288   132    Lyn


2019-03-06  12.1   08 32  +45 36   2.122   1.358   129    Lyn
2019-03-11  12.3   08 35  +44 55   2.161   1.431   125    Lyn
2019-03-16  12.4   08 39  +44 11   2.200   1.507   122    Lyn
2019-03-21  12.6   08 43  +43 23   2.240   1.586   119    Lyn
2019-03-26  12.7   08 47  +42 34   2.280   1.668   115    Lyn
2019-03-31  12.9   08 53  +41 42   2.320   1.753   112    Lyn
 
   


 

46P/Wirtanen - Back in December this comet peaked at around magnitude 4.0 or a little brighter. It is now 3 months past perihelion and rapidly fading from 10th to 12th magnitude as it drifts south among the stars of Ursa Major and Leo Minor in the evening sky. Wirtanen’s next return in 2024 is horrible with the comet at a solar elongation of 10 degrees at perihelion. The following return in 2029 will provide the next opportunity to easily observe this comet.
 
46P/Wirtanen                                           


T = 2018-Dec-12  q = 1.06 au   Short-Period comet  Period = 5.4 yr


    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01  10.0   09 38  +45 47   1.459   0.557   139    UMa


2019-03-06  10.3   09 40  +44 05   1.500   0.610   138    UMa
2019-03-11  10.6   09 43  +42 24   1.542   0.666   136    UMa
2019-03-16  11.0   09 46  +40 43   1.584   0.726   134    LMi
2019-03-21  11.3   09 50  +39 05   1.627   0.788   131    LMi
2019-03-26  11.6   09 54  +37 29   1.669   0.854   129    LMi
2019-03-31  11.9   09 58  +35 55   1.712   0.923   126    LMi


 

64P/Swift-Gehrels - Most of us have already said farewell to 64P/Swift-Gehrels. It will fade from magnitude 12.0 to 13.2 this month as its moves through Taurus and Gemini. Its next return in 2028 is very poor. The next return that comes close to rivaling 2018 won’t be till 2046.

 

64P/Swift-Gehrels                                       


T = 2018-Nov-03  q = 1.39 au   Short-Period comet  Period = 8.9 yr.


    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01  12.0   05 10  +25 07   1.937   1.517    99    Tau


2019-03-06  12.2   05 21  +24 51   1.974   1.601    96    Tau
2019-03-11  12.4   05 31  +24 35   2.011   1.687    94    Tau
2019-03-16  12.6   05 41  +24 18   2.049   1.775    91    Tau
2019-03-21  12.8   05 51  +24 01   2.087   1.864    88    Tau
2019-03-26  13.0   06 01  +23 44   2.125   1.955    86    Gem
2019-03-31  13.2   06 11  +23 25   2.163   2.046    83    Gem


 

123P/West-Hartley - Comet 123P/West-Hartley was first reported by Richard West of the European Southern Observatory on 1989 May 11. West was also the discoverer of the great comet C/1975 V1 (West). West found the comet as a trailed object on a 60-min photographic exposure taken with the ESO 1.0-m schmidt as part of an extension to the all-southern sky ESO Quick Blue Survey. An accidental discovery was made by Malcolm Hartley on a J-band survey plate taken on May 28 with the UK Schmidt.

 

This year 123P has been observed as bright as magnitude ~12.2. This is the brightest it has ever gotten. Part of the reason may be increased activity as the comet experienced a small outburst in early January. Perihelion occurred on February 5 at 2.13 au with closest approach to Earth on February 27 at 1.20 au. This year marks 123P’s best apparition of the four since its 1989 discovery.

 

123P/West-Hartley                                       


T = 2019-Feb-05  q = 2.13 au   Short-Period comet  Period = 7.6 yr.


    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01  12.8   11 26  +31 58   2.135   1.200   154    UMa


2019-03-06  12.8   11 22  +31 54   2.139   1.204   154    UMa
2019-03-11  12.9   11 18  +31 42   2.144   1.214   152    UMa
2019-03-16  12.9   11 14  +31 21   2.149   1.229   150    UMa
2019-03-21  13.0   11 10  +30 50   2.155   1.250   147    UMa
2019-03-26  13.1   11 06  +30 12   2.161   1.275   144    UMa
2019-03-31  13.2   11 04  +29 26   2.169   1.306   140    LMi


 

C/2016 M1 (PANSTARRS) - This comet is still with us. It also is the only comet brighter than 12th magnitude that is solely a southern hemisphere object. Now 7 months after perihelion, C/2016 M1 continues to slowly fade at around 11th magnitude.

 


C/2016 M1 (PANSTARRS)


T = 2018-Aug-10  q = 2.21 au   Long-Period comet - dynamically old
    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01  11.0   03 42  -62 06   3.162   3.258    76    Ret


2019-03-06  11.1   03 50  -59 49   3.200   3.297    76    Ret
2019-03-11  11.1   03 58  -57 35   3.237   3.340    76    Ret
2019-03-16  11.2   04 06  -55 25   3.276   3.387    75    Dor
2019-03-21  11.2   04 13  -53 19   3.314   3.437    75    Dor
2019-03-26  11.3   04 21  -51 17   3.353   3.490    74    Dor
2019-03-31  11.3   04 28  -49 21   3.392   3.546    73    Dor


 

C/2018 L2 (ATLAS) - Comet ATLAS passed perihelion on 2018 December 2 at a distance of 1.71 au from the Sun. The brightness of this comet has been problematic with a large scatter of 2-3 magnitudes. The predictions below follow the reported brightness of the majority of observers so the comet may actually be somewhat brighter. Complicating things further, C/2018 L2 will be moving against the dense Milky Way star fields of Lacerta and Andromeda.
 


 

C/2018 L2 (ATLAS)


T = 2018-Dec-02  q = 1.71 au   Long-Period comet - dynamically old


    Date     Mag    R.A.   Decl.     r       d    Elong  const


2019-03-01  11.8   22 12  +37 37   2.056   2.614    46    Lac


2019-03-06  12.1   22 29  +38 46   2.091   2.664    46    Lac
2019-03-11  12.4   22 45  +39 50   2.127   2.716    45    Lac
2019-03-16  12.7   23 02  +40 48   2.164   2.771    44    And
2019-03-21  13.0   23 18  +41 41   2.203   2.827    43    And
2019-03-26  13.3   23 34  +42 30   2.241   2.885    42    And
2019-03-31  13.6   23 49  +43 13   2.281   2.944    41    And
 

 

New Discoveries
 
A/2019 C1 - The ATLAS telescopes on Mauna Loa discovered this inactive long-period comet on February 5 at 18th magnitude. There is a reasonable possibility that this comet is already active even though no cometary features have been detected. Perihelion will occur on May 6 at 6.58 au. If still inactive, it will not get any brighter than it is now. With an absolute magnitude of 10.0 and assuming no activity, its nucleus may be quite large at 60+ km in diameter. If the object is an active comet, the nucleus is likely to be much much smaller.

C/2019 B3 (PANSTARRS) - The Pan-STARRS1 telescope first spotted this comet on January 24 at 19th magnitude. Its distant perihelion (q = 6.82 au) won’t be till 2021 January 19 though the comet is unlikely to get much brighter.
 
As always, the Comet Section is happy to receive all comet observations, whether images, drawings, magnitude estimates, and even spectra. Please send your observations via email to < carl.hergenrother @ alpo-astronomy.org >.


- Carl Hergenrother (ALPO Comet Section Coordinator)


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#2 phillip

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Posted 03 March 2019 - 12:59 PM

Nice info.

We are well overdue for a big one. Perhaps a surprised encounter!

#3 Rich (RLTYS)

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Posted 08 March 2019 - 01:05 PM

Thanks for the info. I look forward to reading ALPO Comet News each month.waytogo.gif bow.gif

 

Rich (RLTYS)


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#4 Special Ed

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Posted 11 March 2019 - 11:10 AM

Thanks, Carl.  smile.gif 




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