Tuesday, November 2, 2021

New Comet P/2021 U3 (Attard-Maury)

CBET 5064 & MPEC 2021-V21, issued on 2021, November 02, announce the discovery of a new comet (magnitude ~19)  by A. Maury and G. Attard on CCD images taken on October 24.3 UT  with the 0.28-m f/2.2 Rowe-Ackermann Schmidt astrograph at San Pedro de Atacama, Chile in the course of the  MAP (W94) survey.  The new comet has been designated P/2021 U3 (Attard-Maury). This is the 4th amateur comet discovery of 2021. It is also the second comet discovered using the synthetic tracking technique (using TYCHO software).

Stacking of 51 unfiltered exposures, 60 seconds each, obtained remotely on 2021, Oct. 27.3 from X02 (Telescope Live, Chile) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 6" arcsecond in diameter and a tail 6" long in PA 275 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Stacking of 66 unfiltered exposures, 60 seconds each, obtained remotely on 2021, Oct. 29.9 from G18  (ALMO Observatory, Italy) through a 0.30-m f/4 reflector + CCD, shows that this object is a comet with a compact coma about 5" arcsec in diameter and a tail 6" long in PA 270 (Observers A. Valvasori & E. Guido).

Our confirmation images (click on the images for a bigger version; made with TYCHO software by D. Parrott)


 


MPEC 2021-V21, assigns the following preliminary elliptical orbital elements to comet  P/2021 U3 (Attard-Maury): T 2021 Oct. 25.43; e= 0.55; Peri. =  335.48; q = 1.88 ;  Incl.= 70.05.

According to CBET 5064 "the comet passed 0.59 AU from Jupiter in 1983 October (though the orbital period is uncertain by well over a month). A search for earlier observations in archival astrometry produced nothing".

 

Credit: MPC

by Ernesto Guido

Friday, October 1, 2021

New Comet P/2021 Q5 (ATLAS)

CBET 5029 & MPEC 2021-R98 , issued on 2021, September 06, announce the discovery of a new comet (magnitude ~17) on CCD images taken on August 29.6 UT with a 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program. The new comet has been designated P/2021 Q5 (ATLAS)

Stacking of 58 unfiltered exposures, 30 seconds each, obtained remotely on 2021, September 03.1 from G18  (ALMO Observatory, Italy) through a 0.30-m f/4 reflector + CCD, shows that this object is a comet with a compact coma about 8" arcsec in diameter and a tail 10" long in PA 270 (Observers A. Valvasori & E. Guido).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)



MPEC 2021-R98, assigns the following preliminary orbital elements to comet  P/2021 Q5 (ATLAS): T 2021 August 30.34; e= 0.61; Peri. =  180.81; q = 1.23 ;  Incl.= 10.72. 


Credit: MPC


by Ernesto Guido

Thursday, September 30, 2021

New Comet C/2021 Q4 (Fuls)

CBET 5028 & MPEC 2021-Q102, issued on 2021, August 31 & September 02, announce the discovery of a new comet (magnitude ~20) on CCD images taken on August 26.2 UT with the Mt. Lemmon Survey (G96) 1.5-m reflector. The new comet has been designated C/2021 Q4 (Fuls)

Stacking of 30 unfiltered exposures, 120 seconds each, obtained remotely on 2021, August 29.9 from Z08 (Telescope Live, Oria) through a 0.7 m f/8 Ritchey Chretien + CCD, shows that this object is a comet with a compact coma about 8" arcsec in diameter elongated toward PA 275 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)




MPEC 2021-Q102, assigns the following preliminary orbital elements to comet C/2021 Q4 (Fuls): T 2023 June 10.66; e= 1.0030276; Peri. =  147.01; q = 7.56 ;  Incl.= 71.47. The comet will pass 2.45 AU from Saturn on 2025 Apr. 30 UT.

Credit: MPC


by Ernesto Guido

Monday, August 2, 2021

New Comet C/2021 O3 (PANSTARRS)

CBET 5009 & MPEC 2021-P05, issued on 2021, August 01, announce the discovery of a new comet (magnitude ~20) on CCD images taken on July 26.5 UT with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala. The new comet has been designated C/2021 O3 (PANSTARRS)

Stacking of 15 unfiltered exposures, 240 seconds each, obtained remotely on 2021, July 30.3 from X02 (Telescope Live, Chile) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 8" arcsecond in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)





MPEC 2021-P05, assigns the following preliminary orbital elements to comet C/2021 O3 (PANSTARRS): T 2022 Apr. 20.49; e= 1.0; Peri. =  299.88; q = 0.28 ;  Incl.= 56.72


Credit: MPC

This comet could become visible to the naked eye in 2022, reaching magnitude ~5. Below you can see a graph generated using the software Orbitas and showing the predicted magnitude (in red) versus its elongation from the Sun. Anyway, as always with comets, the future magnitudes reported here are only indicative. 


By Ernesto Guido

Saturday, July 24, 2021

New Comet C/2021 N3 (PANSTARRS)

CBET 5003 & MPEC 2021-O39, issued on 2021, July 22, announce the discovery of a new comet (magnitude ~20.5) on CCD images taken on July 13.5 UT with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala (numerous pre-discovery observations going back an additional month were later identified). The new comet has been designated C/2021 N3 (PANSTARRS)

Stacking of 16 unfiltered exposures, 180 seconds each, obtained remotely on 2021, July 14.3 from X02 (Telescope Live, Chile) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 9" arcsecond in diameter elongated toward PA 230 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)



MPEC 2021-O39, assigns the following preliminary orbital elements to comet C/2021 N3 (PANSTARRS): T 2020 Aug. 13.96; e= 0.96; Peri. =  303.99; q = 5.69 ;  Incl.= 26.67


Credit: MPC


by Ernesto Guido

Friday, July 23, 2021

New Comet P/2021 N2 (Fuls)

CBET 5000 & MPEC 2021-N137, issued on 2021, July 15, announce the discovery of a new comet (magnitude ~18.3) on CCD images taken on July 09.4 UT with the Catalina Sky Survey's 0.68-m Schmidt reflector (pre-discovery Catalina observations from June 27 were identified later). The new comet has been designated  P/2021 N2 (Fuls)

Stacking of 28 unfiltered exposures, 60 seconds each, obtained remotely on 2021, July 10.1 from Z08 (Telescope Live, Oria) through a 0.7 m f/8 Ritchey Chretien + CCD, shows that this object is a comet with a compact coma about 8" arcsec in diameter and a tail 10" long in PA 250 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Our confirmation image (click on the images for a bigger version; made with TYCHO software by D. Parrott)


MPEC 2021-N137, assigns the following preliminary elliptical orbital elements to comet P/2021 N2 (Fuls): T 2021 Oct. 28.30; e= 0.47; Peri. =  174.65; q = 3.82 ;  Incl.= 12.99


Credit: MPC


by Ernesto Guido

Tuesday, June 29, 2021

Giant Oort Cloud Comet C/2014 UN271 (Bernardinelli-Bernstein)

On 2021 June 19, the circular MPEC 2021-M53 of Minor Planet Center announced the discovery of an asteroidal object by astronomers P. Bernardinelli & G. Bernstein (University of Pennsylvania) that they found in CCD exposures obtained with the 4.0-m reflector at Cerro Tololo Interamerican Observatory in the course of the "Dark Energy Survey", and which they reported as a previously unknown member of the Oort Cloud. The reported astrometry was spanning from 2014 Oct. 20 to 2018 Nov. 8. The new object was designated 2014 UN271. It was hidden among data collected by the 570-megapixel Dark Energy Camera (DECam) mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile and was announced only now because, in the words of one of the discoverers, "finding TNOs with DES is a massive computational problem (my PhD was solving this problem). The search itself took 15~20 million CPU-hours, and the catalog production from our 80,000 exposures probably took more than that!"

According to the orbit calculated using data from 2014 to 2018, this object is likely to be a comet from the inner edge of the Oort Cloud. But 2014 UN271, despite its typically cometary orbit, appeared completely stellar in these archival images when it moved from 29 to 23 AU (for comparison, Pluto is 39 au from the Sun, on average). Below a simulation (made by T. Dunn) of the orbit of comet C/2014 UN271 showing it path in the Solar System from 1985 to 2049. 


A few days after the discovery announcement, 2014 UN271 has been found to show cometary appearance in new CCD images obtained by observers at station codes L81 & K93.Basically this object, that was first seen as an asteroid of magnitude ~22 by DES in 2014 at a distance of 29 AU, approaching the Sun was growing his coma and tails. As of June 2021, it was 20 AU from the Sun shining at a magnitude ~20.After the discovery of the cometary coma, the new comet has been designated C/2014 UN271 (Bernardinelli-Bernstein). This comet will reach perihelion, its closest point to the Sun, in January 2031 at about ~11 AU away from the Sun.

The absolute magnitude of C/2014 UN271 measured in DES images dated back to 2014-2018, has a value of H = 7.8 which suggests the body could be around 100–200 kilometers across. This value for the size of this comet is valid if we assume there was no contribution from a dust coma in that images. For scale the nucleus of comet 67P/Churyumov–Gerasimenko (that was the destination of the European Space Agency's Rosetta mission) is about 4km in diameter while nucleus of comet Hale–Bopp was about 60±20 kilometres in diameter. According to these data and with a reasonable degree of certainty, C/2014 UN271 it’s the biggest comet that we’ve ever seen!

Despite some exceptional features displayed by this comet, its considerable distance to perihelion should limit the peak magnitude to fairly modest values. Anyway, as always with comets, the future magnitudes reported here are only indicative. Below you can see a graph generated using the software Orbitas and showing the predicted magnitude (in red) versus its distance from the Sun.


We have been able to image this special comet on 2021 June 27 at 10UT from X02 (Telescope Live, Chile) with our CHI-1 telescope that is a 0.61-m f/6.5 astrograph + CCD. Stacking of 13 unfiltered exposures, 240 seconds each, clearly shows the coma developed by this object (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori). (click on the images below for a bigger version; made with TYCHO software by D. Parrott).

 

 

We had the pleasure of seeing our image featured in the article dedicated to this comet by the New York Times and written by science writer  R. G. Andrews.

Below an image from the Dark Energy Survey (DES) composed of some of the discovery exposures showing Comet Bernardinelli-Bernstein collected by the 570-megapixel Dark Energy Camera (DECam) mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile. These images show the comet in October 2017, when it was 25 au away from the Sun. (Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA/P. Bernardinelli & G. Bernstein (UPenn)/DESI Legacy Imaging Surveys. Acknowledgments: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), M. Zamani (NSF’s NOIRLab) & J. Miller (NSF’s NOIRLab))

There is no doubt that this comet will be one of the most observed by astronomers for years to come.

by Ernesto Guido