Tuesday, October 27, 2020

Discovery of a Nova in M31 - AT2020xyv

A new M31 nova candidate was independently discovered on 2020 Oct. 21.741 (by K. Hornoch and H. Kucakova), on 2020 Oct. 21.92 UT (by A. Catapano, L. Izzo, E. Guido, A. Noschese, F. Coccia, L. D'Avino) and 2020 Oct. 22.550 UT (by M. Zhang and X. Gao) and designated as PNV J00423733+4120519 = AT2020xyv = M31N 2020-10e (ATel #14114). This possible nova was first reported on 2020 Oct. 22.56 by Zhang and Gao as a new source of G ~ 16.9 mag on CBAT "Transient Object Followup Reports" (TOCP PNV J00423733+4120519).

Spectroscopic observations of AT2020xyv (PNVJ00423733+4120519) were obtained with the 3.58m TNG telescope equipped with LRS at Observatorio del Roque de los Muchachos in La Palma (Spain) by L. Izzo et al. (ATel #14116). Observations started on October 24 at 01:12:54 UT and they consisted of three exposures of 600s each: "The combined spectrum (covering the range 3,500-8,000 AA, resolving power R = 585) shows bright emission lines of H-alpha and H-beta, the presence of O I 7773 and Fe II lines (multiplet 42 and blended multiplets 37 and 38). From the H-alpha profile, we measure an FWHM of ~4,000 km/s. H-alpha and H-beta lines show P-Cygni profiles (although not prominent) with a minimum at ~ -2,800 km/s. The spectrum is then consistent with a broad-line Fe IIb Classical Nova in M31".

On 2020 Oct. 22.6, we reported on the TOCP our independent discovery of this nova in M31 on a 180-s R-band CCD frame taken on 2020 Oct. 21.92 UT with the 0.5 m f/8 Ritchey Chretien + CCD FLI PL4240 at MPC Code L07 (Osservatorio Salvatore di Giacomo, Agerola, ITALY) at the following coordinates:

R.A. = 00 42 37.33, Decl.= +41 20 52.1 (equinox 2000.0; Gaia DR2).

Our discovery image (click on it for a bigger version):


We have obtained daily BVR photometric observations of this nova with the 0.5m telescope at the Osservatorio Salvatore di Giacomo, Agerola (Italy). We have first detected the nova in BVR images obtained on October 21.92 as a new object in M31 with a magnitude V = 17.70 +- 0.05 mag. The most recent observations of this nova were obtained by us on October 23.85, and we report the following magnitudes: B = 19.39 +- 0.32 mag, V = 18.11 +- 0.12 mag, R = 19.06 +- 0.15 mag.  
 

Nothing is visible at this position on our archival images taken on 2020, October 20.83 (limiting B-mag 21). Zhang and Gao reported an upper limits (G > 20.5 mag) in images obtained on October 21.55. Kucacova et al. reported in ATel #14114 the first detection of this nova in images obtained on October 21.74 as an object with R = 18.1 +- 0.2. 

On ATel #14117, Hornoch et al. reported the identification of AT2020xyv as a likely recurrence of M31N 1998-10b, and thus a recurrent nova in M31. Using the updated online catalogue of all historical optical novae and nova candidates in M31 (Pietsch et al. 2007), they found that the measured position of nova AT2020xyv = PNV J00423733+4120519 = M31N 2020-10e "is very close (1.2") to that reported for a nova, M31N 1998-10b, previously discovered as part of the Research-Based Science Education (RBSE) project (Rector et al. 1999). Based on the position of the nova, which is located at an isophotal radius of 8.2' from the center of M31, we compute the probability of a chance positional coincidence between these two novae to be less than 0.01%"


by A. Catapano, L. Izzo, E. Guido, A. Noschese, F. Coccia, L. D'Avino (OASDG; AstroCampania)

Monday, September 21, 2020

New Comet C/2020 S3 (Erasmus)

CBET 4885 & MPEC 2020-S119, issued on 2020, September 20, announce the discovery of a comet (magnitude ~18.5) by Nicolas Erasmus (South African Astronomical Observatory), in four 30-s CCD images taken in 5" seeing on Sept. 17.6 UT with a 0.5-m f/2 Schmidt reflector at Mauna Loa, Hawaii, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program. The new comet has been designated C/2020 S3 (Erasmus).

We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 151 unfiltered exposures, 30 seconds each, obtained remotely on 2020, September 19.1 from L07 (Osservatorio Salvatore di Giacomo, Agerola) through a 0.5 m f/8 Ritchey Chretien + CCD FLI PL4240, shows that this object is a comet with a diffuse coma about 20" in diameter.

Our confirmation image (click on it for a bigger version)


MPEC 2020-S119, assigns the following preliminary parabolic orbital elements to comet C/2020 S3 (Erasmus): T 2020 Dec. 13.24; e= 1.0; Peri. =  349.09; q = 0.4;  Incl.= 19.79

While the orbit is still very preliminary, there is a chance that this comet will pass through the SOHO C3 fov starting from about December 16, 2020 (the visibility on C3 will depend also on the magnitude this comet will reach around perihelion; a vmag at least +8 is required to be visible in C3). Below you can see a graph showing part of the possible C3 passage (from Dec. 16 to Dec. 21, 2020; click on it for a bigger version). At the following link is available the animation, just press the play button to see it.

 

Made with Orbitsimulator


by Ernesto Guido

Monday, August 3, 2020

New Comet C/2020 O2 (Amaral)

CBET 4822 & MPEC 2020-P10, issued on 2020, August 02, announce the discovery of a comet (magnitude ~18) by Leonardo S. Amaral (Rio de Janeiro, Brazil) on three 60-s CCD exposures taken on July 23 with a 0.3-m f/4 reflector. The new comet has been designated C/2020 O2 (Amaral).

We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 16 unfiltered exposures, 90 seconds each, obtained remotely on 2020, July 27.05 from X02 (Telescope Live, Chile) through a 0.6-m f/6.5 astrograph + CCD, shows that this object is a comet with a diffuse coma about 8" in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Our confirmation image (click on it for a bigger version)



Discovery image

Credit: L. S. Amaral (OCA)


MPEC 2020-P10, assigns the following preliminary parabolic orbital elements to comet C/2020 O2 (Amaral): T 2021 Aug. 23.84; e= 1.0; Peri. =  9.39; q = 4.90;  Incl.= 71.89

Congrats to Leonardo Scanferla Amaral (Observatório Campo dos Amarais, OCA) for this discovery! This is the fourth amateur comet discovery of 2020.

by Ernesto Guido

Friday, July 17, 2020

BRIGHT NOVA RETICULI 2020

Following the posting on the CBET 4811 & 4812 about the NOVA RETICULI 2020 we performed some follow-up of this object through a TEL 0.1-m f/3.6 astrograph + CCD located in the Heaven's Mirror Observatory, Australia (MPC code Q56) and operated by Telescope Live network.

On images taken on July 16.82, 2020 we can confirm the presence of an optical counterpart (with R-filtered magnitude about +4.5; B-filtered magn. +5.6; V-filtered magn. +5.6) at coordinates:

R.A. = 03 58 29.61, Decl.= -54 46 39.8

(equinox 2000.0; Gaia DR2 catalogue reference stars for the astrometry).

This transient was discovered by Robert H. McNaught (Coonabarabran, NSW, Australia) as an apparent 5th-magnitude nova on CCD images obtained on July 15.590 UT with a Canon 6D camera and an 8-mm-f.l. f/2.8 lens (at ISO 800). The position is very close to an object listed as "MGAB-V207" in the AAVSO's VSX online database (which gives position R.A. = 3h58m29s.55, Decl. = -54d46'41".2, equinox J2000.0, which calls it a novalike "VY Scl"-type variable with V magnitude range 15.8-18.0).

Spectroscopy by E. Aydi et al. (ATel #13867) using the High Resolution Spectrograph (HRS) mounted on the 11m Southern African Large Telescope as part of the SALT Large Science Program on Transients shows a spectrum that resembles that of a classical nova, likely after optical peak. Also, R. Kaufman (Bright, VIC, Australia) reports a low-resolution spectrum obtained by him on 2020 Jul. 16.62 UT (with a Canon 800D camera + 200-mm-f.l. f/3.5 lens) indicates the object to be a "Fe II-type" classical nova.

According to ATel #13868 "the positional coincidence of the optical/gamma-ray transient with the previously known VY Scl-type cataclysmic variable (d = 2.7 kpc from Gaia DR2; Bailer-Jones et al. 2018) suggests that the transient is a Galactic nova, which was confirmed with SALT spectroscopy (ATel #13867). It is only the third time that a classical nova eruption is observed in a previously known white dwarf hosting binary after V407 Cyg (ATel #2487) and V392 Per (ATel #11590), which were also detected by Fermi-LAT."

According to Cbet 4812 "the following pre-discovery V magnitudes from all-sky video images taken by M. A. Phillips at the Edward Pigot Seismic Observatory, Coonabarabran, using a ZWO ASI178MC-COOL color CMOS camera and a 1.4-mm-f.l. f/1.8 fish-eye lens: July 6.81, [6.0; 7.79, [5.5; 8.78, 5.4; 11.76, 3.7; 12.8, 3.8; 13.83, 4.0; 14.8, 4.4; 15.8, 4.7.  No variability was seen on single nights.  Further CCD magnitudes reported by McNaught from his images:  June 30.727, [9.8; July 1.763, [9.9; 2.826, [8.8; 15.747, 5.1; 15.785, 5.1; 15.804, 5.1. 

P. Schmeer, Bischmisheim, Germany, reports the following g magnitudes for the nova from the ASAS-SN Sky Patrol:  July 2.183, 16.6; 2.186, 16.3; 4.189, 15.5; 8.173, 6.8.  Schmeer adds that no previous outbursts or eruptions were recorded in ASAS-SN patrol images since 2014 June 18."


Below our confirmation image. Click on the image for a bigger version: 



An animation showing a comparison between my image and the archive POSS2/UKSTU Red plate (1993-12-17). 



by  Ernesto Guido, Marco Rocchetto & Adriano Valvasori

Wednesday, June 17, 2020

New Comet C/2020 K8 (CATALINA-ATLAS)

CBET 4796 & MPEC 2020-L46, issued on 2020, June 12, announce the independent discovery of a comet (magnitude ~19) of an apparently asteroidal object made on CCD images taken with the 0.68-m Schmidt telescope of the Catalina Sky Survey (on May 25, 28, and 29) and the 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii, in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program (on June 7). Then on June 8, R. Weryk reported the linkage of all of these tracklets, suggesting it might possibly be a comet based upon the astrometry. The object has been found to show cometary appearance subsequently by numerous CCD astrometrists at other observing sites after the object was posted on the Minor Planet Center's PCCP webpage. The new comet has been designated C/2020 K8 (CATALINA-ATLAS).

We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 29 unfiltered exposures, 60 seconds each, obtained remotely on 2020, June 09.4 from X02 (Telescope Live, Chile) through a 0.6-m f/6.5 astrograph + CCD, shows that this object is a comet with a diffuse irregular coma about 10" in diameter (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini).

Stacking of 24 unfiltered exposures, 57 seconds each, obtained remotely on 2020, June 10.4 from U69 (iTelescope, Auberry California) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a diffuse coma about 15" in diameter slightly elongated toward PA 358 (Observers A. Valvasori, E. Guido).


Our confirmation images (click here for a bigger version)






MPEC 2020-L46, assigns the following preliminary parabolic elements to comet C/2020 K8 (CATALINA-ATLAS): T 2020 Sept. 14.49; e= 1.0; Peri. =  260.11; q = 0.47;  Incl.= 31.42

by Ernesto Guido

Wednesday, June 3, 2020

New Comet C/2020 K7 (PANSTARRS)

CBET 4790 & MPEC 2020-L09, issued on 2020, June 02, announce the discovery of a comet (magnitude ~20) in four 45-s w-band CCD images obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala. The new comet has been designated C/2020 K7 (PANSTARRS).

We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 8 unfiltered exposures, 180 seconds each, obtained remotely on 2020, June 02.2 from X02 (Telescope Live, Chile) through a 0.6-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 6" in diameter and a tail 3" long in PA 306 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini).

Our confirmation image (click here for a bigger version)



MPEC 2020-L09, assigns the following preliminary parabolic orbital elements to comet C/2020 K7 (PANSTARRS): T 2021 Oct. 5.30; e= 1.0; Peri. =  60.84; q = 5.64;  Incl.= 34.55


by Ernesto Guido

Monday, May 25, 2020

New Comet C/2020 K3 (Leonard)

CBET 4782 & MPEC 2020-K159, issued on 2020, May 25, announce the discovery of a comet (magnitude ~18) by G. J. Leonard on images taken on May 22 UT with the Catalina Sky Survey's 0.68-m Schmidt reflector. The new comet has been designated C/2020 K3 (Leonard).

We performed follow-up measurements of this object while it was still on the PCCP webpage.

Stacking of 20 unfiltered exposures, 55 seconds each, obtained remotely on 2020, May 23.4 from H06 (iTelescope network)  through a 0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer, shows that this object is a comet with a diffuse irregular coma about 15" in diameter.

Our confirmation image (click here for a bigger version)



MPEC 2020-K159, assigns the following preliminary parabolic orbital elements to comet C/2020 K3 (Leonard): T 2020 June 01.00; e= 1.0; Peri. =  64.49; q = 1.58;  Incl.= 129.01

By Ernesto Guido & Adriano Valvasori