2018 DO4 è una cometa

Bel successo italiano sull'asteride 2018 DO4, Roberto Haver ha segnalato sulla mailist della Sezione Asteroidi la probabile presenza di una chioma. Buzzi conferma ( News UAI )
e cosi esce la

CBET 4675: COMET C/2018 DO_4

An apparently asteroidal object discovered on CCD images taken last
year
by G. J. Leonard with the Mount Lemmon Survey's 1.5-m reflector (and
announced
with minor-planet designation on MPEC 2018-F13) has been found to show
cometary activity now near perihelion.  The discovery astrometry is
tabulated
below; follow-up observations appeared on MPEC 2018-Y11.

     2018 UT             R.A. (2000) Decl.       Mag.   Observer
     Feb. 25.31328   12 43 55.51   +19 42 43.9   20.6   Leonard
          25.31843   12 43 55.22   +19 42 46.7   21.3     "
          25.32358   12 43 54.90   +19 42 50.0   21.3     "
          25.32874   12 43 54.62   +19 42 53.7   21.0     "

CCD astrometrists elsewhere have reported cometary appearance in 2018 DO4.
L. Buzzi, Varese, Italy, reports that stacked images taken with his 0.60-m
f/4.6 reflector on Aug. 30.1 UT show a 15" coma and a tail at least 30" long
in p.a. 282 degrees; the magnitude was measured as 16.6.  Buzzi adds that he
measured ninety stacked 15-s images obtained by R. Holmes with a 0.76-m f/3
astrograph at Westfield, IL, USA, on Sept. 4.4, which show an elongated coma
and a broad, curved tail 50" long in p.a. 285 deg; the magnitude was given
as
17.2-17.8.  Buzzi further comments on images taken with his 0.60-m reflector
on Sept. 17.1 that show a strongly condensed coma 10" wide (red mag 16.8)
with a broad, fan-shaped tail at least 45" long centered in p.a. 294 deg.
M. Micheli reports that images taken on Sept. 2.63 and 3.63 by K. J. Meech
and J. Kleyna with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea
show a broad tail about 25" long in p.a. about 300 degrees.  W. Ryan notes
that his images taken on Sept. 3.4 with the Magdalena Ridge Observatory
2.4-m reflector show a bright coma with distinct tail in p.a. about 290
degrees.  H. Sato, Tokyo, Japan, writes that six stacked 60-s exposures
taken
on Sept. 4.47 with a 0.43-m f/6.8 astrograph near Mayhill, NM, USA, show a
condensed coma 20" in diameter with a fan-like tail 40" long toward p.a.
260-300 degrees; the magnitude was 16.1 as measured within a circular
aperture of radius 11".5.
     Twelve co-added 40-s unfiltered exposures taken by T. Chen with a 0.3-m
f/7.2 reflector at Ngari, Tibet, China, in the course of the BIST survey
(cf. CBET 4629) around Sept. 4.89 (and measured by D. W. E. Green) show a
well-condensed coma of size about 7" in 3" seeing, with a faint tail perhaps
15" long in p.a. 267 degrees; the total magnitude was 17.4 in an aperture of
diameter 10".  Twenty-four stacked 40-s BIST exposures on Sept. 5.9 show a
well-condensed coma of size 8"-10" in 2".6 seeing, with a faint tail perhaps
15" long fanned in p.a. 251-314 degrees; the total magnitude was 17.0 in an
aperture of diameter 12".  Fifteen stacked BIST exposures taken on Sept. 6.9
show a well-condensed coma of size about 7" in 3" seeing, with a faint but
obvious fan tail up to 25" long centered at p.a. about 275 degrees; the
total
unfiltered magnitude was 17.0 in an aperture of diameter 30".  Thirty-one
stacked BIST exposures taken on Sept. 7.9 show a well-condensed coma of size
about 8", with a faint but obvious fan tail up to 15" long centered at p.a.
about 275 degrees (fan perhaps 80 degrees wide); the total unfiltered
magnitude was 17.1 in an aperture of diameter 20".  Nine stacked BIST
exposures taken on Sept. 8.8 show a condensed coma of size about 9" that is
elongated along p.a. 345/175 degrees, with a faint-but-obvious diffuse tail
up perhaps 20" long centered at p.a. about 280 degrees; the total magnitude
was 16.4 in an aperture of diameter 20".  Thirty-three stacked BIST
exposures taken on Sept. 9.9 show a condensed coma of diameter about 10" (in
2".6 seeing) with a faint-but-obvious, diffuse fan tail perhaps 22" long
centered at p.a. about 270 degrees; the total magnitude was 17.3 in an
aperture of diameter 14".
     R. Haver writes that twenty-four 90-s exposures taken on Sept. 8.11
with
a 0.37-m f/7 Cassegrain reflector at Frasso Sabino, Italy, shows a coma of
diameter 6".5 and magnitude 16.0; there was a slightly curved fan tail about
45" long in p.a. 287 degrees.  Haver's follow-up images on Oct. 6.16 show
total red mag 16.5 with a coma diamete of 10".7 and a curved tail 44" long
in p.a. 292 degrees.  S. Nakano, Sumoto, Japan, forwards a report by Y.
Mizuno (Kani, Japan) whose CCD images taken on Sept. 9.73 show magnitude
16.8 and a tail 0.5 degree long in p.a. 270 degrees.  F. Kugel reports that
unfiltered CCD images taken on Sept. 12.15 by C. Rinner and himself with a
0.4-m f/2.8 reflector at Dauban, France, show a condensed coma and a broad
tail in p.a. 276 deg.  Unfiltered images taken by J.-F. Soulier taken on
Sept. 16.1 with a 0.30-m f/3.8 Newtonian reflector at Maisoncelles, France,
show a coma about 15" in size and a tail about 25" long in p.a. 270-300 deg;
the magnitude was 16.7 in an aperture of radius 6".5.  Soulier adds that
exposures taken on Sept. 19.1 show a coma of size about 19" and a tail about
25" long in p.a. 210-300 degrees; the magnitude was about 16.7 in an
aperture
of radius 6".5.  Twenty stacked 30-s unfiltered exposures taken remotely on
Sept. 29.34 by E. Guido, Castellammare di Stabia, Italy, with a 0.6-m f/6.5
astrograph at El Sauce Observatory in Chile show a coma nearly 20" in
diameter with a central condensation and a diffuse fan-shaped tail about 45"
long toward p.a. 275 degrees.  V. Rumyantsev reports that images taken on
Oct. 2.035 UT with the 2.6-m Shajn telescope of Crimean Astrophysical
Observatory at Nauchny, Crimea, show a bright 14" coma of red mag 17.3 and a
60" tail toward p.a. about 290 deg.  Sixty stacked 60-s exposures taken by
P. Bacci, M. Maestripieri, and M. Facchini with a 0.60-m f/4 reflector at
San Marcello Pistoiese, Italy, on Oct. 6.1 show a coma with red mag 15.8 and
a tail 1'10" long in p.a. 302 degrees; they have posted a stacked image of
the comet at URL http://backman.altervista.org/Aimg/2018DO4_01_sm.jpg.
     Additional astrometry has been published on MPEC 2019-T99.  The
following
orbital elements by S. Nakano, Sumoto, Japan, are from 374 observations
spanning 2016 Apr. 5-2019 Oct. 2 (mean residual 0".39).  The comet passed
2.87 AU from Jupiter on 2017 May 28 UT; its next return to perihelion is
predicted to be on 2147 October 10.  No additional observations have been
identified in archival astrometry.

                    Epoch = 2019 Aug. 25.0 TT
     T = 2019 Aug. 18.40490 TT        Peri. = 175.97274
     e = 0.9069557                    Node  = 251.13292 2000.0
     q = 2.4059613 AU                 Incl. = 160.47470
       a = 25.8582318 AU   n = 0.00749559   P = 131.5 years

The following ephemeris by the undersigned from the above orbital elements
uses power-law photometric parameters H = 12.5 and 2.5n = 6 for the
predicted
magnitudes.

2I C/2019 Q4, la cometa interstellare.

Dall'osservatorio di San Marcello abbiamo confermato la prima cometa insterstellare mai scoperta.

(18303) 1980 PU è Binario

Grande soddisfazine nell'aver contribuito alla scoperta di questo nuovo asteroide binario. dall'osservtorio di San Marcello, comìne Martina Maestripeiri, sono state ottenute due sessioni sservative. Era richiesta una precisione di 0.02 mag ed almeno 4 ore conseguitve di osservazione.

e cosi il 10 ottobre esce la
CBET 4676: (18303)1980 PU Binary
 V. Benishek, Belgrade Astronomical Observatory; P. Pravec and P.
Kusnirak, Ondrejov Observatory; R. Durkee, Shed of Science South
Observatory,
Pontotoc, TX, U.S.A.; D. Pray, Sugarloaf Mountain Observatory, South
Deerfield, MA, U.S.A.; V. Chiorny and O. Mikhalchenko, Kharkiv Observatory;
M. Husarik and M. Pikler, Skalnate Pleso Observatory; J. Oey, Blue Mountains
Observatory, Leura, NSW, Australia; P. Bacci and M. Maestripieri,
Astronomical Observatory, San Marcello Pistoiese, Italy; and A. Aznar, Isaac
Aznar Observatory, Alcublas, Valencia, Spain, report that photometric
observations taken with a 0.35-m telescope at the Sopot Observatory in
Serbia, a 0.50-m telescope at the Shed of Science South Observatory, a
0.50-m telescope at the Sugarloaf Mountain Observatory, a 0.70-m telescope
at the Chuguev station of the Kharkiv Observatory in Ukraine, a 0.61-m
telescope at the Skalnate Pleso Observatory, a 0.35-m telescope at the Blue
Mountains Observatory, a 0.60-m telescope at the San Marcello Pistoiese
Observatory, and a 0.35-m telescope at the Isaac Aznar Observatory during
Aug. 10-Oct. 2 reveal that minor planet (18303) is a binary system with an
orbital period of 12.270 +/- 0.003 hr.  The primary shows a period of
2.72627 +/- 0.00010 hr and has a lightcurve amplitude of 0.10 magnitude at
solar phases 4-14 degrees, suggesting a nearly spheroidal shape.  Mutual
eclipse/occultation events that are 0.05 to 0.12 magnitude deep indicate
a secondary-to-primary mean-diameter ratio of 0.24 +/- 0.03.

1980 PU, 18303 Un nuovo Asteroide Binario

Grazie ad una collaborazione internazionale, alla quale ha partecipato anche un osservatorio della Sezione Asteroidi dell’UAI è stato possibile determinare che l’asteroide 18303 è binario.

Scoperto dall’astronoma Zdeňka Vávrová il 06 agosto del 1980 dall’osservatorio di Klet nella repubblica Ceca, 1980 PU (questa la sua prima designazione) fa parte della fascia principale degli asteroidi, ruota intorno al Sole in 1.4 anni con un’eccentricità di 0.2 ed inclinazione di 4.26°.

Fig.1 – Elementi orbitali dell’asteroide (18303) 1980 PU tratte dal JPL

Dall’Osservatorio della Montagna Pistoiese, gestito dal GAMP – Gruppo Astrofili Montagna Pistoiese – Paolo Bacci e Martina Maestripieri , hanno effettuato due sessioni osservative nelle notti del 30 agosto e 4 settembre 2019. Per aderire alla campagna osservativa coordinata da Petr Pravec dell’Astronomical Institute of the Czech Academy of Sciences di Praga era necessario effettuare almeno 4 ore consecutive di osservazione con un errore di +/-0.02 mag. Per un oggetto che aveva una luminosità di 16.2 mag.

Dall’osservatorio di San Marcello ( codice MPC104) utilizzando il telescopi da 0.60-m F/4 con abbinata CCD 1024×1024 con un FOV di 35’x35’ ed una risoluzione di 2”/pixel venivano acquisite immagini con esposizione di 5 minuti ciascuna. Dopo aver applicato il dark e flat, le immagini venivano processate con il sofwtare Canopous per determinare la curva di luce.

Fig. 2 Curva di Luce ottenuta dall’osservatorio 104 San Marcello.
Si nota (punti Blu) che è stato ripreso l’evento secondario.

Anche grazie ai dati ottenuti dall’osservatorio italiano è stato possibile determinare il periodo di rotazione del secondario in 12.270 +/- 0.003 h, mentre 18303 ruota in 2.72627 +/- 0.00010 h.

Il 10 ottobre esce la Electronic Telegram No.4676 del Central Bureau for Astronomical Telegrams del Harvard University di Cambridge U.S.A. con la quale viene annunciata la scoperta.

(18303) 1980 PU
     V. Benishek, Belgrade Astronomical Observatory; P. Pravec and P.
Kusnirak, Ondrejov Observatory; R. Durkee, Shed of Science South
Observatory, Pontotoc, TX, U.S.A.; D. Pray, Sugarloaf Mountain Observatory, South
Deerfield, MA, U.S.A.; V. Chiorny and O. Mikhalchenko, Kharkiv Observatory;
M. Husarik and M. Pikler, Skalnate Pleso Observatory; J. Oey, Blue Mountains
Observatory, Leura, NSW, Australia; P. Bacci and M. Maestripieri,
Astronomical Observatory, San Marcello Pistoiese, Italy; and A. Aznar, Isaac
Aznar Observatory, Alcublas, Valencia, Spain, report that photometric
observations taken with a 0.35-m telescope at the Sopot Observatory in
Serbia, a 0.50-m telescope at the Shed of Science South Observatory, a
0.50-m telescope at the Sugarloaf Mountain Observatory, a 0.70-m telescope
at the Chuguev station of the Kharkiv Observatory in Ukraine, a 0.61-m
telescope at the Skalnate Pleso Observatory, a 0.35-m telescope at the Blue
Mountains Observatory, a 0.60-m telescope at the San Marcello Pistoiese
Observatory, and a 0.35-m telescope at the Isaac Aznar Observatory during
Aug. 10-Oct. 2 reveal that minor planet (18303) is a binary system with an
orbital period of 12.270 +/- 0.003 hr.  The primary shows a period of
2.72627 +/- 0.00010 hr and has a lightcurve amplitude of 0.10 magnitude at
solar phases 4-14 degrees, suggesting a nearly spheroidal shape.  Mutual
eclipse/occultation events that are 0.05 to 0.12 magnitude deep indicate
a secondary-to-primary mean-diameter ratio of 0.24 +/- 0.03.