Il bolide del 13 agosto 2017

Molto probabilmente nessuno avrà potuto beneficiare dello spettacolo che avrebbe offerto il bolide che ha attraversato  l’atmosfera sopra le nostre teste il 13 di agosto in quanto era pieno giorno  e la luce del Sole, molto intensa a quell’ora, ha sicuramente offuscato quella emessa dal meteoroide.

Per “bolide” s’intende una meteora molto luminosa, più luminosa del pianeta Venere, e quindi molto spettacolare quando appare nel cielo scuro della notte.

Ma se nulla poteva l’occhio nudo , il fenomeno non è passato inosservato alla nostra stazione per radio meteore che era vigile ed attenta in quanto acquisisce in continuo i segnali radio riflessi dalla scia delle meteore e quindi ha registrato la sua “eco”.

La foto mostra la traccia radio registrata dalla nostra stazione per “radio meteore” del bolide apparso nei nostri cieli il 13 di agosto alle 12.22 circa di TU. La traccia dura più di un minuto. Se la “breccola cosmica” avesse ritardato di qualche ora ad impattare contro la nostra atmosfera ci sarebbe stato uno spettacolo pirotecnico non indifferente.

Dal momento che è impossibile in queste condizioni calcolare l’orbita di questo meteoroide non sappiamo a quale cometa o asteroide associarlo. Ad ogni modo possiamo ragionevolmente ipotizzare che appartenga allo sciame meteorico delle “perseidi” sia in quanto coincidente appieno col periodo di massima osservazione di questo sciame meteorico e sia perché a questo sciame è associato il maggior numero di bolidi osservabili.

Quindi non potendo calcolare una traiettoria del bolide, nemmeno possiamo tentare un calcolo di un eventuale impatto col suolo anche se quasi sicuramente il meteoride si sarà completamente volatilizzato in bassa atmosfera. Molto probabilmente il suo pulviscolo residuo dopo essere stato trascinato dai venti in quota avrà raggiunto il suolo terrestre posandosi delicatamente chissà dove…

 

 

Maurizio Scardella
Responsabile Gruppo Ricerca ATA

P.S.
Un doveroso ringraziamento ai Soci Fernado Pierri, Samuele Piscitello e Simone Nodari per l’attenta e accurata gestione tecnica della stazione radio meteore dell’ATA.

Traccia radar lasciata dal meteoroide registrata alla stazione radiometeore ATA

 

Annunci

Calcolato il periodo di rotazione di (703) Noemi

Lorenzo Franco Balzaretto Observatory (A81), Rome, ITALY lor_franco@libero.it

Maurizio Scardella, Angelo Tomassini,
Francesco Franceschini, Fernando Pierri
Osservatorio Astronomico “F. Fuligni” (D06)
Via Lazio 14, 00040 Rocca di Papa (RM), ITALY

Alessandro Marchini
Astronomical Observatory, DSFTA – University of Siena (K54)
Via Roma 56, 53100 – Siena, ITALY
(Received: 2017 Apr 5)

Collaborative lightcurve photometry observations of
main-belt asteroid 703 Noemi were made over 16 nights
in 2016 November thru 2017 January. The resulting
synodic rotation period is 200 ± 1 h, amplitude 0.62 ±
0.10 mag, HR = 12.24 ± 0.12 and GR = 0.16 ± 0.10.

The main-belt asteroid 703 Noemi was discovered on 1910 October 3 by J. Palisa at Vienna. The primary orbital elements are  a = 2.175 AU, e = 0.138, and i = 2.46°. Its absolute magnitude is H = 12.5 (JPL, 2017). The NEOWISE survey (Nugent et al., 2016) used a value of 12.70 to find a diameter of D = 9.85 ± 1.42 km. The gives an optical albedo of pV = 0.19 ± 0.10. CCD photometric observations were made over 16 nights from 2016 November 15 to 2017 January 29 at the Balzaretto Observatory (A81), Fuligni Observatory, and the DSFTA Observatory (DSFTA, 2017) using the instrumentation described in Table I.

Data processing and analysis were done at the Balzaretto Observatory with MPO Canopus (Warner, 2016). All the images, acquired with clear-filter, were calibrated with dark and flat frames and converted to the Cousins-R magnitudes using solar colored field stars from CMC15 catalogue (VizieR, 2014) by the relationship R = r´ – 0.22 (Dymock and Miles, 2009). No offset adjustment was applied to the lightcurves. The period analysis shows a bimodal solution for P = 200 ± 1 hours and amplitude A = 0.62 ± 0.10 magnitudes.

The absolute magnitude H (R-band) and slope parameter G were found using the H-G Calculator function of MPO Canopus. For each lightcurve the average R mag was measured removing the rotational effects, using a Fourier fit model (Buchheim, 2010). We found H (R-band) = 12.24 ± 0.12 mag, G = 0.16 ± 0.10. For 703 Noemi, the taxonomic class and the color index are unknown. We assume it is S-type asteroid, according to SMASSII taxonomic class distribution vs semi-major axis (Bus and Binzel, 2002) with a color index V-R = 0.49 ± 0.05 (Shevchenko and Lupishko, 1998). We then derive H = 12.73 ± 0.13, close to the H = 12.7 listed by Nugent et al. (2016).

Observatory            Telescope,                   CCD              Exp (s)

Balzaretto (A81)- 0.20-m f/5.5          SCT SBIG ST7xme         420

Fuligni (D06)- 0.35-m f/10                 SCT SBIG ST8-xe            120

DSFTA (K54)- 0.30-m f/5.6 MCT   SBIG STL-6303e (2×2)    300

Table II. Observing Instrumentation. SCT: Schmidt-Cassegrain Telescope, MCT: Maksutov-Cassegrain Telescope.

References

Bus S.J., Binzel R.P. (2002). “Phase II of the Small Main-Belt Asteroid Spectroscopic Survey – A Feature-Based Taxonomy.Icarus 158, 146-177.

DSFTA (2017). Dipartimento di Scienze Fisiche, della Terra e dell’Ambiente, University of Siena – Astronomical Observatory. https://www.dsfta.unisi.it/en/department/sciencemuseums/astronomical-observatory

Dymock, R., Miles, R. (2009). “A method for determining the V magnitude of asteroids from CCD images.” J. Br. Astron. Assoc. 119, 149-156.

Harris, A.W., Young, J.W., Scaltriti, F., Zappala, V. (1984). “Lightcurves and phase relations of the asteroids 82 Alkmene and 444 Gyptis.” Icarus 57, 251-258.

JPL (2017). Small-Body Database Browser. http://ssd.jpl.nasa.gov/sbdb.cgi#top Nugent, C.R., Mainzer, A., Bauer, J., Cutri, R.M., Kramer, E.A., Grav, T., Masiero, J., Sonnett, S., Wright, E.L. (2016).

“NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos.” Astron. J. 152, A63.

Shevchenko V.G., Lupishko D.F. (1998). “Optical properties of Asteroids from Photometric Data.” Solar System Research 32, 220-232.

VizieR (2014). http://vizier.u-strasbg.fr/viz-bin/VizieR.

Warner, B.D. (2016). MPO Software, MPO Canopus v10.7.7.0.

Bdw Publishing. http://minorplanetobserver.com

 

Lo sciame delle K-serpentidi

La stazione ricevente  dedicata alle radiometeore installata presso l’Osservatorio “F. Fuligni”, in cui è presente un’antenna capace di catturare le onde elettromagnetiche provocate dall’attraversamento di meteoriti nell’alta atmosfera, ha captato durante il mese di aprile lo sciame delle “Kappa Serpentidi”. Esso fa parte del sistema complesso delle Virginidi, forse associato alla cometa 1914 IV.

Prendendo spunto dalle previsioni di sciami meteorici del sito dell’U.A.I., si è appreso che le KSer avrebbero attraversato l’atmosfera nel periodo compreso tra il 1 e il 12 aprile, con maggiore attività verso le ore 5 UTC, specie nelle notti del 4 e 5 aprile.

La registrazione dei dati, ottenuta con l’ausilio di Spectrumlab, ha permesso di costruire tabella e grafici inerenti lo sciame.

La tabella presenta il conteggio delle radiometeore per giorno e per ora (sia UTC, che legale) e con essa è stato possibile elaborare 3 grafici: il primo riporta il numero totale di radiometeore conteggiate al giorno per tutto il periodo dello sciame, il secondo mostra i dati completi, mentre il terzo è l’ingrandimento del periodo prossimo al picco. Sia il secondo che il terzo grafico sono stati costruiti seguendo l’orario di Greenwich.

Degno di nota è il dato registrato alle ore 5 UTC del  4 aprile che riporta il risultato della massima ricezione di eventi meteorici.

Mariangela Monti

Gruppo Ricerca ATA

(3841) Dicicco

 

3841 DICICCO: A BINARY ASTEROID

Lorenzo Franco
Balzaretto Observatory (A81), Rome, ITALY

Alessandro Marchini
Astronomical Observatory, University of Siena (K54)
via Roma 56, 53100 Siena, ITALY

Carolyn E. Odden
Phillips Academy Observatory (I12)
Andover MA USA

Petr Pravec
Ondrejov Observatory
Ondrejov, CZECH REPUBLIC

Maurizio Scardella, Angelo Tomassini
Osservatorio Astronomico “F. Fuligni” (D06)
Via Lazio 14, 00040 Rocca di Papa (RM), ITALY

Initial observations of 3841 Dicicco indicated a period of 3.6 hours with three nights being anomalously low over part of the period. Further analysis showed that 3841 is a binary asteroid with a primary period of 3.5950 ± 0.0001 h with an amplitude of 0.19 mag and a secondary period of 21.641 ± 0.002 h with an amplitude of 0.19 mag. Both the primary eclipse and secondary eclipses were visible. We also estimate the H and G parameters to be H = 13.63 ± 0.04, G = 0.15 ± 0.05.

The S-type asteroid (Bus and Binzel, 2002) 3841 Dicicco was observed on 18 nights from 2014 Nov 21 through 2015 Jan 11. Starting from the first sessions, we noticed some anomalous attenuations in the lightcurves that made us suspect they were due to eclipse and/or occultation events (Figure 1, 2). Five observatories were in the campaign to confirm the initial observations. Table I lists the observers and equipment they used.

Observers Telescope CCD
Franco

(A81)

Klinglesmith(719)

Marchini (K54)

Odden (I12)

Scardella,Tomassini (D06)

0.2-m f/5.5 SCT

0.35-m f/10 SCT

0.30-m f/5.6 MCT

0.4-m f/8 R-C

0.35-m f/10 SCT

SBIG ST-7XME SBIG

STL-1001E SBIG

ST-10XME SBIG

STL-6303E (bin 2×2) Apogee CCD

SBIG ST-8XE

Table 1. Observers and Equipment. SCT: Schmidt-Cassegrain. R-C: Ritchey-Chretien. MCT: Maksutov-Cassegrain.

All images were calibrated with dark and flat-field frames and processed with MPO Canopus version 10.4.7.6 (Warner, 2015). Clear and R filter magnitudes were calibrated to the standard system using the method described by Dymock and Miles (2009) and CMC-15 stars with near-solar color indexes selected by using Vizier (2014).

Figure 1. Raw data from 2014 Nov 26. The data cover nine hours, which is more than two complete cycles of the lightcurve. No obvious anomalies are present.

Figure 2. Raw data from 2014 Nov 23. The data more than six hours, which is almost two complete cycles of the lightcurve. An eclipse or occultation is present at the end of the night.

Figure 3. Sixteen nights of data fit to a single period. Note that 3 nights show an obvious lowering of the lightcurve.

Using the single period solution from MPO Canopus we obtained a period of 3.595 ± 0.001 h and an amplitude of 0.19 mag (Figure 3). However it was obvious that the data from at least three nights did not fit well. Using the iterative dual period solution from MPO Canopus we obtained a primary period of 3.5950 ± 0.0001 h with an amplitude of 0.19 mag (Figure 4) and a secondary period (Figure 5) of 21.641 ± 0.002 h. The mutual eclipse/occultation events have amplitudes of 0.08 to 0.15 magnitudes. The first value gives a lower limit on the secondary-to-primary effective diameter ratio of Ds/Dp ≥ 0.28.

The data were sent then to Pravec who confirmed that it was a binary system. Authors DK, LF, and PP announced the discovery through the CBET 4033, published on 2014 Dec 8.

Figure 4: Using the 2-period search within MPO Canopus we obtain the primary period after subtracting out the secondary period.

Figure 5: Using the 2-period search within MPO Canopus we obtain the secondary period after subtracting the primary period.

H and G Determination

For each lightcurve, the R mag was measured using half peak-topeak amplitude with Peranso (Vanmunster, 2014) via a second order polynomial fit and excluding any eclipse/occultation events. The V mag was derived adding the typical color index V-R = 0.49 for an S-type asteroid (Shevchenko and Lupishko, 1998) to the R mag. Using the H-G Calculator function of MPO Canopus, we derived H = 13.63 ± 0.04 mag and G = 0.15 ± 0.05 (Figure 6). This H value is quite different from H = 13.1 published on the JPL Small-Body Database Browser (JPL, 2015).

Figure 6: H and G curve for 3841 Dicicco.

Acknowledgements

The Etscorn Campus Observatory operations are supported by the Research and Economic Development Office of New Mexico Institute of Mining and Technology (NMIMT).

References

ECO (2015), Etscorn Campus Observatory.

http://www.mro.nmt.edu/education-outreach/etscorn-campusobservatory

Bus S.J., Binzel R.P. (2002). “Phase II of the Small Main-Belt Asteroid Spectroscopic Survey – A Feature-Based Taxonomy.” Icarus 158, 146-177.

Dymock, R., Miles, R. (2009). “A method for determining the V magnitude of asteroids from CCD images.” J. Br. Astron. Assoc. 119, 149-156

Harris, A.W., Young, J.W., Bowell, E., Martin, L.J., Millis, R.L., Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne, H., Zeigler, K. (1989). “Photoelectric Observations of Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186.

JPL (2015). http://ssd.jpl.nasa.gov/sbdb.cgi

Shevchenko V.G., Lupishko D.F. (1998). “Optical properties of Asteroids from Photometric Data.” Solar System Research 32, 220-232.

Vanmunster, T. (2014). PERANSO, period analysis software.

http://www.cbabelgium.com and http://www.peranso.com

 

VizieR (2014). http://vizier.u-strasbg.fr/viz-bin/VizieR Warner, B.D. (2015). http://www.minorplanetobserver.com/MPOSoftware/MPOCanopus.htm

ROTATIONAL PERIOD DETERMINATION OF 2717 TELLERVO AND 9773 1993 MG1

Maurizio Scardella, Angelo Tomassini, Francesco Franceschini
ATA (Associazione Tuscolana di Astronomia)
“F. Fuligni” Observatory    (MPC code D06)
Via Lazio, 14 – Rocca di Papa (RM) – 00040 – ITALY nikkor5@gmail.com

The main-belt asteroids (2717) Tellervo and (9773) 1993 MG1 were observed over several nights throughout 2015 May-August in order to determine their synodic rotational period.

The observations of the analysed asteroids were carried out from F. Fuligni Observatory using a 0.35-m f/10 ACF telescope and SBIG ST8-XE CCD camera with Bessel R filter and from Franceschini’s equipment using a 9.25″ f/6.3 reflector telescope equipped with Atik 314L- CCD camera with Astrodon R filter.  All images were dark and flat-field calibrated with Maxim DL. Differential photometry and period analysis was done using MPO Canopus (Warner, 2012).

 

 (2717) Tellervo

The lightcurve of the main-belt asteroid (2717) Tellervo was already carried out from our team during the summer 2012 (see MPB 40-2) but because scattered data acquired, his rotational period resulted quite different with respect to the value calculated in this session. Current version photos were taken during May-June 2015 over five nights. The resulting lightcurve has synodic period P = 4.213 ± 0.001 hours and amplitude 0.40 mag (Fig. 1).

2717_Tellervo_new_process_5_sessions_no27Fig. 1 Curva di luce di 2717 Tellervo

 (9773) 1993 MG1

Discovered in June 1993 by E. F. Helin at Mount Palomar Observatory, this main-belt asteroid were selected from the “Lightcurve Photometry Opportunities: July-Sept 2015” on MPB 42-3 (Warner, 2015). The observations were carried out from “F. Fuligni” Observatory and from Francesco Franceschini during four nights in July 2015.  The derived synodic period was P = 2.67 ± 0.01 h with an amplitude of A = 0.24 mag (Fig. 2).

9773_1993_MG1_3_ord5Fig. 2 Curva di luce di 9773 1993 MG1

 

References

Warner, B.D. (2012). The MPO Software, Canopus version 10.4.1.9. Bdw Publishing, http://minorplanetobserver.com/

Warner, B.D. (2012). The MPO User Guide: A Companion Guide To The MPO Canopus/PhotoRed Reference Manual. BDW Publishing, Colorado Spring, CO.

Warner, B.D. (2013). “Lightcurve of 2717 Tellervo”. Pag. 108. MPC 40-2.

Warner, B.D. (2015) “Lightcurve Photometry Opportunities: July-Sept 2015”. MPC 42-3.

http://www.MinorPlanet.info/PHP/call_OppLCDBQuery.php