The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation
Haumea—one of the four known trans-Neptunian dwarf planets—is a very elongated and rapidly rotating body1, 2, 3. In contrast to other dwarf planets4, 5, 6, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system7, and the Centaur Chiron was later found to possess something similar to Chariklo’s rings8, 9. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea’s equator and the orbit of its satellite Hi’iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea’s spin period—that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea’s largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates1, 10, 11. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.
MASTER OT J190519.41+301524.4:
New Eclipsing Cataclysmic Variable of VY Scl Type
F. Martinelli1, D. V. Denisenko2*
1 Astronomical Center Lajatico, Italy
2 Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
Abstract–MASTER OT J190519.41+301524.4 was discovered as an optical transient of 15.7m by the Mobile Astronomical System of TElescope-Robots in March 2014. We report the results of photometric observations of this variable performed at Lajatico Astronomical Center in June-July 2015. The light curve is showing deep V-shaped eclipses with an amplitude of two magnitudes. The orbital period was determined to be 0.129694 d (3.113 h). Based on the archival observations and the shape of the orbital curve we suggest that MASTER OT J190519.41+301524.4 is a new cataclysmic variable of VY Scl type (“anti-nova”) with an inclination angle close to 90 deg.
Key words: stars, cataclysmic variables, eclipsing binaries
MASTER OT J190519.41+301524.4 is an optical transient in Lyra discovered on Mar. 06, 2014 (Denisenko et al., 2014) by MASTER-Kislovodsk auto-detection system (Lipunov et al., 2010). The previously unremarkable star was found to be highly variable on the digitized Palomar plates. Namely, the star was bright on 1950 June 17 POSS-I plate, but very faint on 1987 June 21 POSS-II plate (see Figure 1). Those changes of brightness are clearly seen from the magnitudes reported in various catalogs. Namely, USNO-B1.0 catalogue (Monet et al., 2003) is listing USNO-B1.0 1202-0321874 with B1=16.32 R1=15.65 B2=17.84 R2=N/A I=16.39, while GSC 2.3.2 is giving Fmag=19.41 measured from 1987 June 21 Palomar plate. The star is an ultraviolet source GALEX J190519.4+301525 with the far and near UV magnitudes FUV=17.66±0.05, NUV=17.46±0.04. Based on this information Denisenko et al. suggested that MASTER OT J190519.41+301524.4 is a cataclysmic variable, most likely the anti-nova of VY Scl type in the high state.
In this article we report the results of our observations of MASTER OT J190519.41+301524.4 obtained in June-July 2015 at Lajatico Astronomical Center in Italy. We have detected the deep eclipses in this compact binary system, measured its orbital period and confirmed the classification as a VY Scl cataclysmic variable.
The observations of J1905+3015 were performed at Lajatico Astronomical Center in Italy http://www.astronomicalcentre.org/ on seven nights (2015 June 28, 30, July 7, 12, 15, 17 and 18) using 0.36-m Cassegrain telescope with SBIG ST-8XME CCD. A total of 203 unfiltered images with 300-sec exposures were obtained (26, 11, 35, 23, 34, 35 and 37 images covering 2.9, 1.4, 3.7, 2.8, 4.1, 3.0 and 3.8 hours, respectively). Nearby star USNO-B1.0 1202-0321923 (0.6′ East and 0.2′ South of the variable) with the magnitude V=12.8 was used as a reference star.
* E-mail: email@example.com
The observing times were converted from JD to Barycentric Julian Date using online period search service http://scan.sai.msu.ru/lk/ by Kirill Sokolovsky. Using Lafler-Kinman and Deeming methods we have obtained the best value of period 0.129694(2) d, or 3.113 hr. The phased light curve from our observations is presented in Figure 2. It is showing deep eclipses with a total amplitude about 2 magnitudes and the variations by 0.3m near the maximum light. Search for the secondary periods has not given any additional periodic signals at higher frequencies.
The deep fading of J1905+3014 observed on the 1987 POSS-II Red plate can be explained either by the low state of a polar (magnetic CV without an accretion disk) or by the drop of accretion rate in the variable of VY Scl type (“anti-nova” with the disk). Our observations are telling strongly in favor of the second scenario. The V-shape and long duration of the eclipse (about 20 per cent of the orbital period) are consistent with the presence of quite a large accretion disk. The system was also not detected by ROSAT all-sky survey (Voges et al., 2003), as one would have expected for a magnetic CV in the 16-18m range.
MASTER OT J190519.41+301524.4 has turned out to be an eclipsing cataclysmic variable of VY Scl type. Systems like that are quite rare. Catalog of cataclysmic binaries by Ritter and Kolb (2003; Version 7.23 of July 2015) lists only eight nova-like variables with eclipses (NL+E), but none of them is classified as “anti-nova”. Interestingly enough, all of them have orbital periods longer than 0.133 d. The phased light curve of J1905+3015 binary system reminds that of V482 Cam = HS 0728+6738 (Rodriguez-Gil et al., 2004) that belongs to the subgroup of eclipsing SW Sextantis star. It is possible that J1905+3015 is also an SW-type star. We encourage the continued monitoring of this new CV to follow its return to the low state. When the system fades back to 18-19m level, it will become a good target to measure the size of the accretion disk and to determine the inclination from the changes in eclipse depth and duration.
Denisenko, D., Balanutsa, P., Lipunov, V., et al., ATel #5953 (2014).
Lipunov, V., Kornilov, V., Gorbovskoy, E., et al., Adv. in Astron., 2010, Art. ID 349171 (2010).
Monet, D. G., Levine, S. E., Canzian, B., et al., Astron. J., 125, 984 (2003).
Ritter, H., Kolb, U., Astron. Astrophys., 404, 301 (2003).
Rodriguez-Gil, P., Gaensicke, B. T., Barwig, H., et al., Astron. Astrophys., 424, 647-655 (2004).
Voges, W., Aschenbach, B., Boller, T., et al., Astron. Astrophys., 349, 389 (1999).
1RXS J161935.7+524630: New Polar with the
Varying Accretion Modes on two Magnetic Poles
D. V. Denisenko1*, F. Martinelli2
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
2 Astronomical Center Lajatico, Italy
Abstract–We report the discovery of a new cataclysmic variable DDE 32 identified with the
ROSAT X-ray source 1RXS J161935.7+524630 in Draco. The variability was originally found by
D. Denisenko on the digitized Palomar plates centered at the position of X-ray source. The
photometric observations by F. Martinelli at Lajatico Astronomical Center in June 2015 have
shown the large amplitude (nearly 2 magnitudes) variability with a period about 100.5 minutes.
Using the publicly available Catalina Sky Survey data from 2005 to 2013 we have improved the
value of period to 0.0697944 days. Comparison of the archival CRTS data with more recent
observations from Lajatico shows the dramatic changes in the light curve shape. Instead of a single
peak present in Catalina data before 2014, there were two peaks of nearly the same height during
2015. SDSS spectrum taken in June 2009 shows prominent Helium emission lines between the
bright Balmer series. He II 4686 Å line has more than 30% effective width compared to Hβ line.
All those features allow us to interpret 1RXS J161935.7+524630 as a magnetic cataclysmic
variable (polar) with the accretion mode changing from one pole before 2014 to two poles in 2015.
Key words: stars, cataclysmic variables
Magnetic cataclysmic variables (polars) are the subclass of CVs with the strong magnetic fields.
They are distinguished from other types of compact white dwarf and red dwarf (WD+RD) binary
systems by the absence of accretion disk and by the presence of one or two hot spots on WD
surface. These properties result in the following observational characteristics: large amplitude of
orbital variability (up to 2 magnitudes); sharp drops of brightness caused by the disappearance of
the hot spot behind the limb; irregular light curves on the long time scales; high X-ray to optical
ratio; presence of ionized Helium lines in their spectra. Those features allow to distinguish the
polars from other nova-like variables and dwarf novae with accretion disks who have smoother
orbital light curves and smaller amplitudes of variability on the time scales of hours. Magnetic
CVs are further divided into three subtypes: AM Her (“classical” polars), BY Cam (asynchronous
polars) and DQ Her (intermediate polars, or IPs), see Andronov, 2007. AM type polars have the
WD rotation synchronized with the orbital period, while IPs have white dwarfs rotating faster than
the orbital period, with Pspin typically less than 0.1 Porb. Orbital periods of polars cover nearly the
same wide range as dwarf novae, from 1.3 to 4 hours (0.054–0.16 days) and rarely a bit longer.
Many polars are showing significant long-term changes of the average brightness. Some AM Her
systems have prolonged high states with the “excursions” to low states lasting for several months
and even years. Several systems show “chameleon” changes of the light curve caused by the
accretion stream switching from one magnetic pole to the other. And in addition to that, several
systems can change the accretion mode from one pole to two poles at the same time.
* E-mail: firstname.lastname@example.org
In this article we report the discovery and the following analysis of a new cataclysmic variable
DDE 32 in Draco identified with the ROSAT X-ray source 1RXS J161935.7+524630. The first
chapter describes how the variable was discovered. In the next part we analyze the spectrum of
this variable obtained by Sloan Digital Sky Survey. The third chapter is devoted to the photometric
observations, determination of orbital period and study of long term variations of the phased light
curve. Then we discuss the possible interpretation of the observed properties of this variable. Our
conclusion is that 1RXS J161935.7+524630 is a new magnetic cataclysmic variable (polar of AM
Her type) with the accretion mode changing from one pole to two poles.
The variability of DDE 32 was found by one of the authors (D.D.) back in December 2007 in the
process of identifying X-ray sources from the ROSAT bright source catalogue 1RXS (Voges et
al., 1999). The object 1RXS J161935.7+524630 (J1619+5246 for the brevity) is one of the bright
ROSAT sources with the flux of (0.135±0.017) cnts/s in 0.2–10 keV band and hardness ratios
HR1=–0.45±0.09, HR2=0.42±0.18. Statistical error of 1RXS position is 8″. The star USNO-B1.0
1427-0327171 with the coordinates R.A. = 16 19 35.75, Dec. = +52 46 32.0, proper motions
pmRA=14 mas/yr, pmDE=–6 mas/yr and magnitudes B1=20.16 R1=19.17 B2=19.06 R2=18.25
I=17.25 was found to be highly variable on the digitized Palomar plates. Figure 1 is showing the
variable on three Palomar Red plates: 1954 June 28 (POSS-I), 1991 July 03 and 1993 April 25
(POSS-II). The large amplitude of variability is obvious. The magnitude range was determined to
be 16.8–20:. The nature of the object was not clear at the time of discovery. The 2MASS
photometry was misleading with the (J-K) color index of 2MASS J16193575+5246326
(J=16.71±0.16 H=16.16±0.19 K=15.52±0.23) being consistent with that of quasars, despite the
non-zero proper motion in USNO-B1.0. The object was considered to be too red for a cataclysmic
variable (J-K=1.2±0.3) and neglected for nearly four years.
In September 2011 D.D. came across the spectrum of J1619+5246 obtained with the Sloan Digital
Sky Survey on MJD=54983 (2009 June 01). It is shown at Figure 2. Despite the automatic
classification as a star of B6 spectral type by SDSS processing routines, the spectrum is clearly
that of a cataclysmic variable. It shows Balmer emission lines from Hα to Hη and in addition
several Helium lines, including He II 4686 Å one characteristic for polars. The object has regained
the attention again and was added to the list of variable stars discovered by the first author as DDE
32. See http://scan.sai.msu.ru/~denis/VarDDE.html for the color-combined finder chart of
J1619+5246 and additional information.
After the confirmation of CV nature of J1619+5246 from SDSS spectrum the new variable star
was added to the monitoring program with the Bradford Robotic Telescope (BRT; since 2016
Autonomous Robotic Telescope, or ART) at http://www.telescope.org/. The object was in the low
state on most BRT images obtained in 2011-2014, being not visible on 60-sec unfiltered exposures
with the 0.35-m Schmidt–Cassegrain telescope and Galaxy camera based on FLI MicroLine CCD
(typical limit about 19m). SDSS magnitudes (u=18.87 g=18.99 r=18.85 i=18.50 z=18.28) are also
on the fainter side of J1619+5246 variability range.
However, in April 2015 the object has appeared brighter than 18m on two BRT images in a row,
and D.D. has asked F.M. to start an observing run at Lajatico Astronomical Center in Italy
http://www.astronomicalcentre.org/. The observations were performed on four clear nights (2015
June 17, 24, 26 and 27) using 0.36-m Cassegrain telescope with SBIG ST-8XME CCD. A total of
101 unfiltered images with 300-sec exposures were obtained (24, 19, 40 and 18 images covering
2.6, 2.0, 3.3 and 1.7 hours, respectively).
Using the combined data set resulting in 9.6 hours of effective time we have searched for the
orbital period. The observing times were converted from JD to Barycentric Julian Date using
online period search service http://scan.sai.msu.ru/lk/ by Kirill Sokolovsky. Using Lafler-Kinman
and Deeming methods we have obtained the best value of period 0.06980(2) d, or 1.6752 hr. The
nearby USNO-B1.0 1427-0327222 = SDSS J161945.69+524749.8 was used a reference star with
R=16.15 and USNO-B1.0 1427-0327149 as a check star.
Then we have downloaded publicly available Catalina Sky Survey data (Drake et al., 2009) for
this object from CRTS DR2 website http://nesssi.cacr.caltech.edu/DataRelease/ and combined
them with our observations. CRTS has a total of 169 points for CSS_J161935.8+524631 from
2005 May 15 to 2013 October 24. Time of observations was converted from MJD to JD adding
2400000.5 to Catalina values and then corrected for barycenter, as described above. Applying
Lafler-Kinman method to the combined dataset we have obtained the more precise value of period
equal to 0.0697944(2) d.
The light curve of J1619+5246 from CRTS data during 2005 to 2013 folded with the best period
is shown at Figure 3, and the light curve from our observations in 2015 is given at Figure 4. The
change in the shape of the light curve is obvious. Before 2014 there was one prominent peak on
the period near the zero phase, while the 2015 light curve is characterized by two peaks nearly
equal in height. Also, the average level of brightness has increased in 2015 compared to 2005-
X-ray source 1RXS J161935.7+524630 is characterized by hardness ratios HR1=–0.45±0.09,
HR2=0.42±0.18 in ROSAT catalog. The negative value of HR1 differs remarkably from the
typical numbers for other subtypes of cataclysmic variables, namely for dwarf novae (HR1 from
0.9 to 1.0). The values like that are actually more typical for quasars rather than for CVs. Combined
with 2MASS (J-K) color index of 1.2 that has prevented this CV from discovery back in 2007.
However, the value of (J-K) for the objects at J=16.7 and K=15.5 should be taken with caution
since these infrared magnitudes are close to the limit of 2MASS survey.
Variable name 1RXS name X-ray count rate Hardness 1 Hardness 2
BY Cam J054249.9+605132 1.499±0.066 –0.10±0.04 0.47±0.05
V1432 Aql J194011.6–102529 0.318±0.033 0.72±0.08 0.23±0.11
CD Ind J211540.9-584045 0.380±0.044 –0.02±0.10 0.39±0.14
RX J0524+42 J052430.2+424449 0.075±0.014 0.61±0.19 0.46±0.19
DDE 32 J161935.7+524630 0.135±0.017 –0.45±0.09 0.42±0.18
Table 1. Comparison of X-ray parameters of selected known polars with asynchronously rotating
white dwarfs and DDE 32.
The star is also an UV source GALEX J161935.8+524631 with the far and near UV magnitudes
FUV=18.75±0.10, NUV=18.96±0.06. They are matching well with SDSS magnitudes (u=18.87
g=18.99 r=18.85 i=18.50 z=18.28). The optical (g-r), (r-i) indices correspond well to the colorperiod
CV relation for an object with P=0.0698 d. Though the relationship by Kato et al. (2012) is
based mostly on SDSS colors of dwarf novae, it can be used for estimating the orbital periods and
spectral types of secondary components for the polar CVs. The contribution of the secondary
component in this binary system is too small to cause the large (J-K) infrared excess in 2MASS
Pole switching has been observed in several magnetic cataclysmic binary systems before. The
most known example is BY Cam (Mason et al., 1998; Pavlenko et al., 2007). This system is
characterized by the WD rotation period close to the orbital one (Pspin=0.990*Porb) which is causing
beat phenomenon. Further study is required to measure the rotation period of WD in DDE 32 =
J1619+5246 and to verify its classification as AM Her (“normal” polar) or BY Cam (asynchronous
We conclude that DDE 32 = 1RXS J161935.7+524630 is a new magnetic cataclysmic variable
(polar) with the orbital period P=0.0697944(2) days and changing geometry of accretion. The
interval of 2005-2013 covered by Catalina Sky Survey was characterized by the accretion to one
magnetic pole of the white dwarf, as seen from the single peak on the light curve (Figure 3). On
the other hand, during our observations in June 2015 the object was in two-pole accretion mode,
as shown by two peaks of nearly equal height (Figure 4). Since the phase of the first peak in 2015
data matches that of main peak in 2005-2013, we conclude that this peak is caused by the persistent
hot spot near one of magnetic poles on WD surface. The second peak near the phase 0.5 is the
second hot spot on the other magnetic pole that has “turned on” at some moment in Spring 2015,
as seen from the increasing level of brightness in 2014-2015 BRT data. There is a possibility of
DDE 32 being an asynchronous rotator similar to BY Cam. The continued monitoring of this
exciting cataclysmic binary system is highly encouraged. The time-resolved spectroscopy and
spectral lines tomography is very much desired for this non-stationary object in Draco.
Andronov, I. L., ASP Conference Series 362, 200 (2007).
Drake, A. J., Djorgovski, S. G., Mahabal, A., et al., Astrophys. J. 696, 870 (2009).
Kato, T., Maehara, H., Uemura, M. PASJ 64, 63 (2012).
Mason, P. A., Ramsay, G., Andronov, I., MNRAS 295, 511 (1998).
Pavlenko, E., Babina, J., Andreev, M. ASP Conference Series 372, 537 (2007).
Voges, W., Aschenbach, B., Boller, T., et al., Astron. Astrophys. 349, 389 (1999).
Figure 1. DDE 32 = 1RXS J161935.7+524630 on the digitized Palomar Red plates. Left to right:
1954 June 28 (faint state), 1991 July 03 (medium brightness) and 1993 April 25 (bright state).
FOV is 5’x5′, North is up and East is at left.
Figure 3. Light curve of J1619+5246 from Lajatico data (June 2015) folded with the same orbital
period and the same initial epoch T0=2454923.966 (HJD).
Lajatico Astronomical observatory pubblications.
Optical and X-ray behaviour of the high mass X-ray transient A0535+26/HDE245770 in February-March 2014
The optical behaviour of the Be star in the high-mass X-ray transient A0535+26/HDE245770 shows that at periastron the luminosity is typically enhanced by 0.02 to a few tenths magnitude, and the X-ray outburst occurs eight days after the periastron. Indeed, at the periastron an increase of the mass flux occurs. This sort of flush reaches the external part of the temporary accretion disk around the neutron star and moves to the hot central parts of the accretion disk and the neutron star surface. The time necessary for this way is dependent on the turbulent viscosity in the accretion disk, as discussed by Giovannelli, Bisnovatyi-Kogan, and Klepnev (2013) (GBK13). In this paper we will show the behaviour of this system in optical band around the predicted periastron passage on 21st February 2014, by using the GBK13 ephemeris that we used to schedule our spectroscopic and photometric optical observations. Spectroscopic unusual activity detected in the Balmer lines and the enhancement in the emission in B, V, and R bands around the periastron passage, and the subsequent X-ray event definitively demonstrate the existence of about 8 day delay between optical and X-ray flares.
Link to web site: http://arxiv.org/abs/1409.3434
Transito Esopianeta XO-1 in collaboration with ETD. By Fabio Martinelli, Marco Monaci e Giorgio Corfini http://var2.astro.cz/EN/tresca/transit-detail.php?id=1407428699
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. IV: The Fourth Year (2011-2012)
http://arxiv.org/abs/1210.0678 Astronomicalcentre staff in collaborazione con: Mariinsjaya High School, Odessa Ukraine Odessa National Martime University, Odessa Ukraine Scopritori: M.Mogoryan, Natalia Virnina & Fabio Martinelli Scoperta di 7 nuove stelle variabili tra la costellazione di Pegaso e Lacerta. Uno studio di circa un anno, un monitoraggio effettuato con il telescopio da 25cm SC dell’osservatorio astronomico Montecatini Val di Cecina Pisa, e l’osservatorio astronomico I telescope.net. 1° stella variabile, tipo EA, coordinate: 22 46 57.72, +34 05 55.2 Image:
1. Secondary minimum: HJD = 2456536.8522.O’Connell effect (O’Connell 1951) is possible. Alternative period is 0d.5549. MinII = 13m.649.
2° stella variabile, tipo EW, coordinate: 22 47 08.02, +34 14 21.6
2. Secondary minimum: HJD = 2456534.8598. MinII = 17m.10
3° stella variabile, tipo EW, coordinate: 22 47 17.68, +34 06 37.2
3. Secondary minimum: HJD = 2456535.8633. MinII = 15m.18.
4° stella variabile, tipo EW, coordinate: 22 48 27.69, +34 13 50.9
5° stella variabile, tipo EA, coordinate: 22 48 34.85, +34 15 22.0
5. Secondary minima: HJD = 2456159.6101, HJD = 2456224.3904, HJD = 2456559.5520. The phase curve is combined of unfiltered observations, collected in 2012 with Mead 10″ (black points); R-filtered observations obtained in 2013 with the same telescope (blue points); and R-filtered observations, made with the T5 telescope of the iTelescope.net observatory (red points).
6° stella variable, tipo, EB, coordinate: 22 49 47.54, +34 00 55.8
6. Primary minima: HJD = 2456535.9370, HJD = 2456542.7177. MinII = 14m.32. O’Connell effect is clearly present. A total eclipse in the primary minimum is possible. The orbital inclination is close to 90°. Another interesting feature is a rather large difference in minima depths: minI – minII = 0m.28. Despite the shape of the light curve and the period, which are typical of EW-type binaries, the components of this binary do not show thermal contact.
7° stella variabile, tipo, EW, coordinate: 22 50 10.69, +34 04 56.3
7. MinII = 14m.97. Articolo completo sul sito:
W. E. Green
(MSU) Russia Autori Denis Denisenko e Fabio Martinelli http://arxiv.org/abs/1207.6320 Osservazione del transito HAT-P-5 con telescopio da 25 cm focale 1600 camera ccd DTA con sensore KAF1600, no Observation of transit HAT-P-5 with telescope 25 cm focal 1600 mm ccd, camera DTA with KAF 1600 09/07/12
Pubblication of the transit HD 189733 b in collaboration with Czech Astronomical Society . Authors Fabio Martinelli and Giorgio Corfini.
Pubblication of the transit KOI0135 b in collaboration with Czech Astronomical Society . Authors Fabio Martinelli and Giorgio Corfini.
Pubblication of the transit HD 189733 b in collaboration with Czech Astronomical Society . Authors Fabio Martinelli and Giorgio Corfini.
Pubblication of the transit KOI 0196 b in collaboration with Czech Astronomical Society . Authors Fabio Martinelli and Giorgio Corfini.
Pubblication of the transit TRES-3 in collaboration with Czech Astronomical Society . Authors Fabio Martinelli and Giorgio Corfini.
Pubblication of obsevation of SN in NGC 5775 in collaboration with ISSP, Italian Supernovae Search Project, Observation by Fabio Martinelli and Fabio Briganti.
Pubblication of the transit Wasp-14 in collaboration with Czech Astronomical Society & Luigi Mancini Max Plank Instutute for astronomy Germany. Authors Fabio Martinelli and Giorgio Corfini.
Telescope Cassegrain 356 mm focal lenth 2500 CCD SBIG ST8XME KAF1600.
Pubblication of the transit GJ1214 in collaboration with Czech Astronomical Society & Luigi Mancini Max Plank Instutute for astronomy Germany. Authors Fabio Martinelli and Giorgio Corfini.
Telescope Cassegrain 302 mm focal lenth 2000 CCD SBIG KAF1600.
Exoplanet transit of WASP-43 By Fabio Martinelli and data reduction by Giorgio Corfini Telescope 356 mm focal lenth 2257 mm, CCD camera ST-8XME Baader yellow filter 495nm.
Latest supernovae, discovered SN in NGC 5806
Discovered a SN by Fabio Briganti and Alessandro Dimai in NGC 5806. The transient, discovered by Fabio Briganti (Santa Croce sull’Arno – PI) in poor seeing condition, with the SC 11″ f/6,3 of the Col Drusciè Observatory, in the cours of Italian Supernovae Search Project, needs a confirmation, because there is only a frame of the suspect. No known minor planets in the field at the time of discovery. Nothing is visible in red and blue plates of Palomar Sky Survey POSS2.
you can find the discovery image.
Congratulation to Fabio Briganti and Alessandro Dimai Up date about the SN in NGC 5806 cause it’s very interesting and bright supernova.
The PTF (ATEL #1964, #3253; http://www.astro.caltech.edu/ptf ) reports the discovery of a new supernova in NGC 5806 (independently discovered by F. Briganti and reported as PSN J14595904+0153251 on Jan 22). The source is located at RA = 14:59:59.08, Dec = +01:53:24.2 (J2000), was first detected by the Palomar 1.2m telescope with an R-band magnitude of about 17 on 2012 Jan 10 (UT) and brightened to about 16.1 mag on Jan 20. PTF did not detect the source prior to 2012 Jan 5. Spectroscopic follow-up was performed with the HET (+LRS) on Jan 14, the INT (+IDS) on Jan 15-18, Gemini N (+GMOS) on Jan 17 and the Palomar 5m (+DBSP) on Jan 18. The spectra show prominent H features as well as He absorption at about 10,000 km/s, consistent with a type IIb classification. Credential Certification: Christopher J. Stockdale (email@example.com)
Subjects: Radio, X-ray, Supernovae
We report the detection of radio emission near the position of the type-IIb supernova PTF2012os (ATEL #3881) with the Karl G. Jansky Very Large Array radio telescope in the DnC configuration: A flux density of 0.44 +/- 0.05 mJy was measured at 5.02 GHz (wavelength 6.0 cm) on 2012 Jan. 22.42 UT. The measured position of the radio emission of R.A. = 14h59m59.s12, Decl. = +01d53m23s.3, equinox 2000.0 is in good agreement with the measured optical position of (ending digits) R.A. = 59.s08, Decl. = 24s.2, equinox 2000.0 (ATEL #3881). Radio observations are continuing. Using 9.4 ks of co-added Swift X-Ray Telescope (XRT) data, obtained on 2012-01-14 (2.0 ks exposure time; PI Kasliwal), 2012-01-16 (2.4 ks; PI Kasliwal), and 2012-01-24 (5.0 ks; PI Immler), no X-ray source is detected at the position of the SN. The PSF, dead-time, and vignetting corrected upper limit to the XRT net count rate is 1.1E-03 cts/s (3-sigma), corresponding to an unabsorbed (0.2-10 keV band) X-ray flux limit of 5.4E-14 erg/cm/cm/s and a luminosity limit of 4.2E39 erg/s for an adopted thermal plasma spectrum with a temperature of kT = 10 keV, a Galactic foreground column density of 4.14E+20 (Dickey & Lockman, 1990, ARAA 28) and a distance of 25.4 Mpc (NED). Swift observations are continuing. The object warrants further study in all wavelength bands. Credential Certification: Schuyler D. Van Dyk (firstname.lastname@example.org)
Schuyler D. Van Dyk (Spitzer Science Center/Caltech), Avishay Gal-Yam, Iair Arcavi (Weizmann Institute), Mansi M. Kasliwal (OCIW/Princeton), and Assaf Horesh (Caltech), on behalf of the larger PTF collaboration, report their attempt to identify the progenitor of the Type IIb supernova PTF12os, aka PSN J14595904+0153251, in archival Hubble Space Telescope (HST) ACS/WFC F435W, F555W, and F814W images from 2005 March 10 UT (PI: Smartt). We have astrometrically matched a B-band image (with 0.87″ seeing) from 2012 January 18 UT obtained with the IMACS camera on the Magellan Baade 6.5 m telescope at Las Campanas Observatory, Chile, with the ACS F435W image, using 10 fiducial stars in common. The SN position has been located on the ACS image with an uncertainty of 0.57 WFC pixel, or 0.028″. This is within 1 WFC pixel, to the southwest, of a candidate source detected in all three ACS bands. The site of PTF12os lies approximately 2.2″ southeast of the position of the Type II SN 2004dg in this same host galaxy. Preliminary photometry of the ACS images using Dolphot (Dolphin 2000, PASP, 112, 1383) results in a brightness for the object of B=23.30, V=23.04, and I=22.53 (uncertainties are all 0.012 mag or smaller). Assuming the average value of the distance modulus to the host, NGC 5608, from the NASA/IPAC Extragalactic Database (NED), 32.01 mag, and also assuming only the Galactic foreground extinction at V-band from Schlegel, Finkbeiner, & Davis (1998, ApJ, 500, 525), 0.17 mag, this object had V absolute magnitude of -9.1 and absolute colors (B-V)_0=0.21 and (V-I)_0=0.44 (consistent with an early F spectral type). This could be a highly-luminous supergiant star, or, alternatively, a compact star cluster. Evidence exists from the strength of the Na I D lines in follow-up spectra (ATel 3881) that the extinction to the SN could, in fact, be higher, implying that the source is even more luminous and bluer. We tentatively identify this source as a candidate for the progenitor, although given the offset of the SN position from the object’s centroid, the host galaxy distance, and the inferred higher extinction, it is quite possible that the progenitor has not been detected. Higher-resolution imaging is pending for candidate confirmation, and further analysis is ongoing. Credential Certification: Assaf Horesh (email@example.com)
Subjects: Millimeter, Supernovae
We report a CARMA observation of the type IIb supernova PTF12os (Arcavi et al.; ATEL# 3881). The observation was undertaken on 2012 Jan 14.65 UT. We report a null-detection in the 3-mm band (at a center frequency of 93 GHz) with a 3 sigma upper limit of 0.36 mJy/beam. We thank the CARMA staff for scheduling this target of opportunity. Pubblicazione della scoperta.
Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: firstname.lastname@example.org (alternate email@example.com) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2012P IN NGC 5806 = PSN J14595904+0153251 Alessandro Dimai, Cortina d'Ampezzo, Italy, on behalf of the Italian Supernovae Search Project (ISSP), reports the discovery by Fabio Briganti (Santa Croce sull'Arno, Pisa, Italy) of an apparent supernova (mag about 15.0) on unfiltered CCD images (limiting mag about 16.5) taken with the "Maioni" 0.28-m telescope of the Osservatorio Astronomico del Col Druscie at Cortina d'Ampezzo, Italy, on Jan. 22.1556 UT. The new object is located at R.A. = 14h59m59s.12, Decl. = +1d53'24".4 (equinox 2000.0), which is 10" west and 1" south of the nucleus of NGC 5806. Nothing is visible at this position on Palomar Sky Survey infrared, red, and blue plates. The discovery image is posted at website URL http://tinyurl.com/7lzoeyv. The variable was designated PSN J14595904+0153251 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012P based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2012P (unfiltered unless noted otherwise): 2011 Dec. 7, [18.0 (ISSP); 2012 Jan. 23.227, 15.2 (Briganti); 23.549, 16.3 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K camera + luminance filter at the New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 59s.09, 24".1; image posted at URL http://www.flickr.com/photos/43846774@N02/6752536997/). The type-II supernova 2004dg also appeared in NGC 5806 (cf. IAUC 8375). L. Borsato and V. Nascimbeni, Dipartimento di Fisica e Astronomia, Universita di Padova; and S. Benetti, A. Pastorello, S. Valenti, L. Tomasella, E. Cappellaro, P. Ochner, and M. Turatto, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, report that a spectrum (range 360-810 nm; resolution 2.2 nm) of PSN J14595904+0153251 = SN 2012P was obtained on Jan. 23.17 UT with the Ekar-Copernico 1.82-m telescope (+ AFOSC). Using a library of supernova spectra via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383; available via https://gelato.tng.iac.es/login.cgi), they found a best match with typical type-Ib/c supernovae soon after maximum if a redshift of z = 0.004533 (Falco et al. 1999, PASP 111, 438; via NED) is assumed. From the minimum of a deep-intense absorption measured at 627.6 nm, an expansion velocity of about 5100 km/s is deduced for the ejecta if identified with Si II 635.5-nm (but an expansion velocity of about 14400 km/s if identified with H-alpha). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 January 25 (CBET 2993) Daniel W. E. Green