scholarly journals 523676 (2013 UL10): the first active red centaur

2018 ◽  
Vol 620 ◽  
pp. A93 ◽  
Author(s):  
E. Mazzotta Epifani ◽  
E. Dotto ◽  
S. Ieva ◽  
D. Perna ◽  
P. Palumbo ◽  
...  
Keyword(s):  
Production Rate ◽  
Canary Islands ◽  
Colour Index ◽  
Nucleus Size ◽  
Dust Production ◽  
La Palma ◽  
Upper Limit ◽  
Nucleus Surface ◽  
Perihelion Passage

Aims. We present observations of 523676 (2013 UL10), a centaur orbiting between Jupiter and Uranus that is dynamically similar to the few tens of active centaurs that are currently known. Methods. We analysed visible BVR images of the centaur obtained at the Telescopio Nazionale Galileo (La Palma, Canary Islands, Spain) to investigate the weak comet-like activity and to derive information on the nucleus surface colours and size. Results. Centaur 523676 (2013 UL10) is the only centaur known so far that has both comet-like activity and red surface colours: its nucleus has a colour index [B – R] = 1.88 ± 0.11. The nucleus R magnitude (R = 20.93 ± 0.09) allowed us to derive an upper limit for its nucleus size of D ≤ 10 km. We estimated its dust production rate to be Qd ~ 10 kg s−1 at 6.2 au (just after its perihelion passage), resulting in a timescale for the surface blanketing process τB of approximately tens of years, which is very short with respect to typical dynamical lifetime inside the group. Future monitoring of 523676 (2013 UL10) is needed to further constrain the blanketing model for active centaurs and its timescale.

scholarly journals Spectra of comet C/2002 T7 (LINEAR)

2020 ◽  
Vol 10 (2) ◽  
pp. 43-47
Author(s):  
O. S. Shubina ◽  
N. V. Borisov ◽  
V. K. Rosenbush ◽  
O. V. Ivanova
Keyword(s):  
Production Rate ◽  
Wavelength Range ◽  
Special Astrophysical Observatory ◽  
Dust Production ◽  
Perihelion Passage

We present the results of spectral observations of comet C/2002 T7 (LINEAR) carried out at the 1-m Zeiss-1000 telescope of the Special Astrophysical Observatory (Russia). The spectra were obtained within the 3500-7500 Å wavelength range on November 13, 14, and 21, 2003, before the perihelion passage, when heliocentric and geocentric distances of the comet were about 2.7 AU and 1.8 AU, respectively. Spectra do not show any emission features from the strongest cometary emissions of the CN, C2, and C3 molecules. The normalised spectral gradient of reflectivity is 2.8% per 1000 Å and 5.4% per 1000 Å for November 14 and 21, respectively. The Afρ parameter, which characterises the dust production rate in the comet, is on average about 800 cm. Comet C/2002 T7 (LINEAR) can be classified as belonging to the group of dusty comets

scholarly journals Photometry of distant active comet C/2010 S1 (LINEAR)

2014 ◽  
Vol 4 (1-2) ◽  
pp. 38-41 ◽  
Author(s):  
O. Shubina ◽  
I. Kulyk ◽  
P. Korsun ◽  
Ya. Romanjuk
Keyword(s):  
Physical Activity ◽  
Solar Radiation ◽  
Production Rate ◽  
Spectral Region ◽  
Heliocentric Distance ◽  
Brightness Distribution ◽  
Colour Index ◽  
Dust Particles ◽  
Dust Production ◽  
Photometric Observations

We present the results of photometric observations of a dynamically new comet C/2010 S1 (LINEAR), conducted on June 18, 2012. The comet demonstrated a considerable level of physical activity at a heliocentric distance of 6.3 AU. The brightness, measured under a phase angle of 8.9 degrees, was equal to 14.55m ± 0.06m and 14.21m ± 0.04 m in V- and R-bands, respectively. The brightness distribution over the coma was found to be inversely proportional to the projected onto the sky plane nucleocentric distance, with a slope of approximately −1. Therefore, the calculated Afρ parameter, approximately 8400 cm and 8200 cm for V and R filters, respectively, was used to estimate the dust production rate. Assuming a steady outflow of dust particles from the nucleus, the dust production rate was estimated to be between 20 and 60 kg/s, depending on the assumed value of the grain's albedo. The V-R colour index obtained from the near-nucleus region of the coma is in agreement with the solar V-R colour index, and does not indicate significant reddening of the reflected solar radiation in the spectral region of 540-683 nm.

scholarly journals Activity of the first interstellar comet 2I/Borisov around perihelion: results from Indian observatories

2021 ◽  
Vol 502 (3) ◽  
pp. 3491-3499
Author(s):  
K Aravind ◽  
Shashikiran Ganesh ◽  
Kumar Venkataramani ◽  
Devendra Sahu ◽  
Dorje Angchuk ◽  
...  
Keyword(s):  
Solar System ◽  
Production Rate ◽  
Rate Ratio ◽  
Carbon Chain ◽  
Astronomical Observatory ◽  
Nucleus Size ◽  
Chain Molecules ◽  
Molecular Emission ◽  
Imaging And Spectroscopy ◽  
Gas Ratio

ABSTRACT Comet 2I/Borisov is the first true interstellar comet discovered. Here, we present results from observational programs at two Indian observatories, 2 m Himalayan Chandra Telescope at the Indian Astronomical Observatory, Hanle (HCT) and 1.2 m telescope at the Mount Abu Infrared Observatory (MIRO). Two epochs of imaging and spectroscopy were carried out at the HCT and three epochs of imaging at MIRO. We found CN to be the dominant molecular emission on both epochs, 2019 November 30 and December 22, at distances of rH = 2.013 and 2.031 au, respectively. The comet was inferred to be relatively depleted in Carbon bearing molecules on the basis of low C2 and C3 abundances. We find the production rate ratio, Q(C2)/Q(CN) = 0.54 ± 0.18, pre-perihelion and Q(C2)/Q(CN) = 0.34 ± 0.12 post-perihelion. This classifies the comet as being moderately depleted in carbon chain molecules. Using the results from spectroscopic observations, we believe the comet to have a chemically heterogeneous surface having variation in abundance of carbon chain molecules. From imaging observations, we infer a dust-to-gas ratio similar to carbon chain depleted comets of the Solar system. We also compute the nucleus size to be in the range 0.18 km ≤ r ≤ 3.1 km. Our observations show that 2I/Borisov’s behaviour is analogous to that of the Solar system comets.

scholarly journals Paleomagnetism and40Ar/39Ar ages from La Palma in the Canary Islands

2000 ◽  
Vol 1 (9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Lisa Tauxe ◽  
Hubert Staudigel ◽  
Jan R. Wijbrans
Keyword(s):  
Canary Islands ◽  
La Palma

Grazing effects on species composition in different vegetation types (La Palma, Canary Islands)

2011 ◽  
Vol 37 (3) ◽  
pp. 230-238 ◽  
Author(s):  
J.R. Arévalo ◽  
L. de Nascimento ◽  
S. Fernández-Lugo ◽  
J. Mata ◽  
L. Bermejo
Keyword(s):  
Species Composition ◽  
Canary Islands ◽  
Vegetation Types ◽  
La Palma ◽  
Grazing Effects

Diffuse H2 degassing studies: a useful geochemical tool for monitoring Cumbre Vieja volcano, La Palma, Canary Islands

2021 ◽  
Author(s):  
Nemesio M. Pérez ◽  
Gladys V. Melián ◽  
Pedro A. Hernández ◽  
María Asensio-Ramos ◽  
Eleazar Padrón ◽  
...  
Keyword(s):  
Canary Islands ◽  
Emission Rate ◽  
Monitoring Program ◽  
Hydrothermal Systems ◽  
Sequential Gaussian Simulation ◽  
Homogeneous Distribution ◽  
La Palma ◽  
Soil Degassing ◽  
Geothermal Activity ◽  
Cumbre Vieja

<p>Hydrogen (H<sub>2</sub>) is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas. Although H<sub>2</sub> can be produced in soils by N<sub>2</sub>-fixing and fertilizing bacteria, soils are considered nowadays as sinks of molecular hydrogen (Smith-Downey et al. 2006). Because of its chemical and physical characteristics, H<sub>2</sub> generated within the crust moves rapidly and escapes to the atmosphere. These characteristics make H<sub>2</sub> one of the best geochemical indicators of magmatic and geothermal activity at depth. Cumbre Vieja volcano (La Palma, Canary Islands) is the most active basaltic volcano in the Canaries with seven historical eruptions being Teneguía eruption (1971) the most recent one. Cumbre Vieja volcano is characterized by a main north–south rift zone 20 km long, up to 1950 m in elevation and covering an area of 220 km<sup>2</sup> with vents located at the northwest and northeast. Cumbre Vieja does not show any visible degassing (fumaroles, etc.). For that reason, the geochemical volcano monitoring program at Cumbre Vieja volcano has been focused on soil degassing surveys.  Here we show the results of soil H<sub>2</sub> emission surveys that have been carried out regularly since 2001. Soil gas samples were collected in about 600 sampling sites selected to obtain a homogeneous distribution at about 40 cm depth using a metallic probe and 60 cc hypodermic syringes and stored in 10 cc glass vials. H<sub>2</sub> content was analysed later by a VARIAN CP4900 micro-GC. A simple diffusive emission mechanism was applied to compute the emission rate of H<sub>2</sub> at each survey. Diffuse H<sub>2</sub> emission values were used to construct spatial distribution maps by using sequential Gaussian simulation (sGs) algorithm, allowing the estimation of the emission rate from the volcano. Between 2001-2003, the average diffuse H<sub>2</sub> emission rate was ∼2.5 kg·d<sup>−1</sup> and an increase of this value was observed between 2013-2017 (∼16.6 kg·d<sup>−1</sup>), reaching a value of 36 kg·d<sup>−1</sup> on June 2017, 4 month before the first recent seismic swarm in October, 2017 at Cumbre Vieja volcano. Six additional seismic swarms had occurred at Cumbre Vieja volcano (February 2018, July-August 2020; October 8-10, 2020; October 17-19, 2020, November 21, 2020 and December 23-26, 2020) and changes of diffuse H<sub>2</sub> emission related to this unrest had been observed reaching values up to ∼70 kg·d<sup>−1</sup>. Diffuse H<sub>2</sub> emission surveys have demonstrated to be sensitive and excellent precursors of magmatic processes occurring at depth in Cumbre Vieja. Periodic diffuse H<sub>2</sub> emission surveys provide valuable information to improve and optimize the detection of early warning signals of volcanic unrest at Cumbre Vieja volcano.</p>

scholarly journals Geochemical and Volcanological Evolution of La Palma, Canary Islands

2017 ◽  
Vol 58 (6) ◽  
pp. 1227-1248 ◽  
Author(s):  
Andreas Klügel ◽  
Karsten Galipp ◽  
Kaj Hoernle ◽  
Folkmar Hauff ◽  
Simon Groom
Keyword(s):  
Canary Islands ◽  
La Palma

scholarly journals Narrow-band photometry of Long Period Comets with TRAPPIST telescopes in 2019-2020

2020 ◽  
Author(s):  
Youssef Moulane ◽  
Emmanuel Jehin ◽  
Francisco José Pozuelos ◽  
Jean Manfroid ◽  
Zouhair Benkhaldoun ◽  
...  
Keyword(s):  
Solar System ◽  
Production Rate ◽  
Heliocentric Distance ◽  
Narrow Band ◽  
Maximum Activity ◽  
The Sun ◽  
Water Production ◽  
Dust Production ◽  
Long Period ◽  
Water Production Rate

<p>Long Period Comets (LPCs) have orbital periods longer than 200 years, perturbed from their resting place in the Oort cloud. Such gravitational influences may send these icy bodies on a path towards the center of the Solar system in highly elliptical orbits. In this work, we present the activity and composition evolution of several LPCs observed with both TRAPPIST telescopes (TS and TN) during the period of 2019-2020. These comets include: C/2017 T2 (PANSTARRS), C/2018 Y1 (Iwamoto), C/2018 W2 (Africano), and disintegrated comet C/2019 Y4 (ATLAS). We monitored the OH, NH, CN, C<sub>2</sub> and C<sub>3</sub> production rates evolution and their chemical mixing ratios with respect to their distances to the Sun as well as the dust production rate proxy (A(0)fp) during the journey of these comets into the inner Solar system.</p> <p><strong>C/2017 T2 (PANSTARRS)</strong> is a very bright comet which was discovered on October 2, 2017 when it was 9.20 au from the Sun. We started observing this comet with TS at the beginning of August 2019 when it was at 3.70 au. The comet made the closest approach to the Earth on December 28, 2019 at a distance of 1.52 au and it passed the perihelion on May 4, 2020 at 1.61 au. The water production rate of the comet reached a maximum of (4,27±0,12)10<sup>28 </sup>molecules/s and its dust production rate (A(0)fp(RC)) also reached the peak of 5110±25 cm on January 26, 2020, when the comet was at 2.08 au from the Sun (-100 days pre-perihelion). At the time of writing, we still monitoring the activity of the comet with TN at heliocentric distance of 1.70 au. Our observations show that C/2017 T2 is a normal LPC.</p> <p><strong>C/2018 Y1 (Iwamoto)</strong> is a nearly parabolic comet with a retrograde orbit discovered on December 18, 2018 by Japanese amateur astronomer Masayuki Iwamoto. We monitored the activity and composition of Iwamoto with both TN and TS telescopes from January to March 2019. The comet reached its maximum activity on January 29, 2019 when it was at 1.29 au from the Sun (-8 days pre-perihelion) with Q(H<sub>2</sub>O)=(1,68±0,05)10<sup>28 </sup>molecules/s and A(0)fp(RC)= 92±5 cm. These measurements show that it was a dust-poor comet compared to the typical LPCs.</p> <p><strong>C/2018 W2 (Africano) </strong>was discovered on November 27, 2018 at Mount Lemmon Survey with a visual magnitude of 20. The comet reached its perihelion on September 6, 2019 when it was at 1.45 au from the Sun. We monitored the comet from July 2019 (r<sub>h</sub>=1.71 au) to January 2020 (r<sub>h</sub>=2.18 au) with both TN and TS telescopes. The comet reached its maximum activity on September 21, 15 days post-perihelion (r<sub>h</sub>=1.47 au) with Q(H<sub>2</sub>O)=(0,40±0,03)10<sup>28 </sup>molecules/s.</p> <p><strong>C/2019 Y4 (ATLAS)</strong> is a comet with a nearly parabolic orbit discovered on December 18, 2019 by the ATLAS survey. We started to follow its activity and composition with broad- and narrow-band filters with the TN telescope on February 22, 2019 when it was at 1.32 au from the Sun until May 3, 2020 when the comet was at a heliocentric distance of 0.90 au inbound. The comet activity reached a maximum on March 22 (r<sub>h</sub>=1.65 au) 70 days before perihelion. At that time, the water-production rate reached (1,53±0,04)10<sup>28 </sup>molecules/s and the A(0)fp reached (1096±14) cm in the red filter. After that, the comet began to fade and disintegrated into several fragments.</p>

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