scholarly journals Near-Earth asteroids spectroscopic survey at Isaac Newton Telescope

2019 ◽  
Vol 627 ◽  
pp. A124 ◽  
Author(s):  
M. Popescu ◽  
O. Vaduvescu ◽  
J. de León ◽  
R. M. Gherase ◽  
J. Licandro ◽  
...  
Keyword(s):  
Radiation Effects ◽  
Practical Reasons ◽  
Main Process ◽  
Absolute Deviation ◽  
Orbital Parameters ◽  
Isaac Newton ◽  
General Terms ◽  
Isaac Newton Telescope ◽  
C Complex ◽  
Near Earth Asteroids

Context. The population of near-Earth asteroids (NEAs) shows a large variety of objects in terms of physical and dynamical properties. They are subject to planetary encounters and to strong solar wind and radiation effects. Their study is also motivated by practical reasons regarding space exploration and long-term probability of impact with the Earth. Aims. We aim to spectrally characterize a significant sample of NEAs with sizes in the range of ~0.25–5.5 km (categorized as large), and search for connections between their spectral types and the orbital parameters. Methods. Optical spectra of NEAs were obtained using the Isaac Newton Telescope (INT) equipped with the IDS spectrograph. These observations are analyzed using taxonomic classification and by comparison with laboratory spectra of meteorites. Results. A total number of 76 NEAs were observed. We spectrally classified 44 of them as Q/S-complex, 16 as B/C-complex, eight as V-types, and another eight belong to the remaining taxonomic classes. Our sample contains 27 asteroids categorized as potentially hazardous and 31 possible targets for space missions including (459872) 2014 EK24, (436724) 2011 UW158, and (67367) 2000 LY27. The spectral data corresponding to (276049) 2002 CE26 and (385186) 1994 AW1 shows the 0.7 μm feature which indicates the presence of hydrated minerals on their surface. We report that Q-types have the lowest perihelia (a median value and absolute deviation of 0.797 ± 0.244 AU) and are systematically larger than the S-type asteroids observed in our sample. We explain these observational evidences by thermal fatigue fragmentation as the main process for the rejuvenation of NEA surfaces. Conclusions. In general terms, the taxonomic distribution of our sample is similar to the previous studies and matches the broad groups of the inner main belt asteroids. Nevertheless, we found a wide diversity of spectra compared to the standard taxonomic types.

scholarly journals 280 one-opposition near-Earth asteroids recovered by the EURONEAR with the Isaac Newton Telescope

2018 ◽  
Vol 609 ◽  
pp. A105 ◽  
Author(s):  
O. Vaduvescu ◽  
L. Hudin ◽  
T. Mocnik ◽  
F. Char ◽  
A. Sonka ◽  
...  
Keyword(s):  
Moving Objects ◽  
Wide Field ◽  
Minor Planets ◽  
Main Belt ◽  
Isaac Newton ◽  
Isaac Newton Telescope ◽  
Fast Motion ◽  
The One ◽  
Near Earth Asteroids

Context. One-opposition near-Earth asteroids (NEAs) are growing in number, and they must be recovered to prevent loss and mismatch risk, and to improve their orbits, as they are likely to be too faint for detection in shallow surveys at future apparitions. Aims. We aimed to recover more than half of the one-opposition NEAs recommended for observations by the Minor Planet Center (MPC) using the Isaac Newton Telescope (INT) in soft-override mode and some fractions of available D-nights. During about 130 h in total between 2013 and 2016, we targeted 368 NEAs, among which 56 potentially hazardous asteroids (PHAs), observing 437 INT Wide Field Camera (WFC) fields and recovering 280 NEAs (76% of all targets). Methods. Engaging a core team of about ten students and amateurs, we used the THELI, Astrometrica, and the Find_Orb software to identify all moving objects using the blink and track-and-stack method for the faintest targets and plotting the positional uncertainty ellipse from NEODyS. Results. Most targets and recovered objects had apparent magnitudes centered around V ~ 22.8 mag, with some becoming as faint as V ~ 24 mag. One hundred and three objects (representing 28% of all targets) were recovered by EURONEAR alone by Aug. 2017. Orbital arcs were prolonged typically from a few weeks to a few years; our oldest recoveries reach 16 years. The O−C residuals for our 1854 NEA astrometric positions show that most measurements cluster closely around the origin. In addition to the recovered NEAs, 22 000 positions of about 3500 known minor planets and another 10 000 observations of about 1500 unknown objects (mostly main-belt objects) were promptly reported to the MPC by our team. Four new NEAs were discovered serendipitously in the analyzed fields and were promptly secured with the INT and other telescopes, while two more NEAs were lost due to extremely fast motion and lack of rapid follow-up time. They increase the counting to nine NEAs discovered by the EURONEAR in 2014 and 2015. Conclusions. Targeted projects to recover one-opposition NEAs are efficient in override access, especially using at least two-meter class and preferably larger field telescopes located in good sites, which appear even more efficient than the existing surveys.

The Isaac Newton Telescope Wide Field Camera survey of the Monoceros Ring: accretion origin or Galactic anomaly?

2005 ◽  
Vol 362 (2) ◽  
pp. 475-488 ◽  
Author(s):  
Blair C. Conn ◽  
Geraint F. Lewis ◽  
Mike J. Irwin ◽  
Rodrigo A. Ibata ◽  
Annette M. N. Ferguson ◽  
...  
Keyword(s):  
Wide Field ◽  
Isaac Newton ◽  
Isaac Newton Telescope

scholarly journals The La Palma Data Archive

1989 ◽  
Vol 110 ◽  
pp. 139-140
Author(s):  
Chris Benn
Keyword(s):  
Data Archive ◽  
Isaac Newton ◽  
La Palma ◽  
Data Archives ◽  
International Ultraviolet Explorer ◽  
Isaac Newton Telescope ◽  
The Republic ◽  
Volcanic Caldera ◽  
The Uk ◽  
William Herschel

The Observatorio del Roque de los Muchachos is perched atop a volcanic caldera on the island of La Palma in the Canary Islands, 400 km off the coast of North Africa. Three of the telescopes at the observatory are products of a collaboration between the UK, the Netherlands, Spain and the Republic of Ireland. They are the 1.0-m Jacobus Kapteyn Telescope, the 2.5-m Isaac Newton Telescope and the 4.2-m William Herschel Telescope (which saw first light in July 1987)1. The telescopes are computer controlled (running under ADAM software), and the observations are recorded primarily in electronic form. Recognising the success of astronomical-satellite data archives, such as that generated by the International Ultraviolet Explorer, a La Palma Data Archive has been established at the Royal Greenwich Observatory. The archive will be used by astronomers wishing to exploit data obtained by other observers, by engineers interested in the performance of telescope and instruments under varying conditions, and for monitoring the way in which the telescope is used.

scholarly journals Low Resolution Spectroscopy of 13 Low Surface Brightness PN's

1989 ◽  
Vol 131 ◽  
pp. 220-220
Author(s):  
A. Manchado ◽  
S. R. Pottasch ◽  
A. Mampaso
Keyword(s):  
Surface Brightness ◽  
Photon Counting ◽  
Outer Part ◽  
Low Resolution ◽  
Counting System ◽  
Isaac Newton ◽  
La Palma ◽  
Ionization Structure ◽  
Low Surface Brightness ◽  
Isaac Newton Telescope

We have obtained long-slit low resolution spectra (7.5 A resolution) of a sample of 13 low surface brightness planetary nebulae using the 2.5-m Isaac Newton Telescope (La Palma) with the Image Photon Counting System (IPCS) covering a spectral range from 3300 A to 7300 A. From those spectra we calculated the ionic and total abundances of 0, N, Ne and Ar. Variations in the ionization structure between the inner and the outer part are found in some nebulae although the total abundances appear not to change significantly along the nebulae.

Statistical analysis of asteroid taxonomic signatures from magnitude phase function

2020 ◽  
Author(s):  
Zhong-Yi Lin ◽  
Chung-Chien Cheng ◽  
Chan-Kao Chang ◽  
Wei-Ling Tseng ◽  
Wing-Huen Ip
Keyword(s):  
Statistical Analysis ◽  
Size Distribution ◽  
Spectral Type ◽  
Phase Function ◽  
Observational Bias ◽  
G Value ◽  
C Complex ◽  
Taxonomic Groups ◽  
Near Earth Asteroids

<p>According the H-G magnitude system ,this work using the known spectral-type asteroids (about three hundreds asteroids including MBAs and NEAs) found from literature, we derived the new G-value of two main taxonomic groups in both g and r filters (In g filter, C-type is 0.095±0.112, and S-type is 0.257±0.165. In r filter, C-type is 0.091±0.134, and S-type is 0.280±0.158). We then used these values to identify the unknown taxonomic near-Earth asteroids(NEAs) obtained by (ZTF) from June 2018 to May 2020. In total, more than one hundred NEAs had been classified into C- and S-complex. In addition, the investigation of size distribution in NEAs found that the C-complex asteroids are relatively larger than S-complex asteroids, probably due to observational bias (albedo).</p>

scholarly journals Co-ordinated Optical and Radio Observations of Symbiotic Stars

1990 ◽  
Vol 122 ◽  
pp. 442-443
Author(s):  
R. J. Ivison ◽  
M. F. Bode ◽  
J. Meaburn ◽  
R. J. Davis ◽  
R. F. Nelson ◽  
...  
Keyword(s):  
Broad Band ◽  
Symbiotic Stars ◽  
Echelle Spectrograph ◽  
Type Region ◽  
Isaac Newton ◽  
La Palma ◽  
Circumstellar Extinction ◽  
Optical Line ◽  
Isaac Newton Telescope ◽  
5 Ghz

AbstractWe present preliminary results from absolutely flux-calibrated optical spectroscopy, together with 5 GHz radio flux measures of 17 symbiotic stars. The data were obtained quasi-simultaneously using the Manchester Echelle Spectrograph on the Isaac Newton Telescope, La Palma between 1988 September 20 and 24, and the Broad Band Interferometer at Jodrell Bank during 1988 October. This represents the largest sample of these stars observed in this way to date. Distances are calculated using visual extinctions and are compared with other quoted values. In general, the agreement is surprisingly good. Plots of individual line luminosities vs. radio luminosity indicate that the D-type (dusty) symbiotics (both also proto-planetary nebulae) have far higher radio luminosities than S-types (stellar) for comparable recombination and forbidden line luminosities. This may however be due to underestimation of optical line luminosities for the D-types as the circumstellar extinction contribution is uncertain. The single D’-type (cool dust, yellow secondary) lies at the low luminosity end of the S-type region. ‘Very slow novae’ in our sample lie in both groups.

scholarly journals Planetary nebulae with Wolf–Rayet-type central stars – I. The case of the high-excitation NGC 2371

2020 ◽  
Vol 496 (1) ◽  
pp. 959-973
Author(s):  
V M A Gómez-González ◽  
J A Toalá ◽  
M A Guerrero ◽  
H Todt ◽  
L Sabin ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Planetary Nebula ◽  
Symmetry Axis ◽  
High Excitation ◽  
Central Cavity ◽  
Isaac Newton ◽  
Double Structure ◽  
High Ionization ◽  
Isaac Newton Telescope ◽  
Central Stars

ABSTRACT We present the analysis of the planetary nebula (PN) NGC 2371 around the [Wolf–Rayet] (WR) star WD 0722+295. Our Isaac Newton Telescope intermediate dispersion spectrograph spectra, in conjunction with archival optical and ultraviolet images, unveil in unprecedented detail the high ionization of NGC 2371. The nebula has an apparent multipolar morphology, with two pairs of lobes protruding from a barrel-like central cavity, a pair of dense low ionization knots misaligned with the symmetry axis embedded within the central cavity, and a high-excitation halo mainly detected in He ii. The abundances from the barrel-like central cavity and dense knots agree with abundance determinations for other PNe with [WR]-type central stars of PNe. We suggest that the densest knots inside NGC 2371 are the oldest structures, remnant of a dense equatorial structure, while the main nebular shell and outer lobes resulted from a latter ejection that ended the stellar evolution. The analysis of position–velocity diagrams produced from our high-quality spectra suggests that NGC 2371 has a bipolar shape with each lobe presenting a double structure protruding from a barrel-like central region. The analysis of the spectra of WD 0722+295 results in similar stellar parameters as previously reported. We corroborate that the spectral subtype corresponds with a [WO1] type.

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