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So far NOAHelmos2Admin has created 14 blog entries.

3D MHD astrospheres: applications to IRC-10414 and Betelgeuse

By |2021-07-17T12:35:25+03:00July 12th, 2021|

A significative fraction of all massive stars in the Milky Way move supersonically through their local interstellar medium (ISM), producing bow shock nebulae by wind-ISM interaction. The stability of these observed astrospheres around cool massive stars challenges precedent two-dimensional (magneto-)hydrodynamical simulations of their surroundings. We present three-dimensional magneto-hydrodynamical (3D MHD) simulations of the circumstellar medium of runaway M-type red supergiant stars moving with velocity v* = 50 km s−1 . We treat the stellar wind with ...

Call for proposals – 2021

By |2021-07-20T01:04:17+03:00April 10th, 2021|

Call for proposals - 2021 Proposal deadline for the observing period July 1- October 31, 2021 was May 7, 2021 (23:59 Local Time). How to apply In order to apply for time to use the Aristarchos telescope please fill out the application form. Applications for observation time can only [...]

‘Ears’ formation in supernova remnants: overhearing an interaction history with bipolar circumstellar structures

By |2021-07-16T03:40:17+03:00April 1st, 2021|

A characteristic feature that is frequently found in nearby supernova remnants (SNRs) is the existence of two antisymmetric, local protrusions that are projected as two 'ears' in the morphology of the nebula. In this paper, we present a novel scenario for the 'ear' formation process,

Aristarchos Telescope Participates in the Optical Radionet Pilot (ORP) Program

By |2021-07-23T17:43:45+03:00March 23rd, 2021|

Aristarchos Telescope Participates in the Optical Radionet Pilot (ORP) Program First meeting of the Board of Directors of the new Optical Radionet Pilot program Aristarchos telescope participates in an international network of astronomical stations in the Optical Radionet Pilot program's framework to strengthen the research in Observational Astronomy. The director [...]

Edge-on boxes with X-features as parts of galactic bars – NGC 352: A direct piece of observational evidence

By |2021-07-16T03:51:20+03:00March 1st, 2021|

This paper is a contribution to the discussion about whether the X/peanut component is part of the bar, or the bar itself. Our goal is to present a clear-cut case of a barred-spiral galaxy in which all structural components (i.e. the thick and thin part of the bar and the spiral arms) can be observed in its image and their dimensions directly measured there. We obtained deep images of the nearby galaxy NGC 352, which has an ideal inclination allowing us to observe all of the parts that compose its morphology, estimate their relative sizes, and determine the topology of the luminous matter...

CoBiToM project – I. Contact binaries towards merging

By |2021-07-16T03:43:23+03:00January 29th, 2021|

Binary and multiple stellar systems are numerous in our solar neighbourhood with 80 per cent of the solar-type stars being members of systems with high order multiplicity. The Contact Binaries Towards Merging (CoBiToM) Project is a programme that focuses on contact binaries and multiple stellar systems, as a key for understanding stellar nature. The goal is to investigate stellar coalescence and merging processes, as the final state of stellar evolution of low-mass contact binary systems. Obtaining observational data of approximately 100 eclipsing binaries and multiple systems and more than 400 archival systems, the programme aspires to give insights for their physical and orbital parameters and their temporal variations, e.g. the orbital period ...

Asteroseismology of two Kepler detached eclipsing binaries

By |2021-07-16T03:51:02+03:00October 9th, 2020|

The present work contains light curve, spectroscopic, and asteroseismic analyses for KIC 04851217 and KIC 10686876. These systems are detached eclipsing binaries hosting a pulsating component of δ Scuti type and have been observed with the unprecedented accuracy of the Kepler space telescope. Using ground-based spectroscopic observations, the spectral types of the primary components of the systems were estimated as A6V and A5V for KIC 04851217 and KIC 10686876, respectively, with an uncertainty of one subclass. The present spectral classification, together with literature radial velocity curves, were used to model the light curves of the systems and, therefore, to calculate the absolute parameters of their ...

Two new nova shells associated with V4362 Sagittarii and DO Aquilae

By |2021-07-16T03:45:52+03:00September 21st, 2020|

A classical nova is an eruption on the surface of a white dwarf in an accreting binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell. The shaping mechanisms of nova shells are probes of the processes that take place at energy scales between planetary nebulae and supernova remnants. We report on the discovery of nova shells surrounding the ...

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