19 research outputs found
Speckle Interferometry with CMOS Detector
In 2022 we carried out an upgrade of the speckle polarimeter (SPP) -- the
facility instrument of the 2.5-m telescope of the Caucasian Observatory of the
SAI MSU. During the overhaul, CMOS Hamamatsu ORCA-Quest qCMOS C15550-20UP was
installed as the main detector, some drawback of the previous version of the
instrument were eliminated. In this paper, we present a description of the
instrument, as well as study some features of the CMOS detector and ways to
take them into account in speckle interferometric processing. Quantitative
comparison of CMOS and EMCCD in the context of speckle interferometry is
performed using numerical simulation of the detection process. Speckle
interferometric observations of 25 young variable stars are given as an example
of astronomical result. It was found that BM And is a binary system with a
separation of 273 mas. The variability of the system is dominated by the
brightness variations of the main component. A binary system was also found in
NSV 16694 (TYC 120-876-1). The separation of this system is 202 mas.Comment: 24 pages, 27 figures. Minor style differences with respect to version
accepted to Astrophys. Bull. V. 78, no.
Photometry and spectroscopy of the luminous red nova PSNJ14021678+5426205 in the galaxy M101
© 2016, Pleiades Publishing, Ltd.We present the results of the study of a red nova from the observations carried out with the Russian 6-m telescope (BTA) along with other telescopes of SAO RAS and SAI MSU. To investigate the nova progenitor,we used the data from the Digital Sky Survey and amateur photos available on the Internet. In the period between April 1993 and July 2014, the brightness of the progenitor gradually increased by (Formula presented.) in the V-band. At the peak of the first outburst in mid-November 2014, the star reached an absolute visual magnitude of (Formula presented.) but was discovered later, in February 2015, in a repeated outburst at the magnitude of (Formula presented.). The amplitude of the outburst was minimum among the red novae, only (Formula presented.) in V-band. The Hα emission line and the background of a cool supergiant continuum with gradually decreasing surface temperature were observed in the spectra. Such process is typical for red novae, although the object under study showed extreme parameters: maximum luminosity, maximum outburst duration, minimum outburst amplitude, unusual shape of the light curve. This event is interpreted as a massive OB star system components’merging accompanied by formation of a common envelope and then the expansion of this envelope with minimal energy losses
The GAPS programme at TNG XLIX. TOI-5398, the youngest compact multi-planet system composed of an inner sub-Neptune and an outer warm Saturn
Short-period giant planets are frequently found to be solitary compared to
other classes of exoplanets. Small inner companions to giant planets with 15 days are known only in five compact systems: WASP-47, Kepler-730,
WASP-132, TOI-1130, and TOI-2000. Here, we report the confirmation of TOI-5398,
the youngest compact multi-planet system composed of a hot sub-Neptune
(TOI-5398 c, = 4.77271 days) orbiting interior to a short-period
Saturn (TOI-5398 b, = 10.590547 days) planet, both transiting
around a 650 150 Myr G-type star. As part of the GAPS Young Object
project, we confirmed and characterised this compact system, measuring the
radius and mass of both planets, thus constraining their bulk composition.
Using multidimensional Gaussian processes, we simultaneously modelled stellar
activity and planetary signals from TESS Sector 48 light curve and our HARPS-N
radial velocity time series. We have confirmed the planetary nature of both
planets, TOI-5398 b and TOI-5398 c, alongside a precise estimation of stellar
parameters. Through the use of astrometric, photometric, and spectroscopic
observations, our findings indicate that TOI-5398 is a young, active G dwarf
star (650 150 Myr), with a rotational period of = 7.34
days. The transit photometry and radial velocity measurements enabled us to
measure both the radius and mass of planets b, ,
, and c, , . TESS observed TOI-5398 during sector 48 and no further
observations are planned in the current Extended Mission, making our
ground-based light curves crucial for ephemeris improvement. With a
Transmission Spectroscopy Metric value of around 300, TOI-5398 b is the most
amenable warm giant (10 < < 100 days) for JWST atmospheric
characterisation.Comment: 29 pages, Paper accepted for publication in Astronomy & Astrophysic
The GAPS programme at TNG : XLIX. TOI-5398, the youngest compact multi-planet system composed of an inner sub-Neptune and an outer warm Saturn
Context. Short-period giant planets (P ≲ 10 days, Mp >0.1 MJ) are frequently found to be solitary compared to other classes of exo-planets. Small inner companions to giant planets with P ≲ 15 days are known only in five compact systems: WASP-47, Kepler-730, WASP-132, TOI-1130, and TOI-2000. Here, we report the confirmation of TOI-5398, the youngest known compact multi-planet system composed of a hot sub-Neptune (TOI-5398 c, Pc = 4.77271 days) orbiting interior to a short-period Saturn (TOI-5398 b, Pb = 10.590547 days) planet, both transiting around a 650 ± 150 Myr G-type star.
Aims. As part of the Global Architecture of Planetary Systems (GAPS) Young Object project, we confirmed and characterised this compact system, measuring the radius and mass of both planets, thus constraining their bulk composition.
Methods. Using multi-dimensional Gaussian processes, we simultaneously modelled stellar activity and planetary signals from the Transiting Exoplanet Survey Satellite (TESS) Sector 48 light curve and our High Accuracy Radial velocity Planet Searcher (HARPS-N) radial velocity (RV) time series. We confirmed the planetary nature of both planets, TOI-5398 b and TOI-5398 c, and obtained a precise estimation of their stellar parameters.
Results. Through the use of astrometric, photometric, and spectroscopic observations, our findings indicate that TOI-5398 is a young, active G dwarf star (650 ± 150 Myr) with a rotational period of Prot = 7.34 days. The transit photometry and RV measurements enabled us to measure both the radius and mass of planets b, Rb = 10.30 ± 0.40 R⊕, Mb = 58.7 ± 5.7 M⊕, and c, Rc = 3.52 ± 0.19 R⊕, Mc = 11.8 ± 4.8 M⊕. TESS observed TOI-5398 during sector 48 and no further observations are planned in the current Extended Mission, making our ground-based light curves crucial for improvement of the ephemeris. With a transmission spectroscopy metric (TSM) value of around 300, TOI-5398 b is the most amenable warm giant (10 < P < 100 days) for JWST atmospheric characterisation
Photometry and spectroscopy of the luminous red nova PSNJ14021678+5426205 in the galaxy M101
© 2016, Pleiades Publishing, Ltd.We present the results of the study of a red nova from the observations carried out with the Russian 6-m telescope (BTA) along with other telescopes of SAO RAS and SAI MSU. To investigate the nova progenitor,we used the data from the Digital Sky Survey and amateur photos available on the Internet. In the period between April 1993 and July 2014, the brightness of the progenitor gradually increased by (Formula presented.) in the V-band. At the peak of the first outburst in mid-November 2014, the star reached an absolute visual magnitude of (Formula presented.) but was discovered later, in February 2015, in a repeated outburst at the magnitude of (Formula presented.). The amplitude of the outburst was minimum among the red novae, only (Formula presented.) in V-band. The Hα emission line and the background of a cool supergiant continuum with gradually decreasing surface temperature were observed in the spectra. Such process is typical for red novae, although the object under study showed extreme parameters: maximum luminosity, maximum outburst duration, minimum outburst amplitude, unusual shape of the light curve. This event is interpreted as a massive OB star system components’merging accompanied by formation of a common envelope and then the expansion of this envelope with minimal energy losses
Photometry and spectroscopy of the luminous red nova PSNJ14021678+5426205 in the galaxy M101
© 2016, Pleiades Publishing, Ltd.We present the results of the study of a red nova from the observations carried out with the Russian 6-m telescope (BTA) along with other telescopes of SAO RAS and SAI MSU. To investigate the nova progenitor,we used the data from the Digital Sky Survey and amateur photos available on the Internet. In the period between April 1993 and July 2014, the brightness of the progenitor gradually increased by (Formula presented.) in the V-band. At the peak of the first outburst in mid-November 2014, the star reached an absolute visual magnitude of (Formula presented.) but was discovered later, in February 2015, in a repeated outburst at the magnitude of (Formula presented.). The amplitude of the outburst was minimum among the red novae, only (Formula presented.) in V-band. The Hα emission line and the background of a cool supergiant continuum with gradually decreasing surface temperature were observed in the spectra. Such process is typical for red novae, although the object under study showed extreme parameters: maximum luminosity, maximum outburst duration, minimum outburst amplitude, unusual shape of the light curve. This event is interpreted as a massive OB star system components’merging accompanied by formation of a common envelope and then the expansion of this envelope with minimal energy losses
Photometry and spectroscopy of the luminous red nova PSNJ14021678+5426205 in the galaxy M101
© 2016, Pleiades Publishing, Ltd.We present the results of the study of a red nova from the observations carried out with the Russian 6-m telescope (BTA) along with other telescopes of SAO RAS and SAI MSU. To investigate the nova progenitor,we used the data from the Digital Sky Survey and amateur photos available on the Internet. In the period between April 1993 and July 2014, the brightness of the progenitor gradually increased by (Formula presented.) in the V-band. At the peak of the first outburst in mid-November 2014, the star reached an absolute visual magnitude of (Formula presented.) but was discovered later, in February 2015, in a repeated outburst at the magnitude of (Formula presented.). The amplitude of the outburst was minimum among the red novae, only (Formula presented.) in V-band. The Hα emission line and the background of a cool supergiant continuum with gradually decreasing surface temperature were observed in the spectra. Such process is typical for red novae, although the object under study showed extreme parameters: maximum luminosity, maximum outburst duration, minimum outburst amplitude, unusual shape of the light curve. This event is interpreted as a massive OB star system components’merging accompanied by formation of a common envelope and then the expansion of this envelope with minimal energy losses