USNO-A2.0 0825-18396733

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Double star
USNO-A2.0 0825-18396733
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Right ascension 20 h 31 m 37.59 s
declination -00 ° 05 ′ 11.2 ″
Typing
Spectral class M.
Astrometry
parallax 826  mas
distance 253  pc
Physical Properties
Other names
and catalog entries
Other names
  • DENIS J203137.5-000511
  • Gaia DR2 4229582917206160896
  • GSC2 S302012318289
  • GSC2.3 S9WB018289
  • USNO-B1.0 0899-00571732

According to current research, USNO-A2.0 0825-18396733 is a cataclysmically mutable binary star located in the constellation Eagle at a distance of 826 light years from Earth .

introduction

AM Herculis stars (English Polars, systematic abbreviation : AM ) represent a subclass of cataclysmically variable double stars (CVs) whose system consists of a white dwarf as the main component and a red dwarf as a minor component, whose Roche limit it fills. The special properties of AM Herculis stars are associated with a strong magnetic field of the white dwarf. This prevents the formation of an accretion disk and thus directs matter along the magnetic field lines to the magnetic poles of the white dwarf. The accretion column is one of the main sources of radiation in the optical and X-ray range, with the optical radiation from the poles being strongly polarized. The entire system has a mass similar to that of the sun, with the larger part of about 0.71 to 0.78 solar masses ( M ☉ for short ) falling on the white dwarf and the smaller part from just 0.18 to 0.20 M ☉ on the red dwarf.

history

USNO-A2.0 0825-18396733 ( USNO 0825 for short ) was found by a team of amateur astronomers when these photometric observations were made in a region in the constellation Eagle ( Latin Aquila ) in the northern summer and autumn skies using a SAO-RAS Zeiss -1000 telescope, with the polarimetry being carried out with the 6 m BTA telescope in the Russian Selentschuk Observatory . After the team had taken 98 pictures with an exposure time of 300 seconds without a filter, they then determined the system ephemeris with a value of HJD = 2455387.3976 (± 0.001) + 0.0840 (± 0.0004) E, where the zero phase corresponds to the time of minimum brightness.

The brightness of the system varies in the RC filter from 17: 5 to 20: 0, with the polarimetric observations of the object in the V filter showing a highly variable circular polarization from −2% to over −31%, which in turn means that the USNO- A2.0 0825-18396733 is a Cataclysmically Variable Double Star.

Individual evidence

  1. ↑ a b c Discovery and study of the new polar USNO-A2.0 0825-18396733. In: 1. Gabdeev MM, Borisov NV, Shimansky VV, Spiridonova OI, Spectral and Photometric Studies of the Polar USNO-A2.0 0825-18396733, 2015, Astronomy Reports, 59,3, 213-220 2. Afanasiev VL, Borisov NV, Gabdeev MM, Photometric and Polarimetric Observations of a New Polar USNO-A2.0 0825-18396733, 2015, Astrophysical Bulletin, 70, 3, 328-333. Accessed September 4, 2019 .
  2. ^ VL Afanasiev, NV Borisov and MM Gabdeev: Photometric and Polarimetric Observations of a New PolarUSNO-A2.0 0825-18396733 . In: Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz, 369167 Russia . May 6, 2015 ( springer.com [accessed September 5, 2019]).
  3. ↑ Spectral and photometric studies of the polar USNO-A2.0 0825-18396733. Retrieved September 5, 2019 .
  4. ↑ Photometric and Polarimetric Observations of a New Polar USNO-A2.0 0825-18396733. July 2015, accessed September 5, 2019 .
  5. ↑ Photometric and Polarimetric Observations of a New Polar USNO-A2.0 0825-18396733. Accessed September 4, 2019 .
  6. ↑ a b (PDF) Photometric and Polarimetric Observations of a New Polar USNO-A2.0 0825-18396733. Accessed September 4, 2019 .
  7. ↑ Шиманский В.в, Спиридонова О.и, Габдеев М.м, Борисов Н.в: СПЕКТРАЛЬНЫЕ И ФОТОМЕТРИЧЕСКИЕ ИССЛЕДОВАНИЯ ПОЛЯРА USNO-A2.0 0825-18396733 . In: Астрономический журнал . tape 92 , no. 3 , 2015, ISSN  0004-6299 ( naukarus.com [accessed September 4, 2019]).
  8. ↑ USNOA2 0825-18396733 - Star - SKY-MAP. Retrieved September 4, 2019 .

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