EXO 2030+375

Other Names

• V2246 Cyg (SIMBAD)

Monitoring Data:

Fermi/GBM Swift/BAT MAXI BeXRB-Monitor

General Characteristics

• Discovered 1985 by EXOSAT ()
• Optical companion: B0 Ve ()
• Distance: [math]\displaystyle{ 7.1,\text{kpc} }[/math] ()
• Very reliable Type I outburst at around ~100 mCrab over 10-20 days ()
• Three giant outburst to far stretching several months each: 1986, 2006 & 2021
• Kozai-Lidov oscillations in the Be-disk as possible driver of giant outbursts )
• ~0.2 Hz QPO () with luminosity dependent frequency ()

Orbital Parameters

• Orbital period: [math]\displaystyle{ P_{\text{Orb}} = 46.0211(3)\,\text{d} }[/math] ()
• Epoch of periastron passage: [math]\displaystyle{ T_0 = 52802.20(1)\,\text d }[/math] ()
• Projected semimajor axis:[math]\displaystyle{ a_{\text x}\sin i = 248(12)\,\text{lt-s} }[/math] ()
• Eccentricity:[math]\displaystyle{ e = 0. 0.409(1) }[/math] ()
• Longitude of periastron: [math]\displaystyle{ \omega = 212.0(4)^{\circ} }[/math] ()

Pulsations

• Pulse profiles strongly luminosity dependent: (,)
  • Two main peaks, one dominant at high and one at low luminosities
  • Interpreted as switch from pencil- to fan-beam pattern
  • One prominent and stable dip in pulse profile
  • Another very sharp dip one at specific luminosity
• Pulse profile evolution similar between outbursts

Figure taken from

Spectral Analysis

• Partially covered cutoffpl + black-body + neutral and ionized Iron lines
• Also fitted with BW07 ()
• Spectrum becomes harder with luminosity at lower luminosity and softer at higher luminosity ()
• Strong spectral changes with orbital phase:
  • Accretion curtail with increased NH and [math]\displaystyle{ \Delta \Gamma = 1.2 }[/math] (,)

Possible Cyclotron Features

• During Type I outburst ~36 keV ()
• During 2006 giant outburst ~11 keV ()
• During 2006 giant outburst ~63 keV ()

None of those is conclusively detected ()

References