arXiv subjects

David Boyd

Publications and source records attributed to David Boyd.

60 records · Page 4Linked to original sources

arXiv2007

Analysis of the first confirmed superoutburst of V337 Cygni in 2006 May

During 2006 May the first confirmed superoutburst of the dwarf nova V337 Cygni was observed using unfiltered CCD photometry. The outburst reached a peak magnitude of 15.2 on May 22 and lasted 13 days before the object returned to quiescence at around magnitude 20. Time-series photometry revealed superhumps with a period of 0.07012 +/- 0.00033d and amplitude 0.1 magnitude, thereby establishing for the first time its UGSU classification. Astrometry of V337 Cyg in outburst determined an accurate position and enabled the identity of the star in quiescence to be confirmed.

astro-ph↗

arXiv2006

Determination of the superhump period of the dwarf nova V701 Tau during the 2005 December superoutburst

We report new measurements of the superhump period of the UGSU-type dwarf nova V701 Tau during the 2005 December superoutburst. Using unfiltered time series CCD observations on 3 nights, we determine a probable superhump period Psh = 0.0690, plus or minus 0.0002d, but note that our data also permit a possible shorter period of 0.0663, plus or minus 0.0002d. The longer period agrees with the value measured during the first recorded superoutburst in 1995.

astro-ph↗

arXiv2006

CCD photometry and visual observations of V1663 Aquilae (Nova Aquilae 2005)

We present CCD V and I band photometry and visual observations of V1663 Aquilae (Nova Aquilae 2005). This was a classical fast nova, probably of type Ba, observed for the first time on 2005 June 9. Maximum light occurred at HJD= 2453531.2 +/- 0.2, when the apparent V magnitude was 10.7 +/- 0.1 and the V-I colour index 3.1. Decline times were t2,V= 17d, t2,I= 18d, t3,V= 32d and t3,I= 35d. We derived a maximum absolute V magnitude of -7.8 +/- 0.2, colour excess E(B-V)= 2, extinction AV= 6 magnitudes and distance d= 2.9 +/- 0.4 kpc. After maximum the V-I colour index remained between 3.1 and 3.4 for 50 days, then gradually reduced as the nova became bluer with increasing age. We saw no direct evidence of dust emission although this could have contributed to the high extinction in the direction of the nova.

astro-ph↗

arXiv2006

Brief outbursts in the dwarf nova V1316 Cygni

Several brief outbursts were detected in the dwarf nova V1316 Cyg during 2005. These events have an average amplitude of 1.4 magnitude and a duration of <1 to 2 days. Whilst no outburst period could be confirmed, the shortest period between detected events is 10 days. These curious brief outbursts appear to be the normal pattern of behaviour for this system. They are of smaller amplitude and shorter duration than normal outbursts previously reported in this star. V1316 Cyg appears to be a very unusual system and we suggest that further observations by both amateur and professional astronomers could yield important information about the underlying mechanism.

astro-ph↗

arXiv2006

Measurement of the orbital and superhump periods of the eclipsing cataclysmic variable SDSS J170213.26+322954.1

The orbital period of the eclipsing cataclysmic variable SDSS J170213.26+322954.1 has been measured as 0.10008215+/-0.00000001d using observations of eclipses during the first recorded superoutburst in October 2005 together with eclipses observed in quiescence in July 2003. This period puts the system in the centre of the period gap. Observation of superhumps during the October 2005 outburst with a period of 0.10496+/-0.00015d confirms this to be a UGSU-type system with a period excess of 4.9%.

astro-ph↗

arXiv2004

Detection and measurement in the V-band of the white dwarf spin period in the January 2004 outburst of DO (YY) Draconis

A modulation in the V-band with period 527.84+/-1.81 sec and amplitude 0.023 magnitude, attributable to the spin of the magnetic white dwarf primary star, has been detected in 7.5 hours of V-band CCD photometry data recorded during the January 2004 outburst of the DQ Her type dwarf nova DO (YY) Draconis. This measurement is consistent with previous results for the white dwarf spin period based on X-ray and UV observations made with the Hubble Space Telescope, ROSAT and the Rossi X-ray Timing Explorer and appears to be the first independent determination of the spin period in the V-band. It is consistent with previous V-band observations in not showing a significant signal at the first harmonic of the spin period as seen in X-ray and UV data. Light output in the V-band peaks only once per rotation of the white dwarf rather than twice as seen in X-rays and UV. Concurrent observation at optical and X-ray wavelengths is needed to establish whether these two modulation behaviours occur at the same time during the outburst and to investigate the phase relationship between them. A coordinated observing campaign at a future outburst would help to advance our understanding of this system.

astro-ph↗