The horns of the dilemma: obesity, pregnancy and the broken social contract with today's adolescents
The horns of the dilemma: obesity, pregnancy and the broken social contract with today's adolescents
Changes in the supercycle lengths of some SU UMa-type dwarf novae have been detected by other studies, and indicate that the mass transfer rates noticeably decrease over time. We investigated the supercycle lengths of three SU UMa-type dwarf novae: AR Pic, QW Ser, and V521 Peg, to determine if they have detectable changes in their supercycles. We present the results of optical spectroscopic and photometric observations of these sources. Our observations were conducted in 2016 and 2017 at the Boyden Observatory and the Sutherland station of the South African Astronomical Observatory. The quiescent results indicated that all three sources are typical SU UMa-type dwarf novae. We also present results of AR Pic and QW Ser in outburst and of V521 Peg during a precursor outburst and superoutburst. Light curves were supplemented by the Catalina Real-Time Transient Survey, the ASAS-3 and ASAS-SN archives, and the AAVSO International Database in order to investigate the long-term behaviour of these sources. Our results combined with catalogued properties for all short-period dwarf novae show a possible relationship between the supercycle time in SU UMa systems and their orbital periods, which is interpreted as the decline in the mass transfer rate as systems evolve towards and away from the ‘period minimum’. At the shortest orbital periods, SU UMa systems are almost indistinguishable from WZ Sge systems. However, we propose that the scaleheight between the secondary’s photosphere and L1 may be a factor that distinguish the SU UMa subclasses.
Hanson, Mark
1952fad1-abc7-4284-a0bc-a7eb31f70a3f
Hanson, Mark
1952fad1-abc7-4284-a0bc-a7eb31f70a3f
Hanson, Mark
(2022)
The horns of the dilemma: obesity, pregnancy and the broken social contract with today's adolescents.
Obesity.
(Submitted)
Abstract
Changes in the supercycle lengths of some SU UMa-type dwarf novae have been detected by other studies, and indicate that the mass transfer rates noticeably decrease over time. We investigated the supercycle lengths of three SU UMa-type dwarf novae: AR Pic, QW Ser, and V521 Peg, to determine if they have detectable changes in their supercycles. We present the results of optical spectroscopic and photometric observations of these sources. Our observations were conducted in 2016 and 2017 at the Boyden Observatory and the Sutherland station of the South African Astronomical Observatory. The quiescent results indicated that all three sources are typical SU UMa-type dwarf novae. We also present results of AR Pic and QW Ser in outburst and of V521 Peg during a precursor outburst and superoutburst. Light curves were supplemented by the Catalina Real-Time Transient Survey, the ASAS-3 and ASAS-SN archives, and the AAVSO International Database in order to investigate the long-term behaviour of these sources. Our results combined with catalogued properties for all short-period dwarf novae show a possible relationship between the supercycle time in SU UMa systems and their orbital periods, which is interpreted as the decline in the mass transfer rate as systems evolve towards and away from the ‘period minimum’. At the shortest orbital periods, SU UMa systems are almost indistinguishable from WZ Sge systems. However, we propose that the scaleheight between the secondary’s photosphere and L1 may be a factor that distinguish the SU UMa subclasses.
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Submitted date: 25 April 2022
Identifiers
Local EPrints ID: 467666
URI: http://eprints.soton.ac.uk/id/eprint/467666
ISSN: 1930-7381
PURE UUID: 1c34e304-4bf5-4ec7-a46d-6b87572c187a
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Date deposited: 18 Jul 2022 18:23
Last modified: 14 Mar 2024 02:44
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