The 2001 superoutburst of WZ sagittae

Joseph Patterson, Gianluca Masi, Michael W. Richmond, Brian Martin, Edward C Beshore, David R. Skillman, Jonathan Kemp, Tonny Vanmunster, Robert Rea, William Allen, Stacey Davis, Tracy Davis, Arne A. Henden, Donn Starkey, Jerry Foote, Arto Oksanen, Lewis M. Cook, Robert E. Fried, Dieter Husar, Rudolf Novák & 8 others Tut Campbell, Jeff Robertson, Thomas Krajci, Elena Pavlenko, Nestor Mirabal, Panos G. Niarchos, Orville Brettman, Stan Walker

Research output: Contribution to journalArticle

  • 126 Citations

Abstract

We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V = 15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ∼1 mag amplitude and 2 day recurrence time; these "echo outbursts" are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence. Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: A strong orbital signal dominated the first 12 days, followed by a powerful common superhump at 0.05721(5) day, 0.92(8)% longer than Porb. The latter endured for at least 90 days, although probably mutating into a "late" superhump with a slightly longer mean period [0.05736(5) day]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: The orbital frequency ωo and an unseen low frequency Ω, believed to represent the accretion disk's apsidal precession. Long time series reveal an intricate fine structure, with ∼20 incommensurate frequencies. Essentially all components occurred at a frequency nωo. - mΩ, with m = 1, ..., n. But during its first week, the common superhump showed primary components at nωo - Ω, for n = 1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m = 1 consistently); a month later, the dominant power shifted to components with m = n -1. This may arise from a shift in the disk's spiral-arm pattern, likely to be the underlying cause of superhumps. The great majority of frequency components are redshifted from the harmonics of ωo, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 cycles day-1 suggests the possibility of a retrograde precession at a different rate, probably N = 0.13 ± 0.02 cycles day-1. The eclipses permit measuring the location and brightness of the mass-transfer hot spot. The disk must be very eccentric and nearly as large as the white dwarfs Roche lobe. The hot-spot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption.

LanguageEnglish (US)
Pages721-747
Number of pages27
JournalPublications of the Astronomical Society of the Pacific
Volume114
Issue number797
DOIs
StatePublished - 2002
Externally publishedYes

Fingerprint

precession
volcanic eruption
outburst
hot spot
mass transfer
volcanic eruptions
dwarf novae
brightness
accretion
time series
stars
orbitals
cycles
eccentrics
eclipses
daytime
accretion disks
lobes
light curve
echoes

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Patterson, J., Masi, G., Richmond, M. W., Martin, B., Beshore, E. C., Skillman, D. R., ... Walker, S. (2002). The 2001 superoutburst of WZ sagittae. Publications of the Astronomical Society of the Pacific, 114(797), 721-747. https://doi.org/10.1086/341696

The 2001 superoutburst of WZ sagittae. / Patterson, Joseph; Masi, Gianluca; Richmond, Michael W.; Martin, Brian; Beshore, Edward C; Skillman, David R.; Kemp, Jonathan; Vanmunster, Tonny; Rea, Robert; Allen, William; Davis, Stacey; Davis, Tracy; Henden, Arne A.; Starkey, Donn; Foote, Jerry; Oksanen, Arto; Cook, Lewis M.; Fried, Robert E.; Husar, Dieter; Novák, Rudolf; Campbell, Tut; Robertson, Jeff; Krajci, Thomas; Pavlenko, Elena; Mirabal, Nestor; Niarchos, Panos G.; Brettman, Orville; Walker, Stan.

In: Publications of the Astronomical Society of the Pacific, Vol. 114, No. 797, 2002, p. 721-747.

Research output: Contribution to journalArticle

Patterson, J, Masi, G, Richmond, MW, Martin, B, Beshore, EC, Skillman, DR, Kemp, J, Vanmunster, T, Rea, R, Allen, W, Davis, S, Davis, T, Henden, AA, Starkey, D, Foote, J, Oksanen, A, Cook, LM, Fried, RE, Husar, D, Novák, R, Campbell, T, Robertson, J, Krajci, T, Pavlenko, E, Mirabal, N, Niarchos, PG, Brettman, O & Walker, S 2002, 'The 2001 superoutburst of WZ sagittae' Publications of the Astronomical Society of the Pacific, vol. 114, no. 797, pp. 721-747. https://doi.org/10.1086/341696
Patterson J, Masi G, Richmond MW, Martin B, Beshore EC, Skillman DR et al. The 2001 superoutburst of WZ sagittae. Publications of the Astronomical Society of the Pacific. 2002;114(797):721-747. https://doi.org/10.1086/341696
Patterson, Joseph ; Masi, Gianluca ; Richmond, Michael W. ; Martin, Brian ; Beshore, Edward C ; Skillman, David R. ; Kemp, Jonathan ; Vanmunster, Tonny ; Rea, Robert ; Allen, William ; Davis, Stacey ; Davis, Tracy ; Henden, Arne A. ; Starkey, Donn ; Foote, Jerry ; Oksanen, Arto ; Cook, Lewis M. ; Fried, Robert E. ; Husar, Dieter ; Novák, Rudolf ; Campbell, Tut ; Robertson, Jeff ; Krajci, Thomas ; Pavlenko, Elena ; Mirabal, Nestor ; Niarchos, Panos G. ; Brettman, Orville ; Walker, Stan. / The 2001 superoutburst of WZ sagittae. In: Publications of the Astronomical Society of the Pacific. 2002 ; Vol. 114, No. 797. pp. 721-747.
@article{5a94c04de88c4a848710058bec18d7f8,
title = "The 2001 superoutburst of WZ sagittae",
abstract = "We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V = 15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ∼1 mag amplitude and 2 day recurrence time; these {"}echo outbursts{"} are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence. Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: A strong orbital signal dominated the first 12 days, followed by a powerful common superhump at 0.05721(5) day, 0.92(8){\%} longer than Porb. The latter endured for at least 90 days, although probably mutating into a {"}late{"} superhump with a slightly longer mean period [0.05736(5) day]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: The orbital frequency ωo and an unseen low frequency Ω, believed to represent the accretion disk's apsidal precession. Long time series reveal an intricate fine structure, with ∼20 incommensurate frequencies. Essentially all components occurred at a frequency nωo. - mΩ, with m = 1, ..., n. But during its first week, the common superhump showed primary components at nωo - Ω, for n = 1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m = 1 consistently); a month later, the dominant power shifted to components with m = n -1. This may arise from a shift in the disk's spiral-arm pattern, likely to be the underlying cause of superhumps. The great majority of frequency components are redshifted from the harmonics of ωo, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 cycles day-1 suggests the possibility of a retrograde precession at a different rate, probably N = 0.13 ± 0.02 cycles day-1. The eclipses permit measuring the location and brightness of the mass-transfer hot spot. The disk must be very eccentric and nearly as large as the white dwarfs Roche lobe. The hot-spot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption.",
author = "Joseph Patterson and Gianluca Masi and Richmond, {Michael W.} and Brian Martin and Beshore, {Edward C} and Skillman, {David R.} and Jonathan Kemp and Tonny Vanmunster and Robert Rea and William Allen and Stacey Davis and Tracy Davis and Henden, {Arne A.} and Donn Starkey and Jerry Foote and Arto Oksanen and Cook, {Lewis M.} and Fried, {Robert E.} and Dieter Husar and Rudolf Nov{\'a}k and Tut Campbell and Jeff Robertson and Thomas Krajci and Elena Pavlenko and Nestor Mirabal and Niarchos, {Panos G.} and Orville Brettman and Stan Walker",
year = "2002",
doi = "10.1086/341696",
language = "English (US)",
volume = "114",
pages = "721--747",
journal = "Publications of the Astronomical Society of the Pacific",
issn = "0004-6280",
publisher = "University of Chicago",
number = "797",

}

TY - JOUR

T1 - The 2001 superoutburst of WZ sagittae

AU - Patterson, Joseph

AU - Masi, Gianluca

AU - Richmond, Michael W.

AU - Martin, Brian

AU - Beshore, Edward C

AU - Skillman, David R.

AU - Kemp, Jonathan

AU - Vanmunster, Tonny

AU - Rea, Robert

AU - Allen, William

AU - Davis, Stacey

AU - Davis, Tracy

AU - Henden, Arne A.

AU - Starkey, Donn

AU - Foote, Jerry

AU - Oksanen, Arto

AU - Cook, Lewis M.

AU - Fried, Robert E.

AU - Husar, Dieter

AU - Novák, Rudolf

AU - Campbell, Tut

AU - Robertson, Jeff

AU - Krajci, Thomas

AU - Pavlenko, Elena

AU - Mirabal, Nestor

AU - Niarchos, Panos G.

AU - Brettman, Orville

AU - Walker, Stan

PY - 2002

Y1 - 2002

N2 - We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V = 15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ∼1 mag amplitude and 2 day recurrence time; these "echo outbursts" are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence. Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: A strong orbital signal dominated the first 12 days, followed by a powerful common superhump at 0.05721(5) day, 0.92(8)% longer than Porb. The latter endured for at least 90 days, although probably mutating into a "late" superhump with a slightly longer mean period [0.05736(5) day]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: The orbital frequency ωo and an unseen low frequency Ω, believed to represent the accretion disk's apsidal precession. Long time series reveal an intricate fine structure, with ∼20 incommensurate frequencies. Essentially all components occurred at a frequency nωo. - mΩ, with m = 1, ..., n. But during its first week, the common superhump showed primary components at nωo - Ω, for n = 1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m = 1 consistently); a month later, the dominant power shifted to components with m = n -1. This may arise from a shift in the disk's spiral-arm pattern, likely to be the underlying cause of superhumps. The great majority of frequency components are redshifted from the harmonics of ωo, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 cycles day-1 suggests the possibility of a retrograde precession at a different rate, probably N = 0.13 ± 0.02 cycles day-1. The eclipses permit measuring the location and brightness of the mass-transfer hot spot. The disk must be very eccentric and nearly as large as the white dwarfs Roche lobe. The hot-spot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption.

AB - We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V = 15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ∼1 mag amplitude and 2 day recurrence time; these "echo outbursts" are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence. Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: A strong orbital signal dominated the first 12 days, followed by a powerful common superhump at 0.05721(5) day, 0.92(8)% longer than Porb. The latter endured for at least 90 days, although probably mutating into a "late" superhump with a slightly longer mean period [0.05736(5) day]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: The orbital frequency ωo and an unseen low frequency Ω, believed to represent the accretion disk's apsidal precession. Long time series reveal an intricate fine structure, with ∼20 incommensurate frequencies. Essentially all components occurred at a frequency nωo. - mΩ, with m = 1, ..., n. But during its first week, the common superhump showed primary components at nωo - Ω, for n = 1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m = 1 consistently); a month later, the dominant power shifted to components with m = n -1. This may arise from a shift in the disk's spiral-arm pattern, likely to be the underlying cause of superhumps. The great majority of frequency components are redshifted from the harmonics of ωo, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 cycles day-1 suggests the possibility of a retrograde precession at a different rate, probably N = 0.13 ± 0.02 cycles day-1. The eclipses permit measuring the location and brightness of the mass-transfer hot spot. The disk must be very eccentric and nearly as large as the white dwarfs Roche lobe. The hot-spot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption.

UR - http://www.scopus.com/inward/record.url?scp=0000680206&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000680206&partnerID=8YFLogxK

U2 - 10.1086/341696

DO - 10.1086/341696

M3 - Article

VL - 114

SP - 721

EP - 747

JO - Publications of the Astronomical Society of the Pacific

T2 - Publications of the Astronomical Society of the Pacific

JF - Publications of the Astronomical Society of the Pacific

SN - 0004-6280

IS - 797

ER -