J/AJ/169/196 Eclipses in gamma Persei light curve from SMEI (Adam+, 2025)
Filling the gap: The missing eclipses of gamma Persei from 2005 and from 2006
Adam R.Z., Molnar L.
<Astron. J., 169, 196 (2025)>
=2025AJ....169..196A 2025AJ....169..196A
ADC_Keywords: Binaries, eclipsing; Photometry; Optical;
Stars, double and multiple;
Keywords: Eclipsing binary stars ; Computational methods ; Photometry
Abstract:
γ Persei is a long-period (P∼14.6yr) eclipsing binary system.
Its period makes it a difficult target to fully understand: so far,
only two primary eclipses are known in the literature, from 1990 and
from 2019, whereas the 2005 one was missed due to its closeness to the
Sun at the time. We aimed to fill in this gap by processing the
quasi-continuous photometry collected by the Solar Mass Ejection
Imager (SMEI) between 2003 and 2011, which was ideally positioned to
observe such a bright targets. In order to do that, we first
determined a color-dependent conversion formula from the SMEI
measurements into Gaia G magnitudes. We applied various corrections to
the photometry and provide the longest continuous light curve of
γ Persei. We successfully detected the 2005 primary eclipse of
the system, with the yearly observations ending during the egress of
the companion. We predicted the position of a possible secondary
eclipse by forward modeling the binary system with PHOEBE, and
successfully recovered the secondary eclipse in the 2006 SMEI
observations. The existence of the secondary eclipse puts strong
constraints on the orbital configuration, which will be an important
constraint for future studies of the system.
Description:
The Solar Mass Ejection Imager (SMEI) was a heliophysics instrument
funded by NASA, the US Air Force, and the University of Birmingham.
SMEI was launched on the US Department of Defense Space Test
Program's Coriolis satellite in 2003 January and was deactivated in
2011 September.
Here, we present the missing primary eclipse from 2005 and the first
ever recorded secondary eclipse from 2006 as observed by the SMEI
instrument. The observed passband was between 450 and 950nm, where the
quantum efficiency of the CCD was at least 10%, and the exposure
cadence was 4s.
First, we determined a conversion between the SMEI intensities and the
Gaia G-band magnitudes. Then we processed the observations, and
corrected the light curves for a number of instrumental systematics.
Finally, we transformed the corrected intensities into the Gaia G band.
Objects:
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RA (2000) DE Designation(s) (Period)
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03 04 47.82 +53 30 23.2 gamma Persei = * 23 Per (Per=14.6yr=5329.08d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 39 36628 Processed SMEI light curve of gamma Persei
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See also:
B/sb9 : SB9: 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix+ 2004-2014)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/456/651 : psi Cen light curves (Bruntt+, 2006)
J/ApJ/683/433 : Polaris monitoring (Bruntt+, 2008)
J/ApJ/902/63 : SMEI photometry of Betelgeuse (Joyce+, 2020)
J/MNRAS/492/2709 : Double-lined spectroscopic binaries cat. (Piccotti+, 2020)
J/A+A/663/A4 : Mean PASTEL atmospheric parameters (Soubiran+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD [2673.4/5833.3] Barycentric Julian Date in
TDB-2450000
13- 20 F8.6 mag Gmag [2.38/3.05]? Apparent Gaia G-band magnitude
22- 29 F8.6 mag e_Gmag [0.07/0.11]? Uncertainty in Gmag
31- 39 F9.6 mag SMEImag [-6.45/-5.31] Raw SMEI observed magnitude
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 12-Jan-2026