J/A+A/638/A108 4 p-mode pulsators arrival times (Mackebrandt+, 2020)
The EXOTIME project: signals in the O-C diagrams of the rapidly pulsating
subdwarfs DW Lyn, V1636 Ori, QQ Vir and V541 Hya.
Mackebrandt F., Schuh S., Silvotti R., Kim S.-L., Kilkenny D., Green E.M.,
Lutz R., Nagel T., Provencal J.L., Otani T., Oswalt T.D., Benatti S.,
Lanteri L., Bonanno A., Frasca A., Janulis R., Paparo M., Molnar L.,
Claudi R., Ostensen R.H.
<Astron. Astrophys. 638, A108 (2020)>
=2020A&A...638A.108M 2020A&A...638A.108M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, subdwarf ; Stars, B-type ; Asteroseismology
Keywords: stars: horizontal-branch - planets and satellites: detection -
subdwarfs - asteroseismology - techniques: photometric
Abstract:
We investigate variations in the arrival time of coherent stellar
pulsations due to the light travel time effect to test for the
presence of sub-stellar companions. Those companions are the key to
one possible formation scenario of apparently single subdwarf B stars.
We make use of an extensive set of ground-based observations of the
four large amplitude p-mode pulsators DW Lyn, V1636 Ori, QQ Vir and
V541 Hya. Observations of the TESS space telescope are available on
two of the targets. The timing method compares the phase of sinusoidal
fits to the full multi-epoch ligh curves with phases from the fit of a
number of subsets of the original time series.
TESS observations do not sample the pulsations well enough to be
useful due to the (currently) fixed 2 minute cadence. From the ground-
based observations, we infer evolutionary parameters from the arrival
times. The residual signals show many statistically significant
periodic signals, but no clear evidence for changes in arrival time
induced by sub-stellar companions. The signals can be explained partly
by mode beating effects. We derive upper limits on companion masses
set by the observational campaign.
Description:
Photometric measurements for subdwarf B stars DW Lyn, V1636 Ori, QQ
Vir and V541 Hya (Fig. 1), as well as phase- and amplitude-
measurements of DW Lyn and V1636 Ori (Fig. 8, 10, 12, 15), and
amplitude spectra in the appendix (Fig. A2, B1, B2, B3, B4).
Additional tables for each target include the partitioning of
observations into the epochs, separated by observatory (*obs.csv) and
the start-/end-times of each epoch (*epoch.csv).
Objects:
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RA (2000) DE Designation(s)
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07 07 09.796 +60 38 50.16 DW Lyn = HS0702+6043
04 47 18.632 +05 03 34.81 V1636 Ori = HS0444+0458
13 27 48.560 +09 54 51.05 QQ Vir = PG 1325+102
10 00 41.824 -11 51 34.59 V541 Hya = EC09582-1137
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
listlc.dat 46 452 List of light curve files
lc/* . 452 Individual light curves
dwla1.dat 74 38 Amplitude measurement for f1 of DW Lyn
dwla2.dat 74 38 Amplitude measurement for f2 of DW Lyn
qqva1.dat 74 62 Amplitude measurement for f1 of QQ Vir
qqva2.dat 74 62 Amplitude measurement for f2 of QQ Vir
qqva3.dat 74 62 Amplitude measurement for f3 of QQ Vir
v16a1.dat 74 29 Amplitude measurement for f1 of V1636 Ori
v16a2.dat 74 29 Amplitude measurement for f2 of V1636 Ori
v54a1.dat 74 18 Amplitude measurement for f1 of V541 Hya
v54a2.dat 74 18 Amplitude measurement for f2 of V541 Hya
dwlo1.dat 75 38 O-C measurement for f1 of DW Lyn
dwlo2.dat 75 38 O-C measurement for f2 of DW Lyn
dwlor1.dat 75 38 O-C measurement for f1 of DW Lyn
after subtracting quadratic trend
dwlor2.dat 75 38 O-C measurement for f2 of DW Lyn
after subtracting quadratic trend
qqvo1.dat 75 62 O-C measurement for f1 of QQ Vir
qqvo2.dat 75 62 O-C measurement for f2 of QQ Vir
qqvo3.dat 75 62 O-C measurement for f3 of QQ Vir
qqvor1.dat 75 62 O-C measurement for f1 of QQ Vi
after subtracting quadratic trend
qqvor2.dat 75 62 O-C measurement for f2 of QQ Vir
after subtracting quadratic trend
qqvor3.dat 75 62 O-C measurement for f3 of QQ Vir
after subtracting quadratic trend
v16o1.dat 75 29 O-C measurement for f1 of V1636 Ori
v16o2.dat 75 29 O-C measurement for f2 of V1636 Ori
v16or1.dat 75 29 O-C measurement for f1 of V1636 Ori
after subtracting quadratic trend
v16or2.dat 75 29 O-C measurement for f2 of V1636 Ori
after subtracting quadratic trend
v54o1.dat 75 18 O-C measurement for f1 of V541 Hya
v54o2.dat 75 18 O-C measurement for f2 of V541 Hya
v54or1.dat 75 18 O-C measurement for f1 of V541 Hya
after subtracting quadratic trend
v54or2.dat 75 18 O-C measurement for f2 of V541 Hya
after subtracting quadratic trend
dwlepoch.dat 47 42 DW Lyn epochs
qqvepoch.dat 47 62 QQ Vir epochs
v16epoch.dat 47 29 V1636 Ori epochs
v54epoch.dat 47 18 V541 Hya epochs
dwlobs.dat 51 189 Observing times of DW Lyn
qqvobs.dat 65 117 Observing times of QQ Vir
v16obs.dat 51 80 Observing times of V1636 Ori
v54obs.dat 51 65 Observing times of V541 Hya
dwlpw.dat 49 3823092 Amplitude spectrum of DW Lyn
dwlpwr.dat 49 3823092 Amplitude spectrum of DW Lyn
qqvpw.dat 49 7981192 Amplitude spectrum of QQ Vir
qqvpwr.dat 49 7981192 Amplitude spectrum of QQ Vir
v16pw.dat 49 5626036 Amplitude spectrum of V1636 Ori
v16pwr.dat 49 5626036 Amplitude spectrum of V1636 Ori
v54pw.dat 49 8777037 Amplitude spectrum of V541 Hya
v54pwr.dat 49 8777037 Amplitude spectrum of V541 Hya
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Byte-by-byte Description of file: listlc.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- FileName Name of the file with ligth curve
in subdirectory lc
14- 22 A9 --- Name Star name
24- 33 A10 "date" Obs.date Observation date
34- 36 A3 --- n_Obs.date Additional information on Obs.date
38- 46 A9 --- Inst Instrument
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Byte-by-byte Description of file: lc/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 E24.19 d MJD Modified Julian date
25- 50 E26.19 --- RFlux Relative flux
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Byte-by-byte Description of file (#): *a1.dat *a2.dat *a3.dat
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Bytes Format Units Label Explanations
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1- 24 E24.19 d MJD Time (mid time of the epoch)
26- 49 E24.19 10-2% Amp Amplitude
51- 74 E24.19 10-2% e_Amp Amplitude error
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Byte-by-byte Description of file: *epoch.dat
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Bytes Format Units Label Explanations
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1- 23 A23 "datime" Epoch1 Star time
25- 47 A23 "datime" Epoch2 End time
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Byte-by-byte Description of file (#): *o1.dat *o2.dat *o3.dat *or?.dat
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Bytes Format Units Label Explanations
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1- 24 E24.19 d MJD Time (mid time of the epoch)
26- 50 E25.19 s O-C O-C of arrival time
52- 75 E24.19 s e_O-C O-C of arrival time error
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Byte-by-byte Description of file: dwlobs.dat qqvobs.dat v16obs.dat v54obs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Epoch Epoch number
4- 10 A7 --- Obs Observatory
12- 21 A10 "date" Obs.date Observation date
23- 33 A11 "h:m:s" Start UTC start
35- 45 A11 "h:m:s" End UTC end
47- 51 F5.2 h Obs.time ? Time of observation, in decimal hours
53- 67 A15 --- Note Note
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Byte-by-byte Description of file: *pw.dat *pwr.dat
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Bytes Format Units Label Explanations
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1- 24 E24.19 d-1 Freq Frequency
26- 49 E24.19 10-2% Amp Amplitude
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Acknowledgements:
Felix Mackebrandt mackebrandt(at)mps.mpg.de
(End) Patricia Vannier [CDS] 25-Mar-2020