J/MNRAS/509/2885 Computed PCRs in LMC Cepheids (Rodriguez-Segovia+, 2022)
Period-change rates in Large Magellanic Cloud Cepheids revisited.
Rodriguez-Segovia N., Hajdu G., Catelan M., Espinoza-Arancibia F.,
Boggiano G., Cenzano C., Garces E.H., Joachimi K., Munoz-Lopez C.,
Ordenes-Huanca C., Orquera-Rojas C., Torres P., Valenzuela-Navarro A.
<Mon. Not. R. Astron. Soc. 509, 2885-2895>
=2022MNRAS.509.2885R 2022MNRAS.509.2885R (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, variable ; Optical ;
Photometry ; Positional data
Keywords: methods: data analysis - stars: evolution -
stars: variables: Cepheids - Magellanic Clouds
Abstract:
The period-change rate (PCR) of pulsating variable stars is a useful
probe of changes in their interior structure, and thus of their
evolutionary stages. So far, the PCRs of classical Cepheids in the
Large Magellanic Cloud (LMC) have been explored in a limited sample of
the total population of these variables. Here, we use a template-based
method to build observed-minus-computed (O - C) period diagrams, from
which we can derive PCRs for these stars by taking advantage of the
long time baseline afforded by the Digital Access to a Sky Century
@Harvard light curves, combined with additional data from the Optical
Gravitational Lensing Experiment, the MAssive Compact Halo Object
project, Gaia's Data Release 2, and in some cases the All-Sky
Automated Survey. From an initial sample of 2315 sources, our method
provides an unprecedented sample of 1303 LMC classical Cepheids with
accurate PCRs, the largest for any single galaxy, including the Milky
Way. The derived PCRs are largely compatible with theoretically
expected values, as computed by our team using the Modules for
Experiments in Stellar Astrophysics code, as well as with similar
previous computations available in the literature. Additionally, five
long-period (P > 50 d) sources display a cyclic behaviour in their O - C
diagrams, which is clearly incompatible with evolutionary changes.
Finally, on the basis of their large positive PCR values, two
first-crossing Cepheid candidates are identified.
Description:
Our goal in this paper is to calculate PCRs for LMC classical Cepheids
pulsating in the fundamental mode, using both DASCH data and more
recent data sets from the literature. This also allows us to revisit
previously published PCR values calculated for smaller Cepheid samples
(Pietrukowicz 2001AcA....51..247P 2001AcA....51..247P; Karczmarek et al.
2011AcA....61..303K 2011AcA....61..303K), and to compare the measured values with those
computed on the basis of state-of-the-art theoretical Cepheid models
(e.g. Turner et al. 2006PASP..118..410T 2006PASP..118..410T).
As explained in the section 3 Method, by using the OGLE Collection of
Variable Stars (OCVS; Soszynski et al. 2015AcA....65..297S 2015AcA....65..297S, Cat.
J/AcA/65/297), 2315 Cepheids pulsating in their fundamental mode were
selected and their periods retrieved. After criteria selections and
cross-matches with related catalogue (i.e section 3 Method), we have
successfully measured PCRs for 1303 variables out of our initial
sample of 2315. These values are listed in the table2.dat.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 67 1303 Computed period-change rates (PCRs) for our
sample of 1303 variables
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See also:
J/AcA/65/297 : OGLE4 LMC and SMC Cepheids (Soszynski+, 2015)
J/AcA/58/163 : VI light curves of LMC classical Cepheids (Soszynski+, 2008)
II/264 : ASAS Variable Stars in Southern hemisphere
(Pojmanski+, 2002-2005)
J/AcA/62/247 : LMC photometric maps from OGLE-III shallow survey
(Ulaczyk+, 2012)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I04 --- Star OGLE-IV identifier following the format
OGLE-LMC-CEP-NNNN (Source) (1)
6- 14 F9.6 deg RAdeg Right Ascension provided by OGLE (J2000) (RA)
16- 25 F10.6 deg DEdeg Declination provided by OGLE (J2000) (Dec)
27- 36 F10.7 d P POGLE equal to OGLE-IV periods used for
creating the light curve template (POGLE)
38- 44 F7.1 d/Myr dP/dt Computed period-change rate PCR rounded
to one decimal (PCR)
46- 49 F4.1 d/Myr e_dP/dt Uncertainty adopted as the mean and
standard deviation of the marginalized
posterior distribution rounded
to one decimal (err_PCR)
51- 60 A10 --- Data Data available for the source code (Data) (2)
62- 63 I2 --- NFs Number of terms in Fourier series used for
building the light curve (Fourier) (3)
65- 67 A3 --- Template Data used to build the light curve template
(Template) (2)
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Note (1): Star's name ID from OGLE IV LMC and SMC Cepheids (Soszynski et al.
2015AcA....65..297S 2015AcA....65..297S, Cat. J/AcA/65/297).
Note (2): The source codes for data availability are as follows:
1A = DASCH, Photographic band, date of 1890-1990 years, Tang et al.
2013PASP..125..857T 2013PASP..125..857T
1B = DASCH, Photographic band, date of 1890-1990 years, Tang et al.
2013PASP..125..857T 2013PASP..125..857T
2 = MACHO , MACHO b band, date of 1993-2000 years, Alcock et al.
2000ApJ...542..281A 2000ApJ...542..281A
3 = OGLE-III, Johnson V band, date of 1997-2008 years,
Soszynski et al. 2008AcA....58..163S 2008AcA....58..163S, Cat. J/AcA/58/163
4 = ASAS-3, Johnson V band, date of 2001-2010 years, Pojmanski G.
2002AcA....52..397P 2002AcA....52..397P, Cat. II/264
5 = OGLE Shallow, Johnson V band, date of 2005-2009 years,
Ulaczyk et al. 2012AcA....62..247U 2012AcA....62..247U, Cat. J/AcA/62/247
6 = OGLE-IV, Johnson V band, date of 2010-2016 years, Udalski et al.
2015AcA....65....1U 2015AcA....65....1U
7 = Gaia DR2, Gaia BP band, date of 2015-2016 years, Gaia
Collaboration 2018A&A...616A...1G 2018A&A...616A...1G, Cat. I/345
Note (3): As exlpained in the 3.4 The adopted O - C method, a light-curve
template is constructed through a truncated Fourier series (TFS)
as shown in the equation 1.
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 23-Sep-2024