J/A+A/630/A80 EREBOS project. I. (Schaffenroth+, 2019)
The EREBOS project: Investigating the effect of substellar and low-mass stellar
companions on late stellar evolution.
Survey, target selection, and atmospheric parameters.
Schaffenroth V., Barlow B.N., Geier S., Vuckovic M., Kilkenny D., Wolz M.,
Kupfer T., Heber U., Drechsel H., Kimeswenger S., Marsh T., Wolf M.,
Pelisoli I., Freudenthal J., Dreizler S., Kreuzer S., Ziegerer E.
<Astron. Astrophys., 630, A80 (2019)>
=2019A&A...630A..80S 2019A&A...630A..80S (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Binaries, eclipsing ; Binaries, spectroscopic ;
Parallaxes, trigonometric ; Proper motions ; Photometry
Keywords: binaries: eclipsing - brown dwarfs - binaries: spectroscopic -
binaries: close - subdwarfs - surveys
Abstract:
Eclipsing post-common-envelope binaries are highly important for
resolving the poorly understood, very short-lived common-envelope
phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare
helium-burning cores of red giants that have lost almost all of their
hydrogen envelope. This mass loss is often triggered by
common-envelope interactions with close stellar or even substellar
companions. Cool companions to hot subdwarf stars such as late-type
stars and brown dwarfs are detectable from characteristic light-curve
variations - reflection effects and often eclipses. In the recently
published catalog of eclipsing binaries in the Galactic Bulge and in
the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey, we
discovered 125 new eclipsing systems showing a reflection effect seen
by visual inspection of the light curves and using a machine-learning
algorithm, in addition to the 36 systems previously discovered by the
Optical Gravitational Lesing Experiment (OGLE) team. The Eclipsing
Reflection Effect Binaries from Optical Surveys (EREBOS) project aims
at analyzing all newly discovered eclipsing binaries of the HW Vir
type (hot subdwarf + close, cool companion) based on a spectroscopic
and photometric follow up to derive the mass distribution of the
companions, constrain the fraction of substellar companions, and
determine the minimum mass needed to strip off the red-giant envelope.
To constrain the nature of the primary we derived the absolute
magnitude and the reduced proper motion of all our targets with the
help of the parallaxes and proper motions measured by the Gaia mission
and compared those to the Gaia white-dwarf candidate catalog. It was
possible to derive the nature of a subset of our targets, for which
observed spectra are available, by measuring the atmospheric parameter
of the primary, confirming that less than 10% of our systems are not
sdO/Bs with cool companions but are white dwarfs or central stars of
planetary nebula. This large sample of eclipsing hot subdwarfs with
cool companions allowed us to derive a significant period distribution
for hot subdwarfs with cool companions for the first time showing that
the period distribution is much broader than previously thought and is
ideally suited to finding the lowest-mass companions to hot subdwarf
stars. The comparison with related binary populations shows that the
period distribution of HW Vir systems is very similar to WD+dM systems
and central stars of planetary nebula with cool companions. In the
future, several new photometric surveys will be carried out, which
will further increase the sample of this project, providing the
potential to test many aspects of common-envelope theory and binary
evolution.
Description:
The EREBOS (Eclipsing Reflection Effect Binaries from Optical Surveys)
project aims to study a large sample of homogeneously selected HW Vir
systems (eclipsing binaries with cool stellar or substellar
companions), and in particular their orbital, atmospheric, and
fundamental parameters.
Two different photometric surveys are used to search such systems:
OGLE (a long-term, large-scale photometric sky survey focused on
variability, see Udalski et al., 2015AcA....65....1U 2015AcA....65....1U) and
ATLAS (a high-cadence all-sky survey system designed to find dangerous
near-Earth asteroids, see Tonry et al., 2018PASP..130f4505T 2018PASP..130f4505T).
The number of known HW Vir systems results increased by a factor of
almost ten.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 189 169 Orbital parameters, Gaia and OGLE magnitudes,
and coordinates of the HW Vir candidates and
published HW Vir systems
tablea2.dat 175 7 Orbital parameters, OGLE and Gaia magnitudes,
and coordinates of the white dwarf candidates
tablea3.dat 180 5 Orbital parameters, OGLE and Gaia magnitudes,
and coordinates of central stars of planetary
nebula from Miszalski et al.
(2009A&A...496..813M 2009A&A...496..813M, Cat. J/A+A/496/813)
tablea4.dat 120 134 Gaia parallaxes, proper motions and calculated
reduced proper motions, distances, absolute G
magnitudes, and reddening of the HW Vir
candidates and published HW Vir systems
tablea5.dat 120 7 Gaia parallaxes, proper motions and calculated
reduced proper motions, distances, absolute G
magnitudes and reddening of the white dwarf
candidates
tablea6.dat 118 3 Gaia parallaxes, proper motions and calculated
reduced proper motions, distances, absolute G
magnitudes and reddening of central stars of
planetary nebula from Miszalski et al.
(2009A&A...496..813M 2009A&A...496..813M, Cat. J/A+A/496/813)
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2
(Bailer-Jones+, 2018)
J/A+A/496/813 : Binary PNe towards the Galactic bulge (Miszalski+, 2009)
J/AcA/63/115 : OGLE-III Galactic disk eclipsing binaries (Pietrukowicz+, 2013)
J/AcA/65/39 : OGLE Galactic Bulge ultra-short-period binaries
(Soszynski+, 2015)
J/A+A/621/A38 : Gaia catalogue of hot subluminous stars (Geier+, 2019)
Byte-by-byte Description of file: tablea[123].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Sample [1/6] Sample (G1)
3- 21 A19 --- Target Target name
23- 24 I2 h RAOh ? OGLE right ascension (J2000)
26- 27 I2 min RAOm ? OGLE right ascension (J2000)
29- 33 F5.2 s RAOs ? OGLE right ascension (J2000)
35 A1 --- DEO- OGLE declination sign (J2000)
36- 37 I2 deg DEOd ? OGLE declination sign (J2000)
39- 40 I2 arcmin DEOm ? OGLE declination sign (J2000)
42- 45 F4.1 arcsec DEOs ? OGLE declination sign (J2000)
47- 48 I2 h RAh ? Gaia right ascension (ICRS) at Ep=2015.5
50- 51 I2 min RAm ? Gaia right ascension (ICRS) at Ep=2015.5
53- 59 F7.4 s RAs ? Gaia right ascension (ICRS) at Ep=2015.5
61 A1 --- DE- Gaia declination sign (ICRS) at Ep=2015.5
62- 63 I2 deg DEd ? Gaia declination sign (ICRS) at Ep=2015.5
65- 66 I2 arcmin DEm ? Gaia declination sign (ICRS) at Ep=2015.5
68- 73 F6.3 arcsec DEs ? Gaia declination sign (ICRS) at Ep=2015.5
75- 80 F6.3 mag Imag ? OGLE I magnitude
82- 87 F6.3 mag Vmag ? OGLE V magnitude
89- 95 F7.4 mag Gmag ? Gaia G magnitude
97-102 F6.4 mag e_Gmag ? rms uncertainty on Gmag
104-110 F7.4 mag GBPmag ? Gaia GBP magnitude
112-117 F6.4 mag e_GBPmag ? rms uncertainty on GBPmag
119-125 F7.4 mag GRPmag ? Gaia GRP magnitude
127-132 F6.4 mag e_GRPmag ? rms uncertainty on GRPmag
134-140 F7.4 mag GBP-GRP ? GPB-GRP colour index
142-151 F10.8 d Per ? Period
153-162 F10.5 d T0 ? Epoch (HJD-2400000)
164-189 A26 --- OName Other name
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Byte-by-byte Description of file: tablea[456].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1 I1 --- Sample [1/6] Sample (G1)
3- 21 A19 --- Target Target name
23- 29 F7.4 mas Plx Parallax
31- 36 F6.4 mas e_Plx rms uncertainty on Parallax
38- 44 F7.3 mas/yr pmRA Proper motion along RA, pmRA*cosDE
46- 50 F5.3 mas/yr e_pmRA rms uncertainty on pmRA
52- 58 F7.3 mas/yr pmDE Proper motion along DE
60- 64 F5.3 mas/yr e_pmDE rms uncertainty on pmDE
66- 70 F5.2 mag GMAG ? Absolute Gaia G magnitude
72- 76 F5.2 mag e_GMAG ? rms uncertainty on GMAG
79- 84 F6.3 --- HG Reduced proper motion
86- 89 F4.2 --- e_HG rms uncertainty on HG
91- 98 F8.3 kpc Dist ? Distance
100-107 F8.3 kpc e_Dist ? rms uncertainty on Dist
110-114 F5.3 mag AG ? Absorption in G band
116-120 F5.3 mag E(B-V) ? Reddening
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Global Notes:
Note (G1): Samples as follows:
1 = Discovered by Soszynski et al. (2015AcA....65...39S 2015AcA....65...39S, Cat. J/AcA/65/39)
2 = Discovered by visual inspection.
3 = Discovered by machine-learning.
4 = Discovered by Pietrukowicz et al. (2013AcA....63..115P 2013AcA....63..115P, Cat. J/AcA/63/115)
5 = Discovered by cross-match of the sdB candidate catalog (Geier et al.,
2019A&A...621A..38G 2019A&A...621A..38G, Cat. J/A+A/621/A38) with the ATLAS survey.
6 = Published HW Vir systems
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Dec-2019