J/A+A/694/A172 Newborn Be star system (Rivinius+, 2025)
Newborn Be star systems observed shortly after mass transfer.
Rivinius T., Klement R., Chojnowski S.D., Baade D., Abdul-Masih M.,
Przybilla N., Guarro Flo J., Heathcote B., Hadrava P., Gies D., Shepard K.,
Buil C., Garde O., Thizy O., Monnier J.D., Anugu N., Lanthermann C.,
Schaefer G., Davies C., Kraus S., Ennis J., Setterholm B.R., Gardner T.,
Ibrahim N., Chhabra S., Gutierrez M., Codron I., Mortimer D.
<Astron. Astrophys. 694, A172 (2025)>
=2025A&A...694A.172R 2025A&A...694A.172R (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Binaries, orbits ; Radial velocities ;
Interferometry ; Stars, Be
Keywords: binaries: spectroscopic - circumstellar matter -
stars: emission-line, Be - stars: massive
Abstract:
Many classical Be stars acquire their very rapid rotation by mass and
angular-momentum transfer in massive binaries. Short-lived
intermediate-phase objects have only been discovered recently. Data
archives and the literature have been searched for additional
candidates exhibiting this patterns. Thirteen candidates were
identified at various confidence levels. Adding to the two known
systems identified as classical Be star+pre-subdwarf binaries (LB-1
and HR 6819), two more (V742 Cas, HD 44637) could be confirmed with
interferometry, with V742 Cas setting a new record for the smallest
visually observed angular semi-major axis, at a=0.663mas. Two further
ones (V447 Sct, V1362 Cyg) are not resolved interferometrically, but
other evidence puts them at the same confidence level as LB-1.
V2174 Cyg is a candidate with very high confidence, but was not
observed interferometrically. The remaining ones are either candidates
with varying levels of confidence. Of a mostly magnitude complete
sample of 328 Be stars, 0.5-1% are found to have recently completed
the mass overflow that led to their formation. Another 5% are systems
with compact subdwarf companions, i.e., further evolved after a
previous overflow, and possibly two more percent harbor white dwarfs.
All these systems are of early B-subtypes, however, and if the
original sample is restricted to early subtypes (136 objects), these
percentages increase by a factor of about 2.5, while dropping to zero
for the mid and late subtypes (together 204 objects). This strongly
suggests that early- vs. mid- and late-type Be stars have differently
weighted channels to acquire their rapid rotation, namely binary
interaction vs. evolutionary spin-up.
Description:
Radial velocity measurements for four binary systems (V447 Sct,
V1362 Cyg, V742 Cas, HD 44637) and interferometric data log, list of
calibrator stars, and relative astrometric positions and flux ratios
of the V742 Cas binary system.
Objects:
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RA (2000) DE Designation(s)
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18 44 33.34 -07 06 38.1 V447 Sct = HIP 91946
20 03 41.59 +36 25 32.1 V1362 Cyg = HIP 98778
00 11 37.14 +58 12 42.5 V742 Cas = HIP 940
06 23 24.68 +15 06 06.4 HD 44637 = HIP 30389
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 40 12 Radial velocities for V447 Sct
tablea2.dat 46 32 Radial velocities for V1362 Cyg
tablea3.dat 46 31 Radial velocities for V742 Cas
tablea4.dat 46 27 Radial velocities for HD 44637
tableb1.dat 79 24 log of interferometric observations
tableb2.dat 45 10 List of calibrators
tableb3.dat 104 12 Relative astrometry and fluxes for V742Cas
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Byte-by-byte Description of file: tablea?.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d MJD Modified Julian date
24- 30 F7.2 km/s RV Radial velocity
36- 46 A11 --- Source Origin of spectrum
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Target Object Name
13- 24 A12 --- Inst Interferometer used
29- 34 A6 --- Band/Res Observing band/Resolution
39- 47 F9.3 d MJD Modified Julian date
52- 62 A11 "date" Date Civil date
67- 79 A13 --- Calibrator Object Name
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Byte-by-byte Description of file: tableb2.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Calibrator Object Name
18- 22 F5.3 mas UDdiamH Uniform disk diameter, H band
25- 29 F5.3 mas e_UDdiamH Uniform disk diameter error, H band
34- 38 F5.3 mas UDdiamK Uniform disk diameter, K band
41- 45 F5.3 mas e_UDdiamK Uniform disk diameter error, K band
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Byte-by-byte Description of file: tableb3.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian date
14- 19 F6.4 mas Sep Separation
24- 30 F7.3 deg PA Position angle
37- 43 F7.4 mas oRA Offset in RA
47- 53 F7.4 mas oDE Offset in DEC
58- 63 F6.4 mas e-amaj Error ellipse major axis length
68- 73 F6.4 mas e-bmin Error ellipse minor axis length
78- 83 F6.2 deg e-PA Error ellipse position angle
88- 91 F4.1 % fpri Primary flux percentage
93- 95 F3.1 % e_fpri Primary flux percentage, positive error
97- 99 F3.1 % E_fpri Primary flux percentage, negative error
104 A1 --- Band Observing band
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Acknowledgements:
T. Rivinius, triviniu(at)eso.org
(End) Patricia Vannier [CDS] 24-Jan-2025