J/A+A/695/A210 RVs of binaries black hole/Sun-like stars (Green+, 2025)
An upper limit on the frequency of short-period black hole companions to
Sun-like stars.
Green M.J., Ziv Y., Rix H.-W., Maoz D., Hamoudy I., Mazeh T., Faigler S.,
Lam M.C., El-Badry K., Hume G., Munday J., Yarker P.
<Astron. Astrophys. 695, A210 (2025)>
=2025A&A...695A.210G 2025A&A...695A.210G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, G-type ; Black holes ;
Binaries, orbits ; Radial velocities
Keywords: binaries: close - stars: black holes - stars: solar-type
Abstract:
Stellar-mass black holes descend from high-mass stars, most of which
had stellar binary companions. However, the number of those binary
systems that survive the binary evolution and black hole formation is
uncertain by multiple orders of magnitude. The survival rate is
particularly uncertain for massive stars with low-mass companions,
which are thought to be the progenitors of most black hole X-ray
binaries. We present a search for close black hole companions
(orbital period ≲3 days, equivalent to separation ≲20R☉) to
AFGK-type stars in TESS, i.e. the non-accreting counterparts to and
progenitors of low-mass X-ray binaries. Such black holes can be
detected by the tidally induced ellipsoidal deformation of the visible
star, and the ensuing photometric light-curve variations. From an
initial sample of 4.7x106 TESS stars, we have selected 457
candidates for such variations. However, spectroscopic followup of 251
of them shows that none are consistent with a close black hole
companion. On the basis of this non-detection, we determine (2σ
confidence) that fewer than one in 105 Solar-type stars in the Solar
neighbourhood host a short-period black hole companion. This upper
limit is in tension with a number of "optimistic" population models in
the literature that predict short-period black hole companions around
one in ∼104-5 stars. Our limits are still consistent with other
models that predict only a few in ∼107-8.
Description:
We observed 60 of the targets selected in the previous section
on the New Technology Telescope (NTT) and the Isaac Newton Telescope
(INT). Radial velocities for further targets were obtained from survey
data.
A full list of all targets followed up or retrieved is given in Table 3.
Table 4 gives individual RV epochs obtained from our INT and NTT data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 110 323 Results (K-amplitude and implied companion mass
limit) for all candidate binaries containing
black hole followed up in this paper
table4.dat 48 478 Radial velocities measured from individual
exposures on the targets listed in Table 3
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See also:
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC ID number of the target in TESS input catalog
11- 18 A8 --- Tel Telescope was used for the observations (1)
20- 21 I2 --- Nepochs Number of epochs of observation
23- 31 F9.7 d Porb ?=- Orbital period
33- 42 F10.8 d e_Porb ?=- Orbital period uncertainty
44- 52 F9.5 km/s K Orbital velocity semi-amplitude
54- 62 F9.6 km/s e_K ?=- Orbital velocity semi-amplitude uncertainty
64- 73 F10.8 Msun MinM2 ?=- Spectroscopic lower limit on companion mass
75- 85 F11.9 Msun e_MinM2 ?=- Spectroscopic lower limit on companion mass
uncertainty
87- 96 F10.8 --- Minq ?=- Spectroscopic lower limit on mass ratio
98-108 F11.9 --- e_Minq ?=- Spectroscopic lower limit on mass ratio
uncertainty
110 I1 --- SB2? [0/1] True if the target spectra showed two
spectral components
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Note (1): Telescopes are INT, NTT, Gaia RVs, Gaia SB1 or Gaia SB2.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC ID number of the target in the TESS input catalog
11- 13 A3 --- Tel [INT NTT] Telescope used for the observations
15- 30 F16.8 d BJD Barycentric Julian Date of the mid-exposure time
(in Barycentric Dynamic Time)
32- 40 F9.4 km/s RV Measured radial velocity
42- 48 F7.5 km/s e_RV Measured radial velocity uncertainty
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Acknowledgements:
Matthew Green, mjgreenastro(at)gmail.com
(End) Patricia Vannier [CDS] 28-Feb-2025