The primordial binary population. I. A near-infrared adaptive optics search for close visual companions to A star members of Scorpius OB2

By M. B. N. Kouwenhoven, Anthony G. A. Brown, H. Zinnecker, L. Kaper, S. P. Portegies Zwart. 2004

152 citations recorded by the source corpus.

We present the results of a near-infrared adaptive optics survey with the aim to detect close companions to Hipparcos members in the three subgroups of the nearby OB association Sco OB2: Upper Scorpius (US), Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC). We have targeted 199 A-type and late B-type stars in the K S band, and a subset also in the J and H band. We find 151 stellar components other than the target stars. A brightness criterion is used to separate these components into 77 background stars and 74 candidate physical companion stars. Out of these 74 candidate companions, 41 have not been reported before (14 in US; 13 in UCL; 14 in LCC). The angular separation between primaries and observed companion stars ranges from 0.22 to 12.4. At the mean distance of Sco OB2 (130 pc) this corresponds to a projected separation of 28.6 AU to 1612 AU. Absolute magnitudes are derived for all primaries and observed companions using the parallax and interstellar extinction for each star individually. For each object we derive the mass from K S , assuming an age of 5 Myr for the US subgroup, and 20 Myr for the UCL and LCC subgroups. Companion star masses range from 0.10 M ○. to 3.0 M ○. . The mass ratio distribution follows f(q) = q -Γ with r = 0.33, which excludes random pairing. No close (ρ ≤ 3.75) companion stars or background stars are found in the magnitude range 12 mag 14 mag are observed. If these components are very low-mass companion stars, a gap in the companion mass distribution might be present. The small number of close low-mass companion stars could support the embryo-ejection formation scenario for brown dwarfs. Our findings are compared with and complementary to visual, spectroscopic, and astrometric data on binarity in Sco OB2. We find an overall companion star fraction of 0.52 in this association. This is a lower limit since the data from the observations and from literature are hampered by observational biases and selection effects. This paper is the first step toward our goal to derive the primordial binary population in Sco OB2.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/416f559cf4912a1c34ff595fb8baade16536aa5a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics Observations (2007, methodology): “Ser. Conf., 8, 41 Shatsky, N., & Tokovinin, A. 2002, A&A, 382, 92 Sher, D. 1965, MNRAS, 129, 237 Siess, L., Dufour, E., & Forestini, M. 2000, A&A, 358, 593 Sirianni, M., Nota, A., De Marchi, G., Leitherer, C., & Clampin, M. 2000, ApJ, 533, 203 Slesnick, C. L., Hillenbrand, L. A., & Massey, P. 2002, ”
Long-baseline interferometric multiplicity survey of the Sco-Cen OB association (2013, methodology): “A survey of 199 A and late B-type stars in Sco OB2 was done by Kouwenhoven et al. (2005) using the ESO 3.6 m telescope at La Silla, Chile with the ADONIS/SHARPII+ imaging instrument with the aim of detecting new visual binaries.”
The VAST Survey - III. The multiplicity of A-type stars within 75 pc (2013, methodology): “The measured CSF for A-type primaries is similar to that of early-type stars within the young Sco OB2 stellar association (Kouwenhoven et al. 2005), when limited to a common separation and mass ratio range (Fig.”
A spectroscopic survey on the multiplicity of high-mass stars (2012, background): “…rate for the late B-types is slightly higher in Sco OB2; the latter difference might be due to the different observing techniques, because without the adaptive optics data of Kouwenhoven et al. (2005) the c© 2011 RAS, MNRAS 000, 1–6 multiplicity rate would drop by about 10% for the late Btypes.”
DISCOVERY OF A PROBABLE 4–5 JUPITER-MASS EXOPLANET TO HD 95086 BY DIRECT IMAGING (2013, background): “Finally, Kouwenhoven et al. (2005) observed HD95086 with adaptive-optics and identified a background star with a separation of 4.87 ′′ and position angle of 316 deg to the star (based on its K magnitude).”
The formation of very wide binaries during the star cluster dissolution phase (2010, background): “…following three useful quantities describing themultiplicity of a stellar population can be used: B = (B+ T + . . . )/(S + B+ T + . . . ) (2) N = (2B+ 3T + . . . )/(S + 2B+ 3T + . . . ) (3) C = (B+ 2T + . . . )/(S + B+ T + . . . ) (4) (see, e.g., Reipurth & Zinnecker 1993; Kouwenhoven et al. 2005).”
Dawes Review 6: The Impact of Companions on Stellar Evolution (2016, background): “Amongst the entire group of F2 to B5 type stars, the binary frequency is greater than about 50% , as determined from the Sco-Cen OB association (Kouwenhoven et al., 2005; Fuhrmann & Chini, 2012, 2015).”
Shadows and spirals in the protoplanetary disk HD 100453 (2016, background): “Of particular interest for this paper is HD 100453 A, hereafter referred to as simply HD 100453, a Herbig A9Ve star located in the Lower Centaurus Association (Kouwenhoven et al. 2005), at ∼114+11−4 pc (Perryman et al. 1997), with an early-M star companion (Chen et al. 2006).”
Massive runaway and walkaway stars (2018, methodology): “For each primary star of mass MZAMS1 , we select Nq secondaries with mass MZAMS2 = qM ZAMS 1 , taken at regular intervals in mass ratio q between 0.1 and 1 assuming a flat distribution (slope κ = 0, e.g., Kouwenhoven et al. 2005).”
THE PALOMAR/KECK ADAPTIVE OPTICS SURVEY OF YOUNG SOLAR ANALOGS: EVIDENCE FOR A UNIVERSAL COMPANION MASS FUNCTION (2008, background): “Preship testing., California Institute of Technology, http://www2.keck.hawaii.edu/inst/nirc2/preship testing.pdf Tinney, C. G., Mould, J. R., & Reid, I. N. 1993, AJ, 105, 1045 Tokovinin, A., Thomas, S., Sterzik, M., & Udry, S. 2006, A&A, 450, 681 Tokovinin, A. A., Chalabaev, A., Shatsky, N. I., & Be”
New constraints on the multiplicity of massive young stars in Upper Scorpius (2015, methodology): “Kouwenhoven et al. (2005, 2007) have published an extended study of the primordial binary population in Scorpius Centaurus.”