All Tables

Table 1: Observed target stars: B- and A-type members of Per OB2 identified by Z99, supplemented with a number of early-type stars identified as members in pre-Hipparcos investigations (e.g., B52). The stars were observed in order of decreasing brightness, resulting in spectra for 29 distinct targets (62 exposures). Columns: (1) HD number (Hipparcos Catalogue field H71); (2) Hipparcos identifier (H1); (3) name; (4) V magnitude (H5); (5) spectral type and luminosity class; (6) number of spectra obtained (N; subtractions refer to suspect exposures related to detector instability); (7) multiplicity (SB: spectroscopic binary; C: Hipparcos component binary - $\rho$ and $\Delta Hp$ in Col. 11; G: Hipparcos acceleration binary; S: Hipparcos suspected non-single - field H61); (8) Hipparcos membership (C: Z99 certain member; P: Z99 possible member; B: Z99 non-member, but B52 member); (9) Hipparcos parallax $\pi$ (H11; mas); (10) Hipparcos parallax error $\sigma _\pi$ (H16; mas); (11) Hipparcos components.
Table 2: Stars used as radial velocity standards. Columns: (1) HD number (Hipparcos Catalogue field H71); (2) Hipparcos identifier (H1); (3) V magnitude (H5); (4) spectral type and luminosity class (H76); (5) number of spectra obtained (N; subtractions refer to rejected exposures due to detector instability); (6) multiplicity (G: Hipparcos acceleration binary; S: Hipparcos suspected non-single - field H61) (7) assumed radial velocity (km s^-1; see Sect. 4.1 for details); (8) idem from Morse et al. (1991; Table 6; Table 4 for HD 23408); (9) radial velocity in km s^-1 from Fekel (1985; Table 3); (10) idem from Wolff (1978; range < $3 \cdot {\rm standard~deviation}$ ; Tables 1 and 3); (11) idem from Abt & Levy (1978; Table 1); (12) idem from Gies & Bolton (1986; Table 3); (13) idem from Latham & Stefanik (1982; Table 1).
Table 3: Radial velocities for 29 target stars. Each star occupies N lines, with N the number of spectra/exposures obtained (Table 1). Columns: (1) HD number; (2) spectral type and luminosity class; (3) multiplicity (SB: spectroscopic binary; C: Hipparcos component binary; G: Hipparcos acceleration binary; S: Hipparcos suspected non-single - field H61); (4) the number of suitable standard stars $N_{\rm s}$ and, between brackets, the associated total number of exposures $N_{\rm e}$ (Sect. 4.4); (5) the average distance to the $N_{\rm s}$ standard stars (Sect. 4.6); (6) exposure number ( $1,\ldots,N$ ; asterisks denote suspect exposures related to detector instability - see Sect. 3 for details); (7) heliocentric Julian date of the mid-point of the exposure (HJD 24507XX.XXXXX); (8) final distance-weighted radial velocity $v_{\rm rad}$ (km s^-1; Eq. (3) in Sect. 4.4); (9) corresponding standard deviation $\sigma _{v,{\rm rad}}$ (km s^-1; Sect. 4.6); (10) time-averaged radial velocity $\overline {v}_{\rm rad}$ using the N exposures (km s^-1; spectroscopic binaries show a dash; Sect. 4.6); (11) corresponding standard deviation $\sigma _{\overline {v},{\rm rad}}$ (km s^-1; values smaller than 2.0 km s^-1 are optimistic; Sect. 4.6); (12) literature radial velocity (km s^-1); (13) source of literature radial velocity (Col. 12) and remarks (B52: Blaauw 1952; BvA: Blaauw & van Albada 1963; Z83: Zentelis 1983).
Table 4: Illustration of results underlying the mean radial velocities $v_{\rm rad}$ in Table 3 (cf. Eq. (3)). The star HD 24970 (A0) was observed N = 3 times and has $N_{\rm s} = 5$ suitable standard stars, giving rise to 5 radial velocities per exposure. These values are listed (in km s^-1), together with the spectral classifications and distances d and weights w (see Eqs. (1) and (4)) of the standard stars. The distance-weighted mean radial velocities with their errors are listed in the final column (in km s^-1). Systematic differences between columns in this table can be due to template mismatch and/or incorrect literature radial velocities; in general, systematic differences between lines in this table can be due to random errors (statistics), instrumental shifts, and/or multiplicity (not likely in this specific case).
Table 5: The standard deviations of the radial velocities corresponding to the $N_{\rm e}$ different exposures of the $N_{\rm s} = 5$ suitable standard stars for all combinations of the different object exposures and suitable standard stars of the stars HD 24970 (A0; cf. Table 4; top part) and HD 23268 (A0; bottom part). The distance-weighted mean radial velocities with their errors are listed in the final column (in km s^-1); time-averaged values, denoted $\overline {v}_{\rm rad}$ , are provided in Table 3. The quantity $\sigma _{\rm r}$ denotes the repeatability error (Sect. 4.3).
Table 6: The five spectroscopic binaries (SBs) and their orbital elements. Columns for the first part of the table (literature data): (1) HD number; (2) periastron date T₀ (HJD); (3) period P (days); (4) primary orbital semi-amplitude K₁ (km s^-1); (5) secondary orbital semi-amplitude K₂ (km s^-1; only for double-lined spectroscopic binaries, i.e., SB2s); (6) systemic velocity $\gamma$ (km s^-1); (7) orbital eccentricity $\epsilon$ (see the footnote to the table for literature sources). Columns for the second part of the table (data from this study): (1) HD number; (2) exposure number (Table 3); (3) instantaneous radial velocity (km s^-1); (4) primary component prediction using the ephemeris provided above (km s^-1); (5) secondary component prediction using the ephemeris provided above (km s^-1; only for SB2s).
Table 7: Membership and photometry of Per OB2. We first list the 29 objects observed by us (cf. Table 1). Below the horizontal line, we added two classical members from B52 that were not observed (Sect. 5.2.1) and three members from Z99 for which literature radial velocities exist (Sect. 5.2.3). Columns: (1) HD number; (2) spectral type; (3) classical membership assignment (B52; C: certain member; P: possible member; N: non-member); (4) Hipparcos membership (Z99); (5) membership based on radial velocity (mostly this work); (6) final membership, based on Cols. 4 and 5; in the case labeled with an asterisk, also photometric information was used; (7) Johnson B magnitude (from Tycho); (8) Johnson V magnitude (from Tycho); and (9) visual extinction A_V from Strömgren or Johnson photometry (Sect. 5.4). We do not list photometric data for eight clear non-members (Sect. 5.4). Membership for the run-away star $\xi$ Per (HD 24912) comes down to semantics; we have indicated it by the label R.