4 Notes on individual sources

  HK Ori: a cooler companion is detected thanks to the strong Li I 6708Å line and other metallic lines. This was previously found by Davis et al. (1981). The rotational velocity of the companion is $\approx\!20\,\pm$3$\mathrm{km\,s}^{-1}$, the equivalent width (EW) of the Li line is 170$\,\pm\,$10mÅ.

The broad He I 6678Å line from the primary is blended with the Fe I 6680Å absorption line from the secondary. No radial velocity variations were recorded during our spectroscopic survey.

HK Ori is also known to be a visual binary (separation $\rho_\mathrm{vis}=0.34\hbox{$^{\prime\prime}$}$, see Leinert et al. 1997b). An important point is that the Li I detection and the presence of Ca I 6103 and 6122Å lines of the companion confirms its youth and lower mass. In the discussion of the system by Leinert et al. (1997b), the case a) seems appropriate: the companion is a T Tauri star. A more detailed study of this interesting HAeBe binary system will be given in Bouvier et al. (1998).

V380 Ori: as already claimed by Corcoran & Ray (1995), Li I line is present in its spectrum: the companion has a rotational velocity of 30$\,\pm\,$5$\mathrm{km\,s}^{-1}$, EW$=80\,\pm\,10$mÅ for the Li I line. Ca I 6103 and Ca I 6122Å absorption lines from the companion are also detected. V380 Ori is a visual binary ($\rho_\mathrm{vis}=0.15\hbox{$^{\prime\prime}$}$) as well. An analysis of its characteristics will be presented in Bouvier et al. (1998).

V586 Ori: while the He I 6678Å line, due to the HAeBe primary, is clearly visible and broad, we also detect for the first time weak Li I and Ca I 6717Å lines, indicative of a cooler companion. Bouvier et al. (1998) indeed confirm the presence of a T Tauri companion at a separation of $\rho_\mathrm{vis}=1\hbox{$^{\prime\prime}$}$. Secondary rotational velocity is about 30$\mathrm{km\,s}^{-1}$ and Li I EW is around 50mÅ.

NX Pup (A+B): this star is in fact a triple system, consisting of a close binary ($\rho_\mathrm{vis}=0.13\hbox{$^{\prime\prime}$}$, components A+B, Bernacca et al. 1993; Brandner et al. 1995) associated to a distant companion ($\rho_\mathrm{vis}=7\hbox{$^{\prime\prime}$}$) (component C). We spectroscopically observe the close binary for the fist time.

While they detected Li I line in companion C, Brandner et al. (1995) failed to detect lithium in the A+B pair. Our spectrum clearly shows for the first time this line in the binary system, confirming the youth of the system as proposed by Schoeller et al. (1996) on the basis of high angular resolution optical and near infrared images. Both Li I (FWHM = 1.5Å, EW = 120mÅ) and Ca I lines are rather broad (FWHM = 2Å), and may results from a blend of line from both components.

Higher S/N spectra with high resolution are needed to further investigate the spectral type of both components.

HD 203024: the Li I line has an EW of 70mÅ, the rotational velocity of the low-mass companion (first spectroscopic detection) is $\approx$40$\mathrm{km\,s}^{-1}$. HD 203024 is also a visual binary with separation $\rho_\mathrm{vis}=0.3\hbox{$^{\prime\prime}$}$ (Bouvier et al. 1998).

MWC 863: a cool companion is revealed in Li I as well as in other Ca I line (6717, 6103 and 6122Å). The Li I has an EW $\approx$ 40mÅ, the rotational velocity of the secondary is around 30$\mathrm{km\,s}^{-1}$. Besides this new spectroscopic detection, MWC 863 is known to be a visual binary with $\rho_\mathrm{vis}=1.1\hbox{$^{\prime\prime}$}$ (Reipurth & Zinnecker 1993).

TY CrA: this young triple system has been extensively spectroscopically surveyed (Lagrange et al. 1993; ,Corporon et al. 1994, 1996; Beust et al. 1997) and a recent photometric analysis has been made by Casey et al. (1998) and Vaz et al. (1998). It consists of a close central binary ($P \approx$ 2.9days), with a HAeBe primary star and a lower-mass companion; a third much farther away low-mass component orbits the binary. Both lower mass components show Li I absorption line (see Casey et al. 1995; Corporon et al. 1996).

T Ori: this star has already been reported to be a spectroscopic and eclipsing binary by Shevchenko & Vitrichenko (1994). With the present available data, we observe the radial velocity variations but are unable to confirm the proposed period $P\,\approx\,14$ days for the binary system. Further study of this interesting object is needed to obtain precise masses and radii as it has been done for TY CrA.

HD 53367: Herbst & Assousa (1977) and Finkenzeller & Mundt (1984) already reported radial velocity variations for this star. Here, periodic radial velocity variations are reported for the first time in He I 4471, 5876, and 6678Å lines: we propose a period of $P \approx 166$days and an eccentricity $e \approx 0.18$ for the orbital motion of the binary system. More data are needed to confirm this tentative orbital solution.

MWC 300: emission in the red part of He I 5876 and 6678Å makes it difficult to measure of the photospheric central absorption, but radial velocity variations are correlated with the Na I 5890 and 5996Å absorption doublet: a monitoring of this star is needed to provide an estimate of the period, our data being to largely spread in time. This is a first detection.

AS 442: periodic radial velocity variations are found in Mg II 4481Å doublet as well as in the Si II 6347 and 6371Å absorption doublet. We found a possible orbital solution with $P \approx 64$days and $e \approx 0.2$, to be confirmed by other observations. This is a first detection.

MWC 361: some evidences of radial velocity variations are found in various lines such as He I 4471, 5876, and 6678 and Mg II 4481Å but the data at hand are not enough to set any period.

MWC 1080: a photometric period of $P \approx 2.9$days has been determined by Shevchenko et al. (1994) and may compatible with our spectroscopic observations (see spectra at ${\rm JD}=2449949.60$ and ${\rm JD}=2449953.59$ at nearly opposite phase). Line profile variations complicate our measurements. Note the very high blue-shift of the photospheric lines: Shevchenko et al. (1994) gave a $\gamma$ velocity of -180 $\mathrm{km\,s}^{-1}$ for the MWC 1080 binary system. Together with T Ori, it is probably the third eclipsing spectroscopic binary with TY CrA and thus deserves further careful observations to constraint the physical parameters of the system.

None of these seven latest stars but TY CrA show a Li I absorption: the companion must be a low mass star with low luminosity - typically few percents of the primary luminosity. A young massif (HAeBe) companion (thus without Li I) would have on the other hand a higher luminosity and its lines should have been detected, unless highly obscured by dust.

Note that HD 53367, MWC 1080 and MWC 361 have all a visual companion. However, these companions are unlikely to be responsible for the radial velocity variations here observed because of the high separation, but rather a tertiary component may be involved in each visual binary system. If the periodic radial velocity variations of these stars are confirmed, then HD 53367, MWC 1080 and MWC 361 are likely hierarchical multiple systems, as TY CrA.

V361 Ori: emission in the blue part of the He I 6678Å line is sometimes present, as seen in Fig. 14: this may compromise a good measurement of the central position of the line. However, we also made measurements on He I 4471 and 5875, and the more "symmetric'' Mg II 4481Å absorption lines. Abt et al. (1991) observed this star (= Brun 760) but considered it to be constant in radial velocity. The velocity curve showed in Fig. 15 is computed with our own measurements; some data (those with the lower sigma) from Abt et al. (1991) are overplotted.

New measurements are however needed to confirm the spectroscopic binarity status of V361 Ori.

MWC 623: Zickgraf & Stahl (1989) found this star to be a binary system with a Li-rich K star, but this property, confirmed here, was not underlined in Thé et al. (1994).

HD 199603: this star is not a classical HAeBe star, no emission lines are seen in its spectrum. It is a well-known spectroscopic and eclipsing binary of $\beta$ Lyr type with a period of P=1.58days (Pedoussault et al. 1984), a property which was not mentioned in Thé et al. (1994).

MWC 147: Vieira & Cunha (1994) classified that this star as a spectroscopic binary with a period P=1year and a circular orbit. They based their study on analysis of H$\alpha$ spectra, with strong emission: our numerous spectra (15 spectra covering 3 years of observations), do not show any radial velocity variation within the error equal to 5$\mathrm{km\,s}^{-1}$, neither in H$\alpha$ nor in other photospheric absorption lines (He I 4471, 5876, Mg II 4481Å). Its spectroscopic binarity status is then doubtful. Note that the IR companion ($\rho_\mathrm{vis}=3.1\hbox{$^{\prime\prime}$}= 900$AU at 290pc, distance form HIPPARCOS data) cannot be responsible for the doubtful radial velocity variations observed by Vieira & Cunha (1994), as its orbital velocity would be near 27 10³$\mathrm{km\,s}^{-1}$ if its orbit is circular.

GU CMa: Figure 19 shows the He I 6678Å line of GU CMa with strongly variable broad features which could sign the possible transit of a rapidly rotating companion. Other lines He I 4471, and 5876Å also show intensity variability, as the H$\alpha$ line. Adding that Shevchenko et al. (1992) classified its photometric light curve as quasi-periodic, this star should be monitored to study possible circumstellar material transit or chromospheric activity.

IL Cep: Shevchenko & Vitrichenko (1994) proposed a photometric period of P=51days but found a constant radial velocity within the error equal to 6$\mathrm{km\,s}^{-1}$, as we do. The eclipsing binary status of this star remains to be confirmed.

RY Ori: the spectral type is F6 as given by SIMBAD: it may be a composite spectrum binary as pointed out by Herbig & Bell (1988) but we lack good quality spectra in the blue to support this view. The Fig. 21 shows its Li I absorption line: if not due to a companion star, RY Ori is more probably a T Tauri star.

  

Figure 20: Spectrum of HD 94509, showing a broad He I 6678.154Å line and other narrow metallic lines, probably originating from the shell. The zoomed windows display the three different narrow lines at JD = 2450821.76, 2450588.48 and 2449822.53 (from top to bottom). Variations in radial velocity are observed

  

Figure 21: Doubtful HAeBe (with Li I 6708Å line detection)

T Cha: this young PMS star has a G8 spectral type: the Li I line detection confirms its youth (Covino et al. 1997). Possible radial variations may be present, however other data are needed to definitively assert this.

HD 94509: this star shows a composite spectrum in the He I 6678Å region. Superimposed on the broad He I 6678Å line, narrow absorption features are seen: we tentatively identified them as Fe I 6677.989, Ca I 6680.628 and Ca I 6717.681Å lines from a cooler companion, but the velocity of each element were not coherent: Fe I was at -45 $\mathrm{km\,s}^{-1}$, Ca I 6681 line at -35 $\mathrm{km\,s}^{-1}$ and Ca I 6717 line at -7 $\mathrm{km\,s}^{-1}$. Furthermore Li I is not detected, making doubtful the identification with a young cool companion. However, remembering that HD 94509 is an A0I shell star (Reed & Beatty 1995), we may consider that the narrow absorption features are metallic lines formed in the shell. If the strong absorption is due to the He I 6678Å line from the shell, its velocity is around -50$\mathrm{km\,s}^{-1}$, while if the two others narrow absorption features are from Fe I 6677.989 and 6715.383Å their respective velocity are $+90\,\pm\,10$$\mathrm{km\,s}^{-1}$. Small radial velocity variations may also be present from one spectrum to another. This star need further study to precise its evolutionary status.

MWC 314: Miroshnichenko (1996) made a detailed analysis of this star and proposed it to be a LBV candidate: MWC 314 is very unlikely a HAeBe star. Our data do not suggest neither the presence of radial velocity variations.