3. Results

The aspect data for the observed asteroids may be found in Tables 1-2. The lightcurves of individual asteroids are presented in Figs. 1-18. In the composite lightcurves the individual nights of observations are shifted in magnitude for optimum fit using the method described by Magnusson & Lagerkvist (1990). The actual shifts are given in the small tables appearing within each figure. Below we discuss each object in more detail. The periods and colour indices of each asteroid are given in Table 3. We adopted the albedos and taxonomic types from Tedesco (1989) & Tholen (1989) and give these in the last two columns of Table 3. The present data are a valuable addition to the Asteroid Photometric Catalogue (Lagerkvist et al. 1996).

 

Asteroid Date r Tel/Inst Observer

(UT) AU AU 2000.0 2000.0

8 Flora 1986 Apr. 18.6 2.5221 1.5542 7.8 191.0 9.6 SiS/1-m PM

8 Flora 1993 May 11.2 2.5020 1.5275 7.8 248.9 7.4 ESO/61-cm AE

8 Flora 1993 May 13.2 2.5004 1.5179 7.0 248.4 7.4 ESO/61-cm AE

8 Flora 1993 May 14.2 2.4996 1.5135 6.5 248.2 7.3 ESO/61-cm AE

8 Flora 1993 May 17.2 2.4972 1.5018 5.3 247.4 7.3 ESO/61-cm AE

8 Flora 1993 May 18.2 2.4964 1.4968 4.9 247.2 7.3 ESO/61-cm AE

8 Flora 1993 May 21.2 2.4939 1.4901 3.9 246.4 7.2 ESO/61-cm AE

11 Parthenope 1995 Feb. 2.9 2.6938 1.7093 1.2 130.4 0.7 KVI/1-m TO

11 Parthenope 1995 Feb. 7.9 2.6946 1.7170 3.5 129.2 0.9 KVI/1-m TO

11 Parthenope 1995 Mar. 31.9 2.6969 2.1467 20.0 123.6 1.8 KVI/1-m TO

11 Parthenope 1995 Apr. 1.9 2.6968 2.1590 20.1 123.7 1.8 KVI/1-m TO

11 Parthenope 1995 Apr. 3.9 2.6967 2.1839 20.4 123.9 1.8 KVI/1-m TO

11 Parthenope 1995 Apr. 4.9 2.6966 2.1965 20.5 123.9 1.8 KVI/1-m TO

13 Egeria 1995 Dec. 12.0 2.4351 1.2155 8.8 60.3 11.5 LaP/60-cm TO

13 Egeria 1995 Dec. 28.0 2.4231 1.5862 15.1 57.5 12.5 LaP/60-cm TO

13 Egeria 1995 Dec. 29.0 2.4224 1.5937 15.5 57.3 12.5 LaP/60-cm TO

13 Egeria 1996 Jan. 18.0 2.4084 1.7775 21.0 56.6 12.9 LaP/60-cm TO

13 Egeria 1996 Feb. 1.0 2.3994 1.9322 23.2 57.9 12.9 LaP/60-cm TO

13 Egeria 1997 Feb. 4.1 2.4539 2.0045 22.8 209.1 12.4 KHA/70-cm FV

14 Irene 1994 Oct. 23.3 2.9831 2.0197 5.8 16.3 -12.3 ESO/50-cm JP

25 Phocaea 1995 Sep. 18.2 2.0917 1.2548 19.8 38.8 9.8 ESO/50-cm JP

25 Phocaea 1995 Sep. 19.2 2.0945 1.2595 19.3 38.6 9.7 ESO/50-cm JP

25 Phocaea 1995 Sep. 20.2 2.0973 1.2444 18.9 38.5 9.6 ESO/50-cm JP

64 Angelina 1995 Sep. 22.2 2.7581 1.8490 10.8 29.8 1.8 ESO/50-cm JP

64 Angelina 1995 Sep. 24.2 2.7556 1.8337 8.6 28.8 1.9 ESO/50-cm JP

64 Angelina 1995 Sep. 29.2 2.7493 1.7994 8.2 28.6 1.9 ESO/50-cm JP

71 Niobe 1993 May 11.3 2.3232 1.5579 19.9 274.0 - 31.0 ESO/61-cm AE

71 Niobe 1993 May 14.3 2.3261 1.5391 19.3 273.8 - 31.9 ESO/61-cm AE

71 Niobe 1993 May 16.3 2.3280 1.5273 18.9 273.6 - 32.0 ESO/61-cm AE

71 Niobe 1993 May 17.3 2.3290 1.5217 18.6 273.4 - 32.0 ESO/61-cm AE

71 Niobe 1994 Sep. 21.8 3.1016 2.1670 8.1 4.8 25.1 KVI/1-m TO

71 Niobe 1994 Oct. 3.9 3.1148 2.1907 8.4 1.3 25.8 KVI/1-m TO

71 Niobe 1994 Oct. 5.9 3.1169 2.1984 8.7 1.3 25.8 KVI/1-m TO

71 Niobe 1994 Oct. 10.1 3.1213 2.2179 9.3 0.3 25.9 KVI/1-m TO

71 Niobe 1994 Oct. 25.1 3.1363 2.3229 12.2 357.3 25.6 KVI/1-m TO

110 Lydia 1993 May 13.4 2.6440 1.9503 18.6 289.3 - 4.5 ESO/61-cm AE

114 Kassandra 1993 May 13.4 2.7213 1.9015 14.9 276.2 7.0 ESO/61-cm AE

114 Kassandra 1993 May 15.4 2.7242 1.8862 14.3 276.0 7.1 ESO/61-cm AE

114 Kassandra 1993 May 18.3 2.7283 1.8655 13.4 275.7 7.2 ESO/61-cm AE

114 Kassandra 1993 May 20.3 2.7311 1.8522 12.8 275.5 7.2 ESO/61-cm AE

122 Gerda 1994 Oct. 16.3 3.3076 2.3109 0.3 22.3 - 0.9 ESO/50-cm JP

146 Lucina 1992 Sep. 2.1 2.6990 1.8452 13.8 302.8 - 15.2 ESO/61-cm AE

146 Lucina 1992 Sep. 5.1 2.7010 1.8719 14.6 302.5 - 15.1 ESO/61-cm AE

146 Lucina 1992 Sep. 6.1 2.7017 1.8811 14.9 302.4 - 15.1 ESO/61-cm AE

186 Celuta 1994 Sep. 19.2 2.0100 1.0986 16.4 324.3 -14.2 ESO/50-cm JP

186 Celuta 1994 Sep. 20.2 2.0102 1.1043 16.7 324.2 -14.0 ESO/50-cm JP

233 Asterope 1995 Mar. 05.1 2.9196 1.9661 6.5 147.6 - 10.7 ESO/61-cm AE

233 Asterope 1995 Mar. 07.1 2.9201 1.9745 7.2 147.2 - 10.6 ESO/61-cm AE

233 Asterope 1995 Mar. 09.1 2.9207 1.9840 7.8 146.8 - 10.6 ESO/61-cm AE

233 Asterope 1995 Mar. 11.1 2.9212 1.9946 8.5 146.4 - 10.5 ESO/61-cm AE

233 Asterope 1995 Mar. 26.1 2.9245 2.1044 13.1 144.2 - 9.7 ESO/61-cm AE

 

Asteroid Date r Tel/Inst Observer

(UT) AU AU 2000.0 2000.0

238 Hypatia 1994 Oct. 20.3 2.6835 2.0721 19.2 88.1 - 14.6 ESO/50-cm JP

238 Hypatia 1994 Oct. 21.3 2.6841 2.0617 19.0 88.1 - 14.7 ESO/50-cm JP

238 Hypatia 1994 Oct. 23.3 2.6852 2.0412 18.6 88.2 - 14.9 ESO/50-cm JP

291 Alice 1996 Feb. 18.3 2.1134 1.6021 26.6 222.0 1.4 ESO/61-cm AE+AN

291 Alice 1996 Feb. 22.3 2.1172 1.5607 26.0 222.8 1.4 ESO/61-cm AE+AN

291 Alice 1996 Feb. 23.3 2.1182 1.5505 25.8 222.9 1.5 ESO/61-cm AE+AN

306 Unitas 1996 Feb. 8.3 2.6653 1.7414 9.2 164.3 2.5 ESO/61-cm AE+AN

306 Unitas 1996 Feb. 20.2 2.6561 1.6792 4.1 161.6 3.1 ESO/61-cm AE+AN

306 Unitas 1996 Feb. 24.2 2.6528 1.6673 2.5 160.6 3.3 ESO/61-cm AE+AN

306 Unitas 1996 Feb. 28.2 2.6494 1.6601 1.3 159.6 3.5 ESO/61-cm AE+AN

323 Brucia 1993 May 15.2 2.8188 1.9007 10.5 260.0 17.1 ESO/61-cm AE

323 Brucia 1993 May 16.2 2.8161 1.8907 10.1 259.8 17.0 ESO/61-cm AE

323 Brucia 1993 May 17.2 2.8138 1.8826 9.8 259.5 17.0 ESO/61-cm AE

346 Hermentaria 1993 May 15.0 2.1134 1.6021 26.6 222.0 1.4 ESO/61-cm AE

372 Palma 1994 Aug. 03.3 2.9988 2.2740 15.6 2.7 11.2 ESO/61-cm AE+MG

372 Palma 1994 Aug. 04.3 2.9961 2.2611 15.4 2.7 11.3 ESO/61-cm AE+MG

372 Palma 1994 Aug. 06.2 2.9911 2.2371 15.1 2.6 11.6 ESO/61-cm AE+MG

372 Palma 1994 Aug. 12.3 2.9752 2.1652 13.8 2.3 12.5 ESO/61-cm AE+MG

372 Palma 1994 Aug. 13.2 2.9726 2.1539 13.6 2.2 12.7 ESO/61-cm AE+MG

372 Palma 1994 Aug. 15.2 2.9673 2.1320 13.1 2.0 13.0 ESO/61-cm AE+MG

372 Palma 1994 Aug. 27.3 2.9353 2.0176 10.0 0.4 14.9 ESO/61-cm AE+MG

372 Palma 1994 Sep. 02.3 2.9194 1.9738 8.4 359.3 15.8 ESO/61-cm AE+MG

409 Aspasia 1996 Feb. 11.1 2.5620 1.6110 7.4 149.8 - 18.0 ESO/61-cm AE+AN

435 Ella 1994 Oct. 14.3 2.1029 1.1077 2.5 26.1 0.0 ESO/50-cm JP

435 Ella 1994 Oct. 14.3 2.1062 1.1099 0.2 25.1 0.1 ESO/50-cm JP

435 Ella 1994 Oct. 14.3 2.1095 1.1160 2.2 24.2 0.2 ESO/50-cm JP

435 Ella 1994 Oct. 14.3 2.1104 1.1182 2.7 23.9 0.2 ESO/50-cm JP

512 Taurinensis 1994 Oct. 19.3 1.6474 0.7426 21.7 352.9 -19.7 ESO/50-cm JP

512 Taurinensis 1994 Oct. 20.3 1.6483 0.7479 22.1 352.9 -19.5 ESO/50-cm JP

512 Taurinensis 1994 Oct. 22.3 1.6501 0.7588 22.8 353.0 -19.3 ESO/50-cm JP

512 Taurinensis 1994 Oct. 23.3 1.6510 0.7645 23.2 353.0 -19.2 ESO/50-cm JP

550 Senta 1995 Aug. 9.2 2.0321 1.0623 11.8 334.7 15.9 KVI/1-m TO

550 Senta 1995 Aug. 12.2 2.0335 1.0581 10.8 334.1 16.3 KVI/1-m TO

550 Senta 1995 Aug. 13.2 2.0340 1.0565 10.4 333.9 16.4 KVI/1-m TO

595 Polyxena 1994 Oct. 15.5 3.1946 2.1985 1.0 19.5 -2.1 ESO/50-cm JP

674 Rachele 1992 Sep. 2.1 3.3541 2.5317 11.5 301.6 - 17.4 ESO/61-cm AE

674 Rachele 1992 Sep. 3.1 3.3530 2.5394 11.7 301.5 - 17.3 ESO/61-cm AE

674 Rachele 1992 Sep. 5.1 3.3507 2.5555 12.2 301.3 - 17.2 ESO/61-cm AE

674 Rachele 1992 Sep. 6.1 3.3496 2.5639 12.4 301.2 - 17.2 ESO/61-cm AE

 

Asteroid Period (B-V) Error (U-B) Error (V-R) Error (V-I) Error

(hr) (mag) (mag) (mag) (mag)

8 Flora 12.87 0.91 - - -

11 Parthenope 9.43 0.81 - - -

13 Egeria 7.05 - - - -

14 Irene - 0.82 0.37 0.46 0.85

18 Melpomene - 0.83 0.36 0.45 0.85

24 Themis - 0.71 0.31 0.33 0.67

25 Phocaea - 0.94 0.44 0.48 0.93

28 Bellona - 0.84 0.31 0.45 0.88

31 Euphrosyne - 0.70 0.29 0.37 0.71

42 Isis - 0.86 0.46 0.48 0.89

47 Aglaja - 0.69 0.28 0.36 0.68

48 Doris - 0.73 0.42 0.35 0.66

56 Melete - 0.73 0.33 0.42 0.80

64 Angelina - 0.72 0.26 0.46 0.85

71 Niobe 14.38 - - - -

110 Lydia - 0.71 - - -

114 Kassandra - 0.76 - - -

121 Hermione - 0.73 0.33 0.39 0.75

122 Gerda - 0.84 0.45 0.47 0.94

146 Lucina - 0.70 - - -

186 Celuta - 0.85 0.51 0.47 0.89

233 Asterope 19.743 - - - -

238 Hypatia 8.86 0.78 - - -

287 Nephthys - 0.86 0.38 0.50 0.91

291 Alicia 4.32 - - - -

306 Unitas 8.74 - - - -

313 Chaldea - 0.72 0.31 0.35 0.69

323 Brucia - 0.88 - - -

346 Hermentaria - 0.93 - - -

359 Georgia - 0.74 0.30 0.40 0.83

372 Palma 8.58 - - - -

409 Aspasia 9.02 - - - -

435 Ella 4.624 0.72 0.27 0.38 0.77

451 Patientia - 0.68 0.30 0.36 0.66

487 Venetia - 0.87 0.58 0.46 0.88

505 Cava - 0.67 - - -

512 Taurinensis 5.59 0.93 0.64 0.49 0.92

595 Polyxena 8-9 0.71 - - -

674 Rachele 28.2 0.84 - - -

704 Interamnia - 0.67 0.23 0.34 0.68

8 Flora

  
Figure 1:

In this study, the S-type asteroid (S0-type in Barucci classification) was observed in 1983, at Siding Springs, and in 1993, at La Silla. This asteroid has been observed previously also at several apparitions by Ahmad (1954), van Houten-Groeneveld & van Houten (1958), Veverka (1971), Vesely & Taylor (1985), Zappalá et al. (1983), Harris & Young (1989), Zhou et al. (1982), Hollis et al. (1987), Di Martino et al. (1989) and Debehogne et al. (1990). The asteroid 8 Flora is nearly spherical with low lightcurve amplitude and with a period of 12.86 hours (Harris & Young 1989) or 12.79 hours (Hollis et al. 1987), which is close to the value given by Di Martino et al. (1989) of 12.87 hours. Our data is in favour of the latter period (Fig. 1). The B-V value 0.91 is slightly redder than 0.88 as given by Tedesco (1989).

11 Parthenope

  
Figure 2:

11 Parthenope was observed with the Swedish 60 cm-telescope on La Palma, Canary Islands. 11 Parthenope has been observed previously by van Houten-Groeneveld & van Houten (1958); Wood & Kuiper (1963); Zappalá et al. (1983); Barucci et al. (1985); Harris et al. (1992); Mellillo (1996), and Lang (1996). The period estimation of Barucci et al. (1985), is 7.83 hr but does not agree with the present data. We find that 9.43 hr fits better to present and past observations (Fig. 2). Thus we will adopt the new period for 11 Parthenope. Extensive BV-observations were made on two nights and there was excellent agreement of lightcurves in both colours. Thus there are no major albedo features which cause colour differences at this aspect angle of the asteroid.

13 Egeria

  
Figure 3:

  
Figure 4:

13 Egeria was observed with the Swedish 60 cm-telescope on La Palma, Canary Islands (Fig. 3) and the 70-cm telescope of Kharkov Observatory (Fig. 4). The G-type asteroid 13 Egeria has been observed previously by Chang & Chang (1963) and Licandro et al. (1990). The period derived from these observations by Lagerkvist & Claesson (1996) was 7.0 hours. We find a period of 7.05 hours (Fig. 3).

71 Niobe

71 Niobe has been observed previously by Lustig & Dvorak (1975); Barucci et al. (1985); Harris & Young (1989). The lightcurve of this S-type (S0 in the Barucci classification) is very complicated with three maxima. Unfortunately, our observations include a number of gaps that prevent us from improving the rotational period of the asteroid. According to Lustig & Dvorak (1975) the rotational period is 11.213 hours, and according to Harris & Young (1989) 14.38 hours. This is also consistent with observations by Barucci et al. (1985). The period of 14.38 hours seems to fit our observations best (Figs. 5 and 6).

  
Figure 5:

  
Figure 6:

110 Lydia

110 Lydia has previously been observed quite extensively by Taylor et al. (1971); Dotto et al. (1992) and Lagerkvist et al. (1995). This object is an M-type asteroid (M0 in the Barucci classification). Our observations consist of only a few points for this asteroid.

114 Kassandra

114 Kassandra is a rare T-type asteroid (D3 in the Barucci classification) and has been observed by Gil Hutton & Blain (1988); Harris & Young (1983); Harris & Young (1989) and Harris et al. (1992). According to Harris et al. (1992) the period of the asteroid was determined to be 10.758 hours. Our sparse set of observations agrees with this period (Fig. 7).

  
Figure 7:

146 Lucina

This asteroid has previously been observed during one apparition only by Schober (1983b) and Harris & Young (1989). Asteroid 146 Lucina is a C-type asteroid (C0 in the Barucci classification). Harris & Young (1979) determined the rotational period to be 18.557 hours, which is confirmed by our rather sparse set of observations (Fig. 8). This period was close to the value given by Schober (1983b).

  
Figure 8:

186 Celuta

186 Celuta is an S-type asteroid which has been observed by Lagerkvist (1978a) and Lagerkvist & Petterson (1978). From those observations the period was estimated to be 15 hours by Lagerkvist & Claesson (1996). Our observations of this asteroid consist of only a few points during two nights, and agree with the previous period. The UBVRI-colours for 186 Celuta are to be found in Table 3, and they are in reasonable agreement with those of Tedesco (1989).

233 Asterope

This asteroid is a T-type asteroid (D3 in the Barucci classification) and has previously been observed by Harris & Young (1983) and Lagerkvist et al. (1995b). We find a period of 19.743 hours (Fig. 9), which is consistent with previous estimates.

  
Figure 9:

238 Hypatia

The C-type (C0) asteroid 238 Hypatia has previously been observed during the apparitions of 1981, 1988 and 1991 by Schober (1983b); Lagerkvist et al. (1992); Shevchenko et al. (1992) and Lagerkvist et al. (1995). Colour indices are consistent with the values given by Tedesco (1979). Our data do not allow anything definite to be said about the rotation period. The value of 8.86 hr (Lagerkvist et al. 1995), gives a good fit to our sparse observations (Fig. 10). The B-V value of 0.78 is redder than the value of 0.72 given by Tedesco(1989).

  
Figure 10:

291 Alice

This asteroid was observed by Lagerkvist(1976) and Binzel & Mulholland(1983). From their observations the rotation period is found to be 4.32 hours. Our observations agree fully with this period (Fig. 11). This object is suitable for a determination of the spin vector if data can be obtained during one more apparition.

  
Figure 11:

306 Unitas

The S-type asteroid 306 Unitas was observed previously by Harris & Young(1983) and Hainaut-Rouelle et al. (1995). From our observations the rotation period of this asteroid is found to be 8.74 hours (Fig. 12), which is an improvement over the previous observations. This asteroid is also suitable for a future determination of the spin vector.

  
Figure 12:

323 Brucia

323 Brucia is an S-type asteroid which has been observed by Tedesco(1979) and Schober et al. (1993). A rotational period of 9.46 hours is derived from these observations (Lagerkvist & Claesson 1996). Our observations consist of only a few points during three nights, which fit reasonably well with this period. Our B-V value of 0.88 is close to the value given by Tedesco(1989).

346 Hermentaria

Only a few points during one night were observed for this asteroid. This asteroid has been observed by Harris & Young (1989) and Harris et al. (1992). The B-V value of 0.93 observed by us is redder than the value of 0.83 given by Tedesco (1989).

372 Palma

The BFC-type asteroid 372 Palma has been observed during several apparitions by Zappalá et al. (1983); Haupt & Hanslmeier(1985); Weidenschilling et al. (1990) and Hainaut-Rouelle et al. (1995).

A period of 17.4 hours was preferred in these studies. We find a period of 8.58 hours (Fig. 13), which fits the present and previous data better. The lightcurve of 372 Palma has many fine details as also reported by Hainaut-Rouelle et al. (1995).

  
Figure 13:

409 Aspasia

409 Aspasia is an CX-type asteroid and has been observed also at several apparitions by Lagerkvist(1981); Hanslmeier(1982); Di Martino & Cacciatori(1984) and Hainaut-Rouelle et al. (1995).

The latter two determined a rotational period of 9.03 hours. Our observations give a slightly shorter rotational period of 9.02 hours (Fig. 14).

  
Figure 14:

435 Ella

The DCX-type asteroid 435 Ella has been observed previously during the 1986 apparition by Barucci et al. (1992). They calculated a value of 4.623 hours for the rotation period. The best fit for the lightcurve for our set of data is given by the period of 4.264 hours (Fig. 15). The UBVRI-colours in Table 3 confirm the previous classification of this asteroid. The steep rise of brightness for phase angles under 3 degrees indicates a very steep opposition spike. More observations are needed to confirm this.

  
Figure 15:

512 Taurinensis

512 Taurinensis is an S-type asteroid, with a rotation period of 5.59 hours (Lagerkvist & Claesson 1996). The asteroid has been observed previously during the 1981 apparition by Lagerkvist & Kamél(1982), and Harris et al. (1992). Our observations confirm fully the previous rotation period (Fig. 16). The colour indices also agree with the previous values. The lightcurve has the same type of variability in the secondary maximum as was present in the lightcurve during the 1981 apparition (Lagerkvist & Kamel 1982).

  
Figure 16:

550 Senta

550 Senta has previously been observed during one apparition only by Schevchenko et al. (1992) and Di Martino et al. (1994). Our data are very noisy and do not allow us to say much about this asteroid.

595 Polyxena

We observed 595 Polyxena during one night and no definite period can be determined. The B-V index of 0.71 suggests that 595 Polyxena is a C-type asteroid. This asteroid has been previously observed by Hainaut-Rouelle et al. (1995). They found a rotation period of 5.903 hours, with one maximum for this asteroid. This value does not agree with the present data. We would suggest that the period lies between 8 and 9 hours and that the lightcurve has two maxima (Fig. 17).

  
Figure 17:

674 Rachele

S-type asteroid 674 Rachele has been observed by Harris & Young (1980); Zappalá et al. (1983); Zeigler et al. (1986); Harris & Young (1989) and Harris et al. (1992). Our data seem to support the suggestion by Harris & Young (1979) that the asteroid has a long period of 30.9 hours. We adopt a 28.2 hours period (Fig. 18) if the lightcurve has two maxima and two minima. Our B-V value of 0.84 is slightly bluer than the value of 0.88 given by Tedesco(1979).

  
Figure 18:

Colour observations

In addition to the lightcurves we present here, UBVRI-colours for 14 Irene, 25 Phocaea and 64 Angelina were measured. In addition we publish here the UBVRI-colours of 18 Melpomene, 24 Themis, 28 Bellona, 31 Euphrosyne, 42 Isis, 47 Aglaja, 48 Doris, 50 Virginia, 56 Melete, 121 Hermione, 122 Gerda, 186 Celuta, 287 Nephthys, 313 Chaldaea, 359 Georgia, 451 Patientia, 487 Venetia, 505 Cava and 704 Interamnia (Table II). The (B-V) and (U-B) indices agree quite well with the previous values (Tedesco 1989) except for (U-B) values. We get larger (U-B) values for 487 Venetia and 512 Taurinensis and smaller for 48 Doris, 238 Hypatia and 287 Nephthys. The (V-R) and (V-I) indices were measured for the first time for these object (see Table 3).

Acknowledgements

M.G. likes to thank the DLR for its support during his stay in Chile. E. Braatz assisted during observation runs in La Silla. The stay of J. Piironen at the Astronomical Observatory of Uppsala University was supported by the NorFA foundation (Oslo, Norway) and he wishes to thank Karri Muinonen for valuable help in different phases of the emergency landing back into the astronomical community. The linguistic comments by Vappu Tyyskä are highly appreciated.