New Elements of Known Variables

A. V. Khruslov
Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia

Received:   22.03.2012;   accepted:   6.09.2012
(E-mail for contact: khruslov@bk.ru)

Comments:


1. VW Men, an L-type star (slow irregular variable) in the GCVS, where the information is based on Knigge (1973), is actually an RRAB star according to ASAS-3 data. M–m = 0.15 P. J–H = 0.117 (2MASS).

2. The variability of TYC 4529 01340 1 was reported by Woźniak et al. (2004b). The variable was classified as an L: star (slow irregular variable), with a period of 298 d. The ROTSE-I/NSVS data they used cover a time interval slightly in excess of one cycle; a double wave was observed in the second cycle. Besides, satisfactory data is very sparse (16 data points), and the ROTSE data with photometric correction flags (usually rejected) show a large scatter of the light curve. For this reason, the derived period was not accurate enough. I investigated the star using my visual observations (123 estimates, JD2453505–2455871; comparison stars: TYC 4529 1150 1, TYC 4529 1592 1, TYC 4525 1811 1, TYC 4529 1201 1; magnitudes of the comparison stars were taken from the Tycho-2 catalog; telescope: 15-cm reflector). Actually, this is a semiregular pulsating star (SR) with a shorter period. The shape of the light curve varies, type SRB is not excluded. This result agrees with the ROTSE-I/NSVS data. B–V = 1.689 (Tycho2), J–H = 0.983 (2MASS). IRAS 06206+7657. The spectral type is from Mickaelian and Gigoyan (2006; star BIS 244).

3. The variability of GSC 1333–00620 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a MISC star with the wrong period of 0.563755 days. I reinvestigated the star using the currently available ASAS-3 and ROTSE-I/NSVS data and found it to be an eclipsing binary star (EA type). D = 0.14 P. A twice longer period is not excluded.

4. The variability of TYC 1380 01260 1 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a MISC star with the wrong period of 0.397738 days. I reinvestigated the star using the currently available ASAS-3 and ROTSE-I/NSVS data and found it to be an eclipsing binary star (EB type). MinII = 11.3.

5. The variability of CC Cha was discovered by Knigge (1973). The variable was classified in the GCVS as an L-type star (slow irregular variable). According to ASAS-3 data, it is an RRAB star. J–H = 0.307 (2MASS).

6. The variability of TYC 8926 00365 1 was reported by Pojmanski (2002). The ASAS-3 catalog lists the variable as an RRAB/DCEP-FO/EC/ED star with the period of 0.575605 days. I reinvestigated the star using the currently available ASAS-3 data and found it to be an eclipsing binary star (EB type) with a twice longer period. MinII = 11.88.

7. CF Cha, an L-type star (slow irregular variable) in the GCVS, where the information was based on Knigge (1973), is actually an eclipsing binary star (EB type) according to ASAS-3 data. MinII = 13.75.

8. The variability of SS Cha was discovered by Hoffmeister (1963). The variable was classified in the GCVS as an eclipsing variable star (EA type) according to Gessner (1980). No period is tabulated there, the time of minimum is given as JD 2436694.258:. I confirm the eclipsing nature of this variable according to ASAS-3 data. The period (see the Table) was determined taking into account the epoch from Gessner (taken alone, the ASAS data give the period P = 11.332 days). D = 0.07 P. Brightness variations at maximum or the presence of a distortion wave characteristic of RS CVn stars are not excluded (a possible period is P = 11.316 days).

9. The variability of EH Mus was reported by Knigge (1973). The variable was classified in the GCVS as an L-type star (slow irregular variable). According to ASAS-3 data, it is an RRAB star. J–H = 0.332 (2MASS).

10. The variability of AG Cha was reported by Hoffmeister (1963). The variable was classified in the GCVS as an eclipsing variable star (EA type), according to Gessner (1980). No period is tabulated there, the time of minimum is given as JD 2436725.260. I confirm the eclipsing nature of this variable (EB type) according to ASAS-3 data. There are too few data points in the primary minimum, and its exact depth remains unknown. Type EA is not excluded. MinII = 14.2.

11. The variability of EU Mus was discovered by Deurinck and Vissenberg (1973). The variable was classified in the GCVS as an RRAB star with the elements HJD 2438529.306 + 0.3121445 x E, M–m = 0.24 P. Layden (1997) gives the following elements for the star: JD 2449082.622 + 0.4526 x E. I confirm the RR Lyrae nature of this variable (RRAB type) according to ASAS-3 data. The period I determined is close to that by Layden. The period suggested by the GCVS is a one-day alias of the true one (see the Table). M–m = 0.14 P. J–H = 0.283 (2MASS). The tabulated amplitude is too low: ASAS-3 measured the combined brightness of two stars, EU Mus = USNO-A2.0 0150-11185274 and a brighter one, USNO-A2.0 0150-11184199 (plus 2MASS 13075281-7112190, with a small contribution).

12. The variability of V592 Cen was discovered by van Gent (1948). The variable was classified in the GCVS as a semiregular pulsating star (SR type) with the period of 40 days; the mean brightness was reported to vary. Lloyd Evans (1985) performed JHKL infrared photometry of V592 Cen and detected properties of RV Tauri stars (type RVB). The color indices he measured (J–H = 0.65–0.76) are close to those of other RVB stars. The 40-day period was considered a half of the true one; the period of long-term mean-brightness variations was not determined. The ASAS-3 catalog lists the star as a MISC variable with the period of 42.2 days. Bidelman and MacConnell (1998) quote the spectral type as earlier than M. I reinvestigated the star using the same ASAS-3 data and confirm the RV Tauri nature of this variable (RVb subtype). The elements of the mean-brightness variability are: JD (max) = 2453150 + 1000 x E. Deep and shallow minima can be distinguished during the maximum mean brightness; at the low mean brightness, the two minima have the same depth, typical of RVb stars. B–V = 1.428 (Tycho-2), J–H = 0.753 (2MASS). IRAS 13054–5907.

13. The variability of GSC 1451–00599 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a MISC star with the wrong period of 1.0 days. I reinvestigated the star using the currently available ASAS-3 data and found it to be a semiregular pulsating star (SR type), J–H = 0.866 (2MASS). IRAS 13161+1534. The spectral type is from Stephenson (1986; star StM 180). According to Lee et al. (1947; star DO 14723), the spectral type is M2.

14. The variability of BT Cen was discovered by Hoffleit (1930). The variable was classified in the GCVS as an RR: star without light elements. According to ASAS-3 data, it is an RRAB star. M–m = 0.15: P. J–H = 0.262 (2MASS).

15. The variability of GSC 8252–01625 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a MISC/SR star with the period of 100.955154 days. I reinvestigated the star using the currently available ASAS-3 data. It is actually an SRD star. J–H = 0.577 (2MASS). The period is much shorter than that listed in the ASAS-3 catalog. The period noticeably changed (or a phase jump occurred) about JD 2452400, as it is clearly seen from the phased light curve. The shape of the light curve varies; sometimes, a barely noticeable secondary minimum appears at phase 0.5.

16. The variability of EL Cen was reported by Hoffleit (1930). The variable was classified in the GCVS as an eclipsing variable star (E type) without light elements. I confirm the eclipsing nature of this variable according to ASAS-3 data. MinII = 12.55 . This is an eccentric binary system, the phase of MinII is 0.312 P. The minima differ in duration: DI = 0.012 P, DII = 0.022 P.

17. The variability of TYC 6121 00132 1 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a MISC star with the wrong period of 1.17348 days. I reinvestigated the star using the same ASAS-3 data. It is actually an eclipsing variable star (EA/RS type). D = 0.05 P. A distortion wave characteristic of RS CVn stars overlaps the eclipsing light curve. The elements of the distortion wave are: Max = JD 2453603.7 + 6.6315 x E. The bottom part of the figure shows how the wave moves along the eclipsing light curve. The amplitude of the distortion wave can be as large as 0.2m, but it changes somewhat (it was noticeably smaller in 2008–2009), attributable to the presence of a second wave, with the elements Max = JD 2453603.0 + 6.663 x E and an amplitude below 0.1 mag. 1RXS J133030.3–155138.

18. The variability of HK Cen was reported by Hoffleit (1930). The variable was classified in the GCVS as an eclipsing variable star (E/SD: type) without light elements, a probable period being 7/N days. I confirm the eclipsing nature of this variable (EA type) according to ASAS-3 data. MinII = 12.55. D = 0.13 P.

19. The variability of HR Cen was discovered by Hoffleit (1930). The variable was classified in the GCVS as an RR star without light elements. I confirm the RR Lyrae nature of this variable (possible RRAB type) according to ASAS-3 data. J–H = 0.272 (2MASS).

20. The variability of IL Cen was discovered by Hoffleit (1930). The variable was classified in the GCVS as an S: star. It is actually a semiregular star (SR type). The long-term pulsations are overlapped with brightness variations with a period about 50 days. IRAS 13545–5202. J–H = 1.036 (2MASS).

21. The variability of SV Cir was reported by Swope (1931). The variable was classified in the GCVS as an eclipsing variable star (E/SD: type) without light elements, with the magnitude range 13.0–15.0 (p). I confirm the eclipsing nature of this variable (EA type) according to ASAS-3 data. D = 0.12 P.

22. The variability of BK Cir was reported by Hoffmeister (1966). The variable was classified in the GCVS as a possible semiregular pulsating star without light elements. According to ASAS-3 data, it is an SRD star. J–H = 0.692 (2MASS).

23. UW Lup, an S: type star (variable star with rapid variations) in the GCVS, where the information was based on Mohr (1929), is actually a Cepheid (possibly a CWA star) according to ASAS-3 data. M–m = 0.29 P. J–H = 0.651 (2MASS). IRAS R14478–5024. The star is close to the galactic plane (b = +7.9), and thus the DCEP type is not excluded.

24. The variability of AD Lup was discovered by Mohr (1929). Its type is not indicated in the GCVS. According to ASAS-3 data, it is an eclipsing variable star (EA/RS type). MinII = 13.5. A distortion wave characteristic of RS CVn stars overlaps the eclipsing light curve. 1RXS J151025.2–472511.

25. The variability of GSC 149400222 was reported by Pojmanski (2002). The ASAS-3 catalog lists the variable as a MISC star with the wrong period of 40.740831 days. I reinvestigated the star using the same ASAS-3 data plus data from ROTSE-I/NSVS and Catalina (Drake et al. 2009) surveys. It is actually a short-period eclipsing variable star (EA type). MinII = 13.30 (CV). A total eclipse is probably observed in the primary minimum.

26. The variability of OZ Ser (HIP 076296) was discovered by the Hipparcos mission (ESA 1997). The variable was classified in the GCVS as an LB star (slow irregular variable). The ASAS-3 catalog lists the variable as a MISC star with the wrong period of 1.0 days. I reinvestigated the star using the same ASAS-3 data. Ii is actually a semiregular pulsating star (SR). Our period cannot be confirmed from Hipparcos data. B–V = 1.692 (Tycho2), J–H = 1.008 (2MASS). IRAS 15325+0054. The spectral type is from Lee et al. (1947; DO 3777).

27. The variability of BR Nor was discovered by Hoffleit (1931). The variable was classified in the GCVS as an S: star. It is actually a eclipsing variable star according to ASAS-3 data. MinII = 12.85. ASAS presents the combined brightness of BR Nor and USNO-A2.0 0300-26450521, and thus the tabulated amplitude is too low; the primary minimum is probably deeper, and the star belongs to the EB type, as confirmed by its blue color index, J–H = 0.166 (2MASS).

28. The variability of LX Nor was discovered by Hoffmeister (1963). The variable was classified in the GCVS as an eclipsing variable star (E type) according to Gessner and Meinunger (1975). The time of minimum JD 2436818.280 and possible periods: 0.60492 days, 0.7851 days, etc., are quoted. I confirm the eclipsing (EB) nature of this variable according to ASAS-3 data. MinII = 13.5:. Type EA is not excluded.

29. The variability of DG Nor was discovered by Hoffleit (1931). The variable was classified in the GCVS as an S: star. It is actually an eclipsing variable star (EA type) according to ASAS-3 data. MinII = 13.4, D = 0.14 P. The tabulated amplitude is too low because of the presence of a neighbor, USNO-A2.0 0300-27518332.

30. The variability of DP Nor was discovered by Hoffleit (1931). The variable was classified in the GCVS as an S: star. It is actually an eclipsing variable star (EW type) according to ASAS-3 data. MinII = 14.15.

31. The variability of EL Nor was reported by Hoffleit (1931). The variable was classified in the GCVS as an S: star. It is actually an eclipsing variable star (EB type) according to ASAS-3 data. MinII = 13.75.

32. The variability of CQ TrA was reported by Hoffleit (1931). The variable was classified in the GCVS as an RR star without light elements. I confirm the RR Lyrae classifications of this variable (RRAB type) according to ASAS-3 data. M–m = 0.15 P. J–H = 0.303 (2MASS).

33. The variability of FQ Nor was discovered by Hoffleit (1931). The variable was classified in the GCVS as an RR star with a probable period of 0.682 d. Later, E. Hertzsprung analyzed unpublished observations by the late W.E. Kruytbosch and suggested P = 1.994 d for FQ Nor (Kruytbosch 1936). It is actually a classical cepheid with the period of 2.00632 days, according to ASAS-3 data. M–m = 0.31 P. J–H = 0.374 (2MASS).

34. The variability of DI TrA was discovered by Hoffleit (1931). The variable was classified in the GCVS as an RR: star without light elements. It is actually an eclipsing variable star (EB type) according to ASAS-3 data. MinII = 13.9.

35. The variability of DE Sco was discovered by Swope (1928). Its type is not indicated in the GCVS catalog; the tabulated magnitude range is 13.6–15.1 (p). According to ASAS-3 data, it is an RRAB star. ASAS presents combined brightness of DE Sco and USNO-A2.0 0525-23985130, and thus the tabulated amplitude is much too low. M–m = 0.15 P. J–H = 0.283 (2MASS).

36. The variability of DZ Sco was discovered by Swope (1928). The variable was classified in the GCVS as an S: star. It is actually a periodic variable star (probably of BY type) according to ASAS-3 data. J–H = 0.642 (2MASS).

37. The variability of EK Sco was discovered by Swope (1928). The variable was classified in the GCVS as an S: star. It is actually a semiregular variable star according to ASAS-3 data. J–H = 0.858 (2MASS).

38. The variability of GN Dra (HIP 84896) was discovered by the Hipparcos mission (ESA 1997). The variable was classified in the GCVS as a semiregular variable star (SRB type) without light elements. The Hipparcos catalog also does not present its light elements. I investigated the star using my visual observations (241 estimates, JD2453092–2455871; comparison stars: TYC 4210 00768 1, TYC 4210 00219 1, TYC 4210 00116 1, TYC 4210 00454 1, TYC 4210 00675 1, TYC 4210 00410 1; magnitudes of the comparison stars were taken from the Tycho-2 catalog; telescopes: 15-cm reflector and 5-cm monocular). I confirm the SRB classifications of this variable, with the period of 154 days. I additionally used AFOEV data (4 estimates), available by Internet. B–V = 1.777 (Tycho2), J–H = 0.732 (2MASS). IRAS 17209+6630.

39. The variability of V3070 Sgr was reported by Plaut (1971). The variable was classified in the GCVS as an SR star with no period quoted and JD 2435668 as the time of maximum. I confirm the semiregular classification of this variable (SRD type) according to ASAS-3 data. J–H = 0.704 (2MASS).

40. The variability of V3331 Sgr was reported by Plaut (1971). The variable was classified in the GCVS as an SR star with no period quoted and JD 2436725 as the time of maximum brightness. I confirm the semiregular classification of this variable according to ASAS-3 data. J–H = 0.809 (2MASS). The amplitude is probably too low because of the neighboring stars GSC 7397-01673 and 2MASS 18262473-3155370.

41. The variability of V2402 Sgr was reported by Kooreman (1965). The variable was classified in the GCVS as an I (irregular) star. According to ASAS-3 data, it is a semiregular variable star. J–H = 0.754 (2MASS). IRAS F19007–3221.

42. The variability of AS Oct was reported by Hoffmeister (1963). The variable was classified in the GCVS as an RRAB star with wrong period 0.4143 days (one-day alias of the true one) according to Gessner (1981). Gessner's times of maxima quite agree with the derived period (if taking them into account, P = 0.7084953 days). M–m = 0.25 P. J–H = 0.313 (2MASS).

Remarks:
I present my investigation of 42 known variable stars based on ASAS-3 (Pojmanski 2002), ROTSE-I (Woźniak et al. 2004a) data and my visual observations. All these observations were analyzed using the period-search software developed by Dr. V.P. Goranskij for Windows environment. For the studied stars, previously suggested light elements and/or variability types were found to be wrong. The coordinates were drawn from the GCVS, Tycho-2, or 2MASS catalogs.

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