Peremennye Zvezdy

"Peremennye Zvezdy",
Prilozhenie
,
vol. 11, N 15 (2011)

30 New Chromospherically Active Stars in the ASAS-3 Data Base

K. Bernhard#1,2, S. Otero#3
#1. Linz, Austria;
#2. Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V. (BAV), Berlin, Germany;
#3. American Association of Variable Star Observers

Received:   11.12.2010;   accepted:   18.04.2011
(E-mail for contact: klaus.bernhard@liwest.at, varsao@hotmail.com)


#NameOtherCoord (J2000)TypeMaxMinSystemPeriodEpoch (JD)typeSpCommentL.CurveFind.ChartData
1 GSC 04667-0009000 15 07.58, -03 20 00.2RS11.3111.62V8.8402454768.70min Comm. 1GSC_04667_00090.jpg GSC_04667_00090
2 GSC 08030-0073800 34 06.11, -51 03 01.3RS9.439.71V82.02452243.5min Comm. 2GSC_08030_00738.jpg GSC_08030_00738
3 GSC 05282-0221002 19 47.39, -10 25 40.7RS10.4510.96V8.1152452674.54minK0eComm. 3GSC_05282_02210.jpg GSC_05282_02210
4 GSC 08054-0085902 51 11.38, -47 53 07.9BY11.6712.15V13.272453671.66minK5Comm. 4GSC_08054_00859.jpg GSC_08054_00859
5 GSC 08499-0063903 27 39.75, -58 09 49.9RS10.8011.48V4.0812453654.75minK2IVeComm. 5GSC_08499_00639.jpg GSC_08499_00639
6 GSC 07572-0010903 34 09.58, -41 43 49.8RS11.2311.68V15.302454763.71min Comm. 6GSC_07572_00109.jpg GSC_07572_00109
7 GSC 07570-0152303 59 36.73, -39 53 14.9RS9.429.82V9.9242452093.94minK0Comm. 7GSC_07570_01523.jpg GSC_07570_01523
8 GSC 08868-0198404 00 37.30, -60 13 59.1RS11.7712.21V3.3032452128.81min Comm. 8GSC_08868_01984.jpg GSC_08868_01984
9 GSC 05886-0110104 14 43.35, -18 52 12.5RS9.289.65V61.692454379.8min Comm. 9GSC_05886_01101.jpg GSC_05886_01101
10 GSC 05960-0058606 34 36.36, -21 33 05.7RS12.4013.03V16.1822454459.67min Comm. 10GSC_05960_00586.jpg GSC_05960_00586
11 GSC 04806-0315806 36 56.33, -05 21 03.6BY11.3912.41V5.0282454190.55minK7Comm. 11GSC_04806_03158.jpg GSC_04806_03158
12 GSC 07111-0059807 17 49.81, -33 56 40.1RS12.7613.46V30.582452054.47min Comm. 12GSC_07111_00598.jpg GSC_07111_00598
13 GSC 00186-0114207 36 41.89, +03 54 19.8RS10.9111.42V19.282452946.79min Comm. 13GSC_00186_01142.jpg GSC_00186_01142
14NSV 17584GSC 01370-0045007 45 16.39, +20 23 16.5RS9.589.71V12.1342452678.62minG5Comm. 14GSC_01370_00450.jpg GSC_01370_00450
15 GSC 08601-0338310 35 33.01, -53 52 27.6RS10.7411.05V15.522451914.77min Comm. 15GSC_08601_03383.jpg GSC_08601_03383
16 GSC 07739-0218011 21 05.63, -38 45 16.5BY12.4212.97V3.30342454901.72minM1VeComm. 16GSC_07739_02180.jpg GSC_07739_02180
17 GSC 07222-0055711 57 48.75, -33 35 53.3RS10.8011.19V56.92452782.6min Comm. 17GSC_07222_00557.jpg GSC_07222_00557
18 GSC 08216-0242711 58 23.41, -45 57 31.3RS11.6511.98V8.8702451913.82min Comm. 18GSC_08216_02427.jpg GSC_08216_02427
19NSV 19379GSC 09412-0077612 24 47.78, -75 03 09.4BY10.4310.79V8.3082455023.578minK3VeComm. 19GSC_09412_00776.jpg GSC_09412_00776
20 GSC 00881-0065712 35 57.41, +13 29 25.3RS10.0710.53V4.5312452793.52min Comm. 20GSC_00881_00657.jpg GSC_00881_00657
21 GSC 08346-0203417 36 04.03, -47 10 09.8RS10.1410.69V12.5202451949.89minK1IIIeComm. 21GSC_08346_02034.jpg GSC_08346_02034
22 GSC 07896-0229917 36 51.68, -44 20 06.8RS9.9510.27V41.32452135.5min Comm. 22GSC_07896_02299.jpg GSC_07896_02299
23 GSC 00424-0195217 46 25.44, +03 58 48.9RS9.419.67V8.4472454383.45min Comm. 23GSC_00424_01952.jpg GSC_00424_01952
24NSV 24393GSC 06856-0195618 19 52.21, -29 16 32.8RS8.748.95V0.5708322454245.770minG5VComm. 24GSC_06856_01956.jpg GSC_06856_01956
25 GSC 00450-0006418 32 18.96, +02 14 54.0RS11.2011.90V12.842454375.32minK2IIIeComm. 25GSC_00450_00064.jpg GSC_00450_00064
26 GSC 07967-0120320 45 11.53, -40 49 57.6RS10.6010.97V3.59132452810.74min Comm. 26GSC_07967_01203.jpg GSC_07967_01203
27 GSC 07967-0042020 45 36.81, -39 49 56.8RS9.8210.21V12.402452031.93minK0IIIeComm. 27GSC_07967_00420.jpg GSC_07967_00420
28 GSC 09112-0027720 46 55.64, -66 53 00.2RS10.5710.92V39.532452085.8min Comm. 28GSC_09112_00277.jpg GSC_09112_00277
29 GSC 07476-0071321 12 19.05, -33 36 20.2RS12.4013.05V9.1432452088.74min Comm. 29GSC_07476_00713.jpg GSC_07476_00713
30 GSC 05226-0118022 20 29.92, -01 39 58.2RS12.1412.71V9.0972452494.71min Comm. 30GSC_05226_01180.jpg GSC_05226_01180

Comments:


1. Johnson B–V = 1.423 (derived from Tycho-2); J–K = 0.756 (2MASS).
Proper motion: pmRA = 14.1 mas/yr, pmDE = –1.2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J001507.4–032010, HR1 = 0.78, HR2 = 0.07.
ASAS variable type: DCEP-FU/ELL.

2. Johnson B–V = 1.050 (derived from Tycho-2); J–K = 0.671 (2MASS).
Proper motion: pmRA = 7.7 mas/yr, pmDE = 4.0 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J003408.1–510305, HR1 = –0.08, HR2 = 0.24.
ASAS variable type: EC/ESD.

3. Johnson B–V = 1.076 (derived from Tycho-2); J–K = 0.762 (2MASS).
Proper motion: pmRA = 14.9 mas/yr, pmDE = –1.7 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J021944.9–102549, HR1 = 0.51, HR2 = 0.30.
Spectral type: K0e (White et al. 2007).
Spectroscopic binary; period = 8.1194 d, (Pourbaix et al. 2004).
ASAS variable type: DCEP-FO.

4. J–K = 0.834 (2MASS).
Proper motion: pmRA = 3.2 mas/yr, pmDE = –2.2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J025111.7–475314, HR1 = 0.41, HR2 = 0.11.
Spectral type: K5 (Riaz et al. 2006).
ASAS variable type: DCEP-FU.

5. Johnson B–V = 1.076 (derived from Tycho-2); J–K = 0.781 (2MASS).
Proper motion: pmRA = 77.1 mas/yr, pmDE = 70.2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J032738.6–580937, HR1 = 0.78, HR2 = 0.68.
Spectral type: K2IVe, EW(Li) = 110 (Torres et al. 2006).
ASAS variable type: DCEP-FU.

6. J–K = 0.777 (2MASS).
Proper motion: pmRA = 0.7 mas/yr, pmDE = 1.9 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J033411.6–414307, HR1 = 0.90, HR2 = 0.34.
ASAS variable type: DCEP-FU/ELL.

7. Johnson B–V = 1.184 (derived from Tycho-2); J–K = 0.783 (2MASS).
Proper motion: pmRA = 10.2 mas/yr, pmDE = –25.3 mas/yr (Roeser et al. 2010).
Spectral type: K0 (White et al. 2007).
ASAS variable type: DCEP-FU.

8. J–K = 0.790 (2MASS).
Proper motion: pmRA = 0.3 mas/yr, pmDE = –15.0 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J040038.5–601338, HR1 = 1.00, HR2 = 0.19.
ASAS variable type: DCEP-FO/ELL.

9. Johnson B–V = 1.207 (derived from Tycho-2); J–K = 0.705 (2MASS).
Proper motion: pmRA = –0.8 mas/yr, pmDE = –3.8 mas/yr (Roeser et al. 2010).
ASAS variable type: DCEP-FU/SR.

10. J–K = 0.850 (2MASS).
Proper motion: pmRA = –4.0 mas/yr, pmDE = –0.5 mas/yr (Roeser et al. 2010).
ASAS variable type: DCEP-FU/EC.

11. Johnson B–V = 0.660 (derived from Tycho-2); J–K = 0.807 (2MASS).
Proper motion: pmRA = 14.2 mas/yr, pmDE = 5.2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J063656.7–052104, HR1 = 0.80, HR2 = 0.35.
Spectral type: K7 (Riaz et al. 2006).
ASAS variable type: MISC.

12. J–K = 0.864 (2MASS).
Proper motion: pmRA = –1.7 mas/yr, pmDE = –1.3 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J071748.9–335658, HR1 = 0.22, HR2 = 0.97.
ASAS variable type: DCEP-FU/EC.

13. Johnson B–V = 0.960 (derived from Tycho-2); J–K = 0.766 (2MASS).
Proper motion: pmRA = –20.5 mas/yr, pmDE = –0.7 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J073642.3+035433, HR1 = 0.67, HR2 = 0.01.
ASAS variable type: DCEP-FU/EC.

14. Johnson B–V = 1.061 (derived from Tycho-2); J–K = 0.675 (2MASS).
Proper motion: pmRA = 5.7 mas/yr, pmDE = –13.8 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J074517.5+202332, HR1 = 0.28, HR2 = 0.07.
Spectral type: G5 (Wright et al. 2003).
ASAS variable type: CW-FU.

15. Johnson B–V = 0.727 (derived from Tycho-2); J–K = 0.662 (2MASS).
Proper motion: pmRA = –5.1 mas/yr, pmDE = 1.3 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J103533.0–535225, HR1 = 0.79, HR2 = 0.08.
ASAS variable type: EC/DCEP-FU.

16. J–K = 0.946 (2MASS).
Proper motion: pmRA = –50,2 mas/yr, pmDE = –0,2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J112105.2–384529, HR1 = –0.03, HR2 = –0.17.
Spectral type: M1Ve, EW(Li) = 550 (Torres et al. 2006).
ASAS variable type: DCEP-FU/DCEP-FO.

17. Johnson B–V = 0.992 (derived from Tycho-2); J–K = 0.733 (2MASS).
Proper motion: pmRA = –9.6 mas/yr, pmDE = 0.7 mas/yr (Roeser et al. 2010).
ASAS variable type: DCEP-FU/EC/ESD.

18. J–K = 0.837 (2MASS).
Proper motion: pmRA = –35.8 mas/yr, pmDE = –15.4 mas/yr (Roeser et al. 2010).
ASAS variable type: DCEP-FU/EC.

19. Johnson B–V = 1.020 (derived from Tycho-2); J–K = 0.689 (2MASS).
Proper motion: pmRA = –204.8 mas/yr, pmDE = 46.2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J122447.4–750309, HR1 = –0.09, HR2 = –0.12.
Spectral type: K3Ve, EW(Li) = 0, remark: SB2 (Torres et al. 2006).
Period = 0.8899 d (Koen et al. 2002).

20. Johnson B–V = 1.044 (derived from Tycho-2); J–K = 0.72 (2MASS).
Proper motion: pmRA = –15.1 mas/yr, pmDE = –36.2 mas/yr (Roeser et al. 2010).
ROSAT: 1WGA J1235.9+1329 (White et al. 2000).
ASAS variable type: CW-FO/CW-FU/EC.

21. Johnson B–V = 1.421 (derived from Tycho-2); J–K = 0.830 (2MASS).
Proper motion: pmRA = –1.9 mas/yr, pmDE = –3.9 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J173603.8–471016, HR1 = 0.51, HR2 = 0.08.
Spectral type: K1IIIe, EW(Li) = 0, SB3? (Torres et al. 2006).
ASAS variable type: DCEP-FU.

22. Johnson B–V = 0.995 (derived from Tycho-2); J–K = 0.775 (2MASS).
Proper motion: pmRA = 1.8 mas/yr, pmDE = –2.0 mas/yr (Roeser et al. 2010).
ROSAT: 2RXP J173651.1–442007.
ASAS variable type: EC/DCEP-FU/ESD/SR.

23. Johnson B–V = 0.933 (derived from Tycho-2); J–K = 0.745 (2MASS).
Proper motion: pmRA = –60.3 mas/yr, pmDE = –52.4 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J174625.4+035852, HR1 = 1.00, HR2 = 0.22.
ASAS variable type: DCEP-FU.

24. Johnson B–V = 0.675 (derived from Tycho-2); J–K = 0.473 (2MASS).
Trigonometric parallax: 13.25 +/– 1.41 milliarcseconds (Hipparcos Catalog). Distance: 75.5 +/– 8.0 parsecs (246 +/– 26 light years). Luminosity: 1.54 +/– 0.33 times that of the Sun. Absolute magnitude: 4.33 +/– 0.23.
Proper motion: pmRA = 3.1 mas/yr, pmDE = –46.8 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J181952.6–291623, HR1 = 0.06 , HR2 = 0.21.
Spectral type: G5V, EW(Li) = 290 (Torres et al. 2006).
ASAS variable type: RRAB/ESD.

25. Johnson B–V = 1.389 (derived from Tycho-2); J–K = 0.929 (2MASS).
Proper motion: pmRA = 15.6 mas/yr, pmDE = –20.6 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J183219.2+021456, HR1 = 0.81, HR2 = 0.25.
Spectral type: K2IIIe, EW(Li) = 180 (Torres et al. 2006).
ASAS variable type: DCEP-FU.

26. Johnson B–V = 1.227 (derived from Tycho-2); J–K = 0.784 (2MASS).
Proper motion: pmRA = 37.6 mas/yr, pmDE = –16.0 mas/yr (Roeser et al. 2010).
ASAS variable type: CW-FU.

27. Johnson B–V = 0.942 (derived from Tycho-2); J–K = 0.735 (2MASS).
Proper motion: pmRA = 1.9 mas/yr, pmDE = –1.2 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS J204535.3–394939, HR1 = 0.17, HR2 = –0.02.
Spectral type: K0III(e), EW(Li) = 80, remark: SB2 (Torres et al. 2006).
ASAS variable type: CW-FU.

28. Johnson B–V = 1.228 (derived from Tycho-2); J–K = 0.772 (2MASS).
Proper motion: pmRA = –8.8 mas/yr, pmDE = –21.3 mas/yr (Roeser et al. 2010).
ASAS variable type: CW-FU.

29. J–K = 0.816 (2MASS).
Proper motion: pmRA = –25.9 mas/yr, pmDE = –21.3 mas/yr (Roeser et al. 2010).
ROSAT: 1RXS-F J211220.3–333622, HR1 = 0.65, HR2 = 1.00.
ASAS variable type: CW-FU.

30. J–K = 0.777 (2MASS).
Proper motion: pmRA = 7.9 mas/yr, pmDE = –16.0 mas/yr (Roeser et al. 2010).
ASAS variable type: CW-FU.

Remarks:
30 new RS CVn and BY Dra variables were found by the investigation of ASAS-3, light curves (Pojmanski 2002). Each object was checked against the Strasbourg CDS Vizier service and the International Variable Star Index for pre-existence as a chromospherically active star in variability catalogues.

The criteria for including a star in this list of RS CVn stars after an analysis of the available data with Period 04 (Lenz and Breger 2005) were:

i) period, amplitude and shape of the light curve are consistent with the definition of RS CVn and BY Dra in the GCVS;

ii) appropriate spectral types, 2MASS J–K (Skrutskie et al. 2006) and B–V (Høg et al. 2000) colour indices;

iii) the X-ray identifications (Voges et al. 1999; Voges et al. 2000);

iv) the relation of the maximum amplitude vs. periods of main sequence stars given in Messina et al. (2003);

v) further information like the lithium content as indicator of young stellar objects and proper motions.

According to the definitions of the GCVS, chromospherically active stars of the BY Dra type are emission line dwarfs (single or binary), which have spectral types K–M. RS CVn variables are chromospherically active binary systems which have spectral types of F–K (many of these systems contain a subgiant or giant component). Spectral information and the relation of the maximum amplitude vs. periods of main sequence stars given in Messina et al. (2003) were used to distinguish between these two types.

Some of these chromospherically active stars showed a clear variation of the shape of the light curves. For these objects the ephemeris and the folded light curves are given for a distinct period of time (described in figure as HJD 245....–....). This is somewhat typical of chromospherically active stars which can show secular variation in mean magnitude and/or amplitude as a result of starspot cycles similar in nature to the Suns`s sunspot cycle.

Acknowledgements: This research has made use of the SIMBAD and VizieR databases operated at the Centre de Données Astronomiques (Strasbourg) in France, of the Smithsonian/NASA Astrophysics Data System, of the International Variable Star Index (AAVSO) and of the Two Micron All Sky Survey. It is a pleasure to thank John Greaves, UK for his suggestions and helpful comments.

References:
Høg, E., Fabricius, C., Makarov, V.V., et al., 2000, Astron. Astrophys., 355, L27
Koen, C., Eyer, L., 2002, Monthly Notices of the Royal Astron. Soc., 331, 45
Lenz, P., Breger, M., 2005, Comm. in Asteroseismology, 146, 53
Messina, S., Pizzolato, N., Guinan, E. F., Rodonò, M., 2003, Astron. Astrophys., 410, 671
Pojmanski, G., 2002, Acta Astronomica, 52, 397
Pourbaix, D., Tokovinin, A.A, Batten, et al., 2004, Astron. Astrophys., 424, 727
Riaz, B., Gizis, J.E., Harvin, J., 2006, Astron. J., 132, 866
Roeser, S., Demleitner, M., Schilbach, E., 2010, Astron. J., 139, 2440
Skrutskie, M.F., Cutri, R.M., Stiening, R., et al., 2006, Astron. J., 131, 1163
Torres, C.A.O., Quast, G.R., da Silva, L., et al., 2006, Astron. Astrophys., 460, 695
Voges, W., Aschenbach, B., Boller, Th., et al., 1999, Astron. Astrophys., 349, 389
Voges, W., Aschenbach, B., Boller, T., et al., 2000, IAU Circ., No. 7432
White, N.E., Giommi, P., Angelini, L., 2000, The WGACAT version of ROSAT sources, (Laboratory for High Energy Astrophysics (LHEA/NASA), Greenbelt), Centre de Donnees Astronomiques de Strasbourg, IX/31
White, R.J., Gabor, J.M., Hillenbrand, L.A., 2007, Astron. J., 133, 2524
Wright, C.O., Egan, M.P., Kraemer, K.E., Price, S.D., 2003, Astron. J., 125, 359



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