Comments:
1. The variability of V449 Per was discovered by Hoffmeister (1967). The
information presented in the GCVS is based on Busch et al. (1979):
Algol (type EA/KE), Min = JD 2438739.276 + 0.946204 x E, 12.7 - 13.3 - 13.3 (p).
According to ROTSE-I/NSVS data, the star actually belongs to the EB type with a
period twice shorter than that suggested in the GCVS.
We derive the normal minimum JD 2451495.084 +/- 0.001 from the NSVS data. To
improve the period, we made use of 9 times of minima published in the IBVS and
the epoch from the GCVS.
V449 Per
| Reference |
JD |
| GCVS |
38739.276 |
| Hübscher et al. 2006 |
49569.5532 |
| Agerer 1999 |
51138.3650 |
| NSVS, this paper |
51495.084 |
| Nelson 2003 |
52517.9391 |
| Hübscher et al. 2005 |
53302.3442 |
| Hübscher et al. 2005 |
53316.5301 |
| Hübscher et al. 2005 |
53407.3731 |
| Hübscher et al. 2006 |
53651.4936 |
| Hübscher et al. 2006 |
53652.4395 |
| Dvorak 2006 |
53683.667 |
Earlier, R.H. Nelson combined all these minima in an O-C diagram with the old
period (http://www.aavso.org/bob-nelsons-o-c-files).
The tabulated elements are in a good agreement with the epoch JD 2452500.905
suggested by Kreiner (2004).
MinII = 12.08. The ROTSE data with photometric correction flags (usually rejected)
were kept for the analysis. The use of these
data considerably increases the number of available observations without deteriorating
quality and allows us to determine the period more
accurately.
2. The variability of USNO-A2.0 1425-04674821 was discovered by Hoffman et al. (2009).
They found the star to be an eclipsing binary (type E)
with the period of 5.93478 d. I reinvestigated the star using the same ROTSE-I
data.
I confirm the eclipsing nature of the variable,
but actually it is an Algol (EA) star with a quite different period (see the
Table) and a secondary minimum away from the phase 0.5, indicating an eccentric
binary.
D = 0.11P. MinII = 13.45:, MinII - MinI = 0.545P.
J-H = 0.292 (2MASS). The ROTSE data with photometric correction flags (usually rejected)
were kept for the analysis, but data points with uncertainties in excess of 0.1m
were removed.
3. The variability of UZ Men was reported by Knigge (1973). The system is listed
in the GCVS as an L-type (slow irregular) variable. Pojmański (2002)
suggested the Cepheid classification with the period of 1.0912 d.
Actually, this is an RR Lyrae star (RRC subtype) with a much shorter period.
M-m = 0.33P. J-H = 0.227 (2MASS).
4. The variability of TYC 3036 00098 1 was discovered by Akerlof et al. (2000).
The variable was classified as an RR Lyrae star (RRC subtype),
with the period of 0.21340901 d. I reinvestigated the star using the same ROTSE-I
data
and found it to be an EB eclipsing binary with a twice longer period.
MinII = 12.6. The Tycho2 color index B-V = 0.796 is probably wrong.
J-H = 0.205
(2MASS).
5. The variable is known as SSTc2d J161201.4-384028, a T Tau star,
a young stellar object in the region of dark nebulae
(Krautter et al. 1997, Wichmann et al. 1997, Sartori et al. 2003, Cieza et
al. 2007).
The ASAS-3 catalog (Pojmański, 2002) lists the variable as a Cepheid
(DCEP-FO/DCEP-FU) with the period of 2.814072 d. Our analysis of the ASAS-3
data reveals the presence of brightness variations simultaneously with two
periods:
JD(max) = 2453601.74 + 2.81255 x E,
JD(max) = 2453603.10 + 2.27816 x E.
The object is associated with the X-ray source 1RXS J161201.4-384027.
J-H = 0.625 (2MASS).
Periodic brightness variations of young stars are usually related to axial rotation
of
spotted stars. The simultaneous presence of two periods deserves a special
study.
6. The variability of the star was reported by Pojmański (2002) who found it
to be a Cepheid
with the period of 2.8421 d. Actually, its brightness variations can be
explained as a superposition of an eclipsing light curve charactersitic of
systems with ellipsoidal components and a sine-shaped wave with a slightly
longer period, resembling distorsion waves on the light curves of RS CVn
variables. The light elements for the sine wave are:
JD(max) = 2453601.65 + 2.84455 x E,
and for the eclipsing curve:
JD(min) = 2453600.27 + 2.84304 x E.
The migration period of the wave on the eclipsing phased curve is at least
5000 d.
The variable is associated with the X-ray source 1RXS J173636.6-710652.
B-V = 1.460 (Tycho2), J-H = 0.647 (2MASS).
7. The star's variability was discovered by J.S. Shaw et al. (http://hal.physast.uga.edu/~jss/nsvs/).
The variable
was found to be a
High-Amplitude Delta Scuti star (HADS) with the period of 0.10529850 d.
I reinvestigated the star using the same ROTSE-I data.
The period suggested by Shaw et al. is a one-day alias of the real one
(see the Table).
M-m = 0.37P. B-V = 0.407 (Tycho2), J-H = 0.173 (2MASS).
The ROTSE data with photometric correction flags (usually rejected) were kept for
the analysis.
Remarks:
I present my investigation of seven known variable stars based on ROTSE-I (Woźniak
et
al. 2004) and ASAS-3 (Pojmański 2002) data.
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 wrong.
The coordinates were drawn either from the Tycho-2 or from the 2MASS catalogs.
Acknowledgements: Thanks are due to S.V. Antipin and N.N. Samus for their assistance.
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