Home Page Updated on July 13, 2002
MisV Stars in the TASS Tenxcat DatabaseMay 14, 2000Yoshida, S.; Richmond, M. 1. Initial Research by Seiichi YoshidaThere are many photometric data of stars between Decl. +1.5 deg and -2.4 deg in the TASS tenxcat database, which are available at the TASS web pages. Some of MisV stars, the new variable stars discovered in the MISAO Project, locate in this area. So I searched the TASS database for the data of those MisV stars. Here is the list of MisV stars in this area.
Then I searched the TASS database for these 28 stars. I tried to find the data within 0.02 deg = 1.2 arcmin from the position of each MisV star. As a result, the data of 9 stars are found. The maximum brightness in the MISAO database of those 9 stars are: 10.7, 11.5, 12.1, 12.2, 12.9, 12.9, 13.0, 13.3, 13.4 On the other hand, the maximum brightness in the MISAO database of the rest are: 10.8, 11.8, 12.2, 12.3, 12.5, 12.5, 12.6, 12.7, 12.8, 12.8, 12.9, 13.0, 13.0, 13.2, 13.3, 13.7, 13.8, 13.8, 14.6 I do not know why very bright stars like MisV0130 (10.8 mag at maximum) or MisV0164 (11.8 mag at maximum) were not observed by TASS. Here are the comments on those 9 stars. * MisV0009 = TASS J185911.0-013413
The light curve is very strange. The TASS I-band observations show both the slow fading and short-time eclipse-like fading. The elicpse-like event occurred between 2450995 and 2451022 (JD), with a large amplitude as maximum 10.2 mag and minimum 12.4 mag. The MISAO observations show the brightening. If it is linked to the slow fading observed by TASS I-band, the period is 500 days or more, and it was at minimum around 2451100. But while TASS I-band observations were detecting the slow fading, TASS V-band observations show it was constant, or maybe slightly brightening. * MisV0136 =? TASS 5115-00315
The TASS observations show it is constant. Probably, the TASS observed the nearby star, just southwest of MisV0136. If not, it began to fade out at around 2451100 (JD) after the TASS observations finished, and kept fading for 300 days. * MisV0142 = TASS 5132-00240 = TASS J190049.2-015331
The variability of TASS I-band and V-band are well corresponding, showing the long period variability. It seems to be linked with the MISAO observations. It will be a SR-type variable star with a small amplitude of about 1.3 mag and a period of 400-500 days. * MisV0144 = TASS 5132-00144
The light curve is strange. The TASS V-band observations keep constant, but it was faint sometimes. The TASS I-band observations maybe show the short period variability between 10.5 and 11.5 mag with a rough period of 20-30 days. There are only few MISAO observations. * MisV0250 = TASS J185751.3-015857
The total light curve containing the TASS and MISAO observations shows the long period variability with a period of about 400 days. * MisV0339 =? TASS J185837.2-005406
The TASS observations show it is constant. Probably, the TASS observed the nearby star, just southeast of MisV0339. * MisV0701 = TASS J190030.4-021208 = TASS J190031.2-021212
The total light curve containing the TASS and MISAO observations implies that it is a SR-type with a period of about 300 days. In that case, it must have been at minimum around 2451200 (JD), after the TASS observations and before the MISAO observatinos. But if it keeps fading since 2451050 (JD), the period will be much longer. * MisV0740 = TASS J175944.0-003554
Both the TASS observations and the MISAO observations are detecting the fading for about 100 days. So the period is uncertain. But it will be a long period variable star. * MisV0824 = TASS J175712.0-002846
The TASS observations for 100 days show it was at maximum. The MISAO observations for 300 days show it was at minimum. Therefore, it is a long period variable star with a half period of 450 days from maximum to minimum. 2. Further Research by Michael RichmondYoshida-san mentions some matches between variable stars seen by MISAO and seen by TASS. He found matches in 9 out of 28 cases, and wondered why 19 of the stars weren't found in the TASS database. Let me explain, star by star. In some cases, the stars were seen by TASS cameras, but fewer than 10 times. Only stars observed at least 11 times were placed into the "tenxcat" catalogue, which is available for public viewing and searching.
All measurements here are "raw" magnitudes. They have not been corrected to place them on the standard Johnson-Cousins scale. V-band should be close to the standard, but I-band may be different. The numbers labelled "tass_id" are internal ID numbers in the complete TASS database; they do not correspond to the numbers in the public "tenxcat" catalog. MisV0130 = tass_id 12050621
Julian Date|I-band
-----------------------+------
2450938.863679| 9.806
2450928.89104| 9.794
2450928.893379| 9.912
2450952.8297| 9.933
2450951.829239| 9.894
2451022.63779| 9.85
2450995.714019|10.095
2450640.68746| 9.938
2451027.62611| 9.918
MisV0138 = 12198734
Julian Date|I-band
-----------------------+------
2450961.800679|10.248
2450995.713279|10.328
2450967.79057|10.426
2450951.82849| 10.41
2450952.82896| 10.25
2451022.637039|10.662
MisV0143 = tass_id 12614671 ??
Julian Date|I-band
-----------------------+------
2450995.712569|12.265
2450696.618429| 12.03
2450717.5613|12.046
MisV0144 = tass_id 11948558
Julian Date|I-band
-----------------------+------
2451027.62478|10.552
2450927.896509|10.241
2450939.86353| 10.2
2450951.827909|10.217
2450952.828389|10.123
2450928.891979|10.166
2450995.712689|10.235
2450967.789979|10.081
2451006.76303|12.527
2451022.636469|10.463
MisV0161 = tass_id 11948325 ?
Julian Date|I-band
-----------------------+------
2450967.78908|12.077
2450952.82749|11.335
2450939.862639|11.534
2450928.891079|11.006
2450927.89563|11.247
2450951.827|11.846
MisV0162 = tass_id 11948958 ?
Julian Date|I-band
-----------------------+------
2450927.898039|11.151
2450952.829909|10.976
2450928.8936|10.938
2450939.86506|11.012
2450951.82944|10.962
2450995.714219|11.832
2450967.791569| 11.33
2450640.68764|12.122
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