From jop at astro.columbia.edu Sun Mar 8 12:08:00 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 8 Mar 1998 12:08:00 -0500 (EST) Subject: (cba:news) MM Hya rises from its long sleep Message-ID: <199803081708.MAA18605@tristram.phys.columbia.edu> Dear CBAers, March 8, 1998. Last night Jonathan found MM Hya="Hya 1" (in Downes and Shara catalogue) at V=13.8. The star has an orbital period of 82.9 min, and is thus one of our favorite li'l short-period guys. However, no light curves have been obtained in outburst, ever. So we are pow'f'l motivated to cover the present outburst with long, tree-to-tree coverage. The outburst period is definitely long, possibly as long as 20 years - last known one occurred about when Jonathan was learning to finger-paint. And it's definitely a superoutburst. His light curve last night showed a classic superhump of 0.25 mag amplitude. The best fit period was 86+-3 min, but the observation was short and needs refinement over a much longer baseline. A quite nice paper on this star (and others) is by Misselt and Shafter 1995 (AJ 109, 1757). The Tololo run is over now, so we cast this out to the CBA world. The star is located at 2000 coords 9 14 14.0, -6 47 45. There's a chart at our website, also listed as PG 0911-066, its other name. We've been following it sporadically throughout the year to build baseline for an accurate Porb measurement. But this is outburst, quite a different matter. I dunno how long it will stay bright. But however long it stays, keep after it a bit longer to watch for echo outbursts. This is a definite winner. And equatorial too. Polish up that telescope and let 'er rip! Pay no attention to that rogue Moon which may be lurking nearby. The usual practice, unfiltered time-series photometry with respect to one of the two comparison stars on the chart, is fine. And if you measure the delta-mag between those two comparison stars, so much the better. Lemme know what you can get - I'll analyze the data as soon as it comes in and advise on the status of our period-finding. Quick update on other campaigns: T Pyx. Over. Enemy vanquished. HP Lib. Just getting started. Good morning target for all locations. AM CVn. Also near start. Good for pretty much all northerners. DI UMa. Gotta keep pushing it for another month. Working very well, but the star's frequent up and down excursions make it more difficult to splice together light curves at a similar luminosity state. We'll make it if the DI entrepeneurs keep the faith. You know who you are out there. RZ LMi. Basically the same story. DW UMa. Hold your fire. Too much other stuff in that part of the sky this year. AH Men. Getting wonderful data sets from Marc Bos. As long as he keeps doing it, all you other Southerners are off the hook! But he could use some help. Website at https://cbastro.org joe From jop at astro.columbia.edu Sun Mar 8 12:08:00 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 8 Mar 1998 12:08:00 -0500 (EST) Subject: (cba:news) MM Hya rises from its long sleep Message-ID: <199803081708.MAA18605@tristram.phys.columbia.edu> Dear CBAers, March 8, 1998. Last night Jonathan found MM Hya="Hya 1" (in Downes and Shara catalogue) at V=13.8. The star has an orbital period of 82.9 min, and is thus one of our favorite li'l short-period guys. However, no light curves have been obtained in outburst, ever. So we are pow'f'l motivated to cover the present outburst with long, tree-to-tree coverage. The outburst period is definitely long, possibly as long as 20 years - last known one occurred about when Jonathan was learning to finger-paint. And it's definitely a superoutburst. His light curve last night showed a classic superhump of 0.25 mag amplitude. The best fit period was 86+-3 min, but the observation was short and needs refinement over a much longer baseline. A quite nice paper on this star (and others) is by Misselt and Shafter 1995 (AJ 109, 1757). The Tololo run is over now, so we cast this out to the CBA world. The star is located at 2000 coords 9 14 14.0, -6 47 45. There's a chart at our website, also listed as PG 0911-066, its other name. We've been following it sporadically throughout the year to build baseline for an accurate Porb measurement. But this is outburst, quite a different matter. I dunno how long it will stay bright. But however long it stays, keep after it a bit longer to watch for echo outbursts. This is a definite winner. And equatorial too. Polish up that telescope and let 'er rip! Pay no attention to that rogue Moon which may be lurking nearby. The usual practice, unfiltered time-series photometry with respect to one of the two comparison stars on the chart, is fine. And if you measure the delta-mag between those two comparison stars, so much the better. Lemme know what you can get - I'll analyze the data as soon as it comes in and advise on the status of our period-finding. Quick update on other campaigns: T Pyx. Over. Enemy vanquished. HP Lib. Just getting started. Good morning target for all locations. AM CVn. Also near start. Good for pretty much all northerners. DI UMa. Gotta keep pushing it for another month. Working very well, but the star's frequent up and down excursions make it more difficult to splice together light curves at a similar luminosity state. We'll make it if the DI entrepeneurs keep the faith. You know who you are out there. RZ LMi. Basically the same story. DW UMa. Hold your fire. Too much other stuff in that part of the sky this year. AH Men. Getting wonderful data sets from Marc Bos. As long as he keeps doing it, all you other Southerners are off the hook! But he could use some help. Website at https://cbastro.org joe From jop at astro.columbia.edu Mon Mar 9 07:25:23 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 9 Mar 1998 07:25:23 -0500 (EST) Subject: (cba:news) more stars of march Message-ID: <199803091225.HAA19910@tristram.phys.columbia.edu> Dear CBAers, March 9, 1998. Got a few amendments to yesterday's message, mainly for australites. I spent a few hours studying the AH Men data for the whole season. I think the data are complete enough now to end for the year. All three signals (orbit, positive and negative superhumps) are pretty well delineated. So let's leave it till October. I didn't mention it before because I thought the star was too faint (though it's on the Most Wanted list), but after a few days of watching the wave in CP Pup's light curve, I now think the humps in this star can be observed by small telescopes. Very healthy humps most nights (not all) at P=90 min in this V=15.4 star. Go for it. I also think DI Cru, the star flagged by Diaz and Steiner (and Kato and Morel) and described below, is well worth a long campaign by smallscopers in the south. It's bright enough to survive much moon and cloud, and as a possible relative of V Sge is of great interest to us. Perfect time of year too, I reckon. But I hope you give MM Hya top priority. We've been waiting a long time for this sonofagun! Here's the DI Cru info... joe >DI Cru > > According to the recent article by Steiner and Diaz (PASP in press), >HD104994, now named DI Cru, shows peculiar characteristic common to the >peculiar "novalike" V Sge. The spectrum of DI Cru is WR, resembling that >of V Sge, the orbital period 7.46 hr (Niemela et al.). Being 10-th mag >object, this star should deserve a handy target for small telescopes. >(The only regret for me is that the star locates too south..). It would >be interesting to see whether the star shows long-term behavior similar to >that of V Sge. > Colleagues, I notice that a fine chart and deep photoelectric sequence exists for the region of DI Cru. It is in Astron. Astrophys. Suppl.(1973)12,365-380 by G. Lynga and S. Wramdemark. In area CB, HD 104994 is identified and measured as Star 11, V=10.93, B-V =-0.06, U-B =-0.84. The nearest star of somewhat similar brightness is Star 14 (V = 10.36, B-V = 1.22, U-B = 1.05) at (1950) 12:03:10 -61:50.9. Star 21 has V = 10.97, B-V = 1.00, U-B = 0.75. It is at (1950) 12:05:06, -62:10.8. HD 104994 is also on HDE chart 149, very close to the left edge and just south following HD 104901, a double star (d = 26"). Regards, /Mati /=====================================\ | MOREL ASTROGRAPHICS | | Stellar Data & Information Centre | | c/o M. Morel | | 6 Blakewell Road, | | Thornton NSW 2322 AUSTRALIA | | Tel./fax: (02) 4966 2078 | | 151d38'33" E, 32d46'47"S | | e-mail: morel at ozemail.com.au | \=====================================/ From jop at astro.columbia.edu Mon Mar 16 05:46:41 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 16 Mar 1998 05:46:41 -0500 (EST) Subject: (cba:news) Victory over DI UMa Message-ID: <199803161046.FAA01340@tristram.phys.columbia.edu> March 16, 1998. Dear CBAers, Is ours. We have the quiescent (orbital) period nailed down, and the superhumps during the two well-covered superoutbursts repeated with high accuracy. The normal outbursts are basically a washout - no periodic signals. This means that we can take DI UMa off our list, except we would still like to know when the outbursts occur - so *snapshot* magnitudes will be fine, but not time series. Which means we might be able to finish RZ LMi off before the season ends. This is the most excellent of our evening targets these days. (Of our *regulars* - rare erupters are a different story.) Speaking of which, I hope someone is watching MM Hya! Right after I sent out an alert on this star last week - OK actually it was about 4 d later - the weather turned steadily bad in Europe (I think) and Arizona (I know). Help, help, we're drowning in the vast seas of open space in the O-C diagram! A terrible fate indeed. For those of you getting started on CBA programs, AM CVn and HP Lib are excellent targets to start on, assuming you can get your clock good to 10 s or so. Or, if you want something even brighter, try RW Sex or UX UMa - bright and forgiving. For veterans of last year's EG Cnc wars, I have a paper almost ready for submission. Lemme know if you have extra data on this star. Snapshot magnitudes are also of extremely great interest, as the star's eruption characteristics are I'd say the strangest of all known dwarf novae. joe