This is the main page for work on Cepheid Variables from the Small Magellanic Cloud.
Please note that there are subpages; one for each of Leavitt's Cepheids that we are working on. We have, within the appropriate subpage, FINDER FIELDS from either AAVSO or SIMBAD for the five stars. [Dec. 1, 2011]
[June 27, 2013] New light curves for BZ Tuc, including ASAS J004045-7343.00, were placed in the BZ Tuc subpage within Miss Leavitt's Cepheids.
[June 26, 2013] Finally re-engage with HV 1492.with new ppt for HV 1492 light curve and work with APASS and AFTERGLOW. See subpage below
[Dec. 29, 2012] Re-engage Leavitt's stars starting with HV 1492.
[May 26, 2012] Uploaded ppt document with light curves related to our search for "new" variables within the SMC-in this case near BZ Tuc. See ppt below.
[April 28, 2012] A talk on Leavitt's Cepheids was presented to CS-AAPT today. It is attached below as a ppt. Substantial progress has been made on collecting images and using AFTERGLOW to produce light curves four about a dozen of Leavitt's Cepheids. This progress has not found its way into this document. In mid-June, 2012, substantial content will be placed in the web site.
[Feb. 5, 2012] We are preparing maps from wider field PROMPT2 images of our HV Cepheids. Some of the stars are near enough to each other that more than one may appear in the PROMPT4/5 images of field 10' X 10'. The Leavitt Cepheids that we are working with separate into two regions, one with six Cepheids and five reference stars between -73 and -74 degrees south latitude and a second clumping [Latitude ~-72 to -73 degrees, of seven Cepheids and [so far found] only one AAVSO reference stars. Two preliminary mappings are in the files below. My students have also made many light curves and we are working to put them into a format suitable for uploading to this web site. My Physics 22 students have produced light curves for HV 822, 823 and 1351, mostly in the V filters. The Astronomy class is visiting all of the Cephieds for which we have decent images: HV 818, 821, 822, 823, 824, 1355, 1351, 1425, 1492, 1610 and 1645. For some of these we have more than one filter to use. We plan to upload these light curves and associated analysis of the images over the next several weeks. [note 4-28: This has not yet occurred.]
[January 18, 2012] We have finally figured out a bit how to obtain Finder and Reference Star charts from AAVSO!
[1-18-2012] We have uploaded a handful of SkyNet images of HV 822 to this site. These will be used on Saturday, Jan. 21 for the Miss Leavitt's Stars workshop.
[1-17-2012] A major breakthrough was achieved by discoverying how to find AAVSO finder charts for some of theese variables. The procedure was discovered by Elizabeth Ramseyer as she prepared for the upcoming Miss Leavitt's Stars workshop. The trick is to use VSX search and then get the ASAS [All Sky Automated Survey] designation of the variable. Then plug the ASAS id into AAVSO finder charts. None of the aliases for the HV stars that SIMBAD provides works for obtaining AAVSO chatrts as far as I can tell. SIMBAD does not provide ASAS ids? So now, for at least some of these stars, we can produces light curves with proper magnitudes. Work in progress at this point.
[1-14-2012] Produced and uploaded [see below] ppt for the S@Y January, 2012 Workshop: "Miss Leavitt's Stars"
[Dec. 28, 2011] Added ppt of HV 1425 with light curve over ~2.5 periods and with folded light curve. See its subpage below.
[Dec. 27, 2011] Added ppt of HV 822 light curve, ~5 days of ~16 day period, with discussion of project. See its subpage below.
[Dec. 6, 2011] We have our first nearly complete light curve for one of these Cepheid; HV 1492. See its subpage to view the light curve.
Four images from the PROMPT telescopes are shown below with some explanation given.
[11-27-2011] Observation requests have been made for two Cepheids in the SMC. One is HV 821 or BZ Tuc for which there is an AAVSO finder chart [success-see below**]. The other is for HV 822, for which I have yet to find such a chart. I believe that both HV 821* and HV 822 are from Leavitt's 1912 list of Cepheids.
**We have success with BZ Tuc! This luminous, long-period Cepheid is easily imaged with PROMPT 4 at 80s exposure. An image of this star is attached below as well as a comparison with the AAVSO chart. We have a long-term [140 day] image request every two days with SkyNet. [Update 12-19-2011: We have 56 images spanning 11/30-12/19/2011] Our goal is to obtain a good light curve and to involve students in the project.
Here is a url of Leavitt's 1912 list [Harvard Circular 173-25 Cepheids in SMC]: http://articles.adsabs.harvard.edu/full/1912HarCi.173....1L
Here is information on the article:
Title: Periods of 25 Variable Stars in the Small Magellanic Cloud.
Authors: Leavitt, H. S. & Pickering, E. C.
Journal: Harvard College Observatory Circular, vol. 173, pp.1-3
Bibliographic Code: 1912HarCi.173....1L
*A url from SIMBAD for HV 821 and its aliases; for example the U of Washington designation OGLE-CEP-417. The star is aka BZ Tuc. This url also gives a 3.4' X 3.4' fov. [OGLE-Optical Gravitational Lensing Experiment?]
http://cdsweb.u-strasbg.fr/cgi-bin/bibobj?2004A%26A...415..521S&HV+821