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\IBVShead{4773}{23 September 1999}

\IBVStitle{LOST VARIABLES ON NANTUCKET PLATES}

\IBVSauth{N.N. Samus$^{1,2}$, L. Haythe$^{3,2}$, S. Hornstein$^{4,2}$, L.J. Jisonna Jr.$^{5,2}$, E. Lu$^{6,2}$}

\IBVSinst{Institute of Astronomy, Russian Academy of Sciences,
48, Pyatnitskaya Str., Moscow 109017, Russia \indent [samus@sai.msu.su]} %email


\IBVSinst{Maria Mitchell Observatory, 3, Vestal Str., Nantucket, MA 02554, USA}

\IBVSinst{American School in London, London, UK [moon53186@aol.com]} %email


\IBVSinst{Virginia Polytechnical Institute and State University,
315 Miles Hall, Blacksburg, VA 24060, USA\\ \indent [shornste@vt.edu]} %email


\IBVSinst{University of Arizona, Tucson, AZ 85721, USA [ljj@u.arizona.edu]} %email


\IBVSinst{Wesleyan University, Box 4792, 222 Church Str.,
Middletown, CT 06459, USA [elu@wesleyan.edu]} %email


\IBVSabs{For 7 ``lost'' Harvard variables recovered on Nantucket plates,}
\IBVSabs{we present accurate coordinates, types, light elements.}
\IBVSabs{The case of the ``lost'' Cepheid IU Aql is discussed.}

\IBVSkey{variable stars; coordinates}

\begintext

For the reasons discussed by Hazen and Samus (1999), it is important to
recover Harvard variables lacking finding charts. This problem can be
most effectively solved using the Harvard plate collection, where many
plates still hold ink marks left by the discoverers. However, much can be
done using plate collections of other observatories. In particular, the
plate collection of the Maria Mitchell Observatory (MMO), containing especially many plates of the Scutum cloud, can be used with success to recover ``lost''
Harvard variables in this part of the sky.

In 1999 we have successfully recovered 7 ``lost'' Harvard
variable stars on Nantucket plates. The main results are
presented in Tables~1 and 2. The columns of Table  1 contain: GCVS name; preliminary Harvard designation (HV -- Harvard Variable); GSC number (if available); the star's right ascension and declination (equinox 2000.0); source of coordinates (A2.0 means the US Naval Observatory A2.0 catalog, Monet
et al.\ 1998; DSS means coordinates measured by us on a DSS image, relative
to several reference stars with coordinates from the USNO A2.0 catalog).
The columns of Table 2 contain: GCVS name; the star's type found in our study; light elements (epoch and period) if they could be derived from our Nantucket and Moscow data (epochs refer to minimum light for eclipsing variables
and to maximum light for other types; for Algols, the elements are
heliocentric).

We would like to discuss the case of one more star, the ``lost'' Cepheid IU Aql, in greater detail. It was discovered by Walton (1927) as varying between 13\fmm7 and 15\fmm2 on Nantucket plates. Walton writes that, at the MMO, 22 plates of the M~11 region were taken in 1918--1926, 16 of them showing ``stars of magnitude 15.5 or fainter'', obviously too optimistic an opinion about
old Nantucket plates. Harwood (1931) classified the star as a possible Cepheid, with light elements 
$${\rm Max = JD}\ 2415661+22\day\times E.$$

Near the position given by Walton, there is only one star bright enough, namely GSC 5129.00219 (19\hr14\mm33\fsec53, $-0\deg56\arcm51\farcs6$,
2000.0). The only published finding chart (Bateson et al.\ 1981) is not sufficiently detailed but does not contradict the above GSC identification. However, this GSC star is definitely not a Cepheid and probably does not vary at all according to modern photoelectric and CCD data (Berdnikov 1999).

\begin{table}[h]
\begin{center}
\caption{Identifications and Coordinates}
\begin{tabular}{llllll}
\hline
Name&HV&GSC&$\alpha_{2000.0}$&$\delta_{2000.0}$&Source\\
\hline
BC Sgr&3116&5414.00438&18\hr59\mm32\fsec29&--11\deg58\arcm19\farcs4&GSC \\
BY Sgr&3654&          &19 11 15.18&--13 30 20.9&A2.0\\
CU Sgr&3125&          &19 06 33.39&--12 16 28.1&A2.0\\
UW Sct&3643&5710.00841&18 56 33.16&--10 32 59.1&GSC \\
ZZ Sct&3821&          &18 44 37.74&--10 12 50.1&A2.0\\
AE Sct&3826&          &18 47 10.93&--07 43 54.6&A2.0\\
BC Sct&3838&          &18 56 05.4 &--07 49 46  &DSS \\
\hline
\end{tabular}
\end{center}
\end{table}

\begin{table}[h]
\begin{center}
\caption{Types and Light Elements}
\begin{tabular}{llll}
\hline
Name&Type&Epoch, JD&Period\\
    &    &24\dots\\
\hline
BC Sgr&M: &44490    &200\day \\
BY Sgr&SR:&         &         \\
CU Sgr&SR:&         &$\sim1$ yr?   \\
UW Sct&LB &48151    &         \\
ZZ Sct&EA &47739.703&2\fday199127 \\
AE Sct&EA &35246.779&4\fday664022 \\
BC Sct&M  &46662    &254\fday30   \\
\hline
\end{tabular}
\end{center}
\end{table}

\leftline{\it Notes on individual stars}

\smallskip

{\bf BC Sgr} The provisional elements in Table~2 are based on 13 maxima
after JD 2439000.

{\bf ZZ Sct} Elements have been slightly modified from those published
by Delhaye (1948) taking into account timings of 14 fadings on
Moscow plates and one, comparatively recent, fading on Nantucket plates.

{\bf AE Sct} We have found the star faint on 23 plates (JD 2435246--2448422);
these fadings are in poor agreement with the light elements from Oosterhoff
(1943). Our new elements (see Table~2) give $O-C=-0\fday376$ for Oosterhoff's
epoch 2427884.521, so the period has probably really changed.

{\bf BC Sct} According to the discoverer, Cannon (1924), the following
star in a close pair varies. The star found variable on MMO plates is
definitely a pair in the DSS. Its following component, not contained in
the USNO A1.0/2.0 catalog, is red and comparatively faint on POSS prints,
whereas it is brighter than the preceding component in the DSS. The epoch
of the DSS plate (JD 2446668) nearly coincides with the brightest maximum
observed by us (JD 2446662).

\newpage

The MMO possesses a copy of a PhD dissertation by Marjorie Williams (1941)
containing some unpublished results of probably the last study of
IU Aql on Nantucket plates. A photographic finding chart in the
dissertation clearly identifies IU Aql with the star now known as
GSC 5129.00219. No individual measurements are given for the star,
and the conclusion is the following:

``{\bf IU Aql.} At first this star was thought to have a period of less
than one day, and later was thought to be a Cepheid with a period of about 22 days. Only 87 observations were made in the present study, and it is felt that they are not very reliable, as the star was usually near the edge of the plates
and the images were diffuse. Not enough observations in one day were obtained
to tell whether it is a cluster-type or a typical Cepheid.''

We have located Dr.~Williams's working notebooks at the MMO. Most estimates
show IU Aql fainter than 14\mm; Williams estimated it brighter only on 8 plates. We have reexamined these 8 plates and, at least for 7 of them, could not reliably confirm the maximum. We conclude that the MMO plates studied by
Williams show few maxima, if any, and do not definitely confirm variability.
Harwood (1931) must have studied IU Aql on Harvard, not MMO, plates because
her light elements give the initial maximum not represented in the MMO plate collection, and IU Aql is not mentioned in M. Harwood's MMO notebooks. Either
the actual variable was lost soon after Harwood's study, or it ceased
variations as early as in the 1920ies. M. Walton Mayall's MMO notebook, found by Dr.~V.~Strelnitski, does not contain finding charts.

Thanks are due to Vladimir Strelnitski for his help and attention. This study was supported, in part, by grants from the National Science Foundation (AST 9820555) and from Russian Foundation for Basic Research (99-02-16333).

\references

Bateson, F.M. et al.\ 1981, Charts for Southern Variables, Ser.\,13,
Chart 568

Berdnikov, L.N. 1999, Private communication

Cannon, A.J. 1924, Harvard Obs.\ Circ., No.\,265

Delhaye, J. 1948, Bull.\ Astron.\ Inst.\ Netherl., {\bf 10}, 415

Harwood, M. 1931, Harvard Obs. Bull., No.\,880

Hazen, M.L., \& Samus, N. 1999, IBVS, No.\,4665

Monet, D., Bird, A., Canzian, B. et al.\ 1998, USNO A V2.0. A Catalog of
Astrometric Standards, US Naval Observatory (11 CD-ROMs)

Oosterhoff, P.Th.\ 1943, Bull.\ Astron.\ Inst.\ Netherl., {\bf 6}, 399

Walton, M.L. 1927, Popular Astron., {\bf 35}, 25

Williams, M. 1941, An Investigation of the Cepheid Variable Stars in the
Scutum Cloud, PhD Dissertation, Univ.\ of Michigan, Ann Arbor

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