Submitting Variables to VSX
We encourage individual submission of new variables to
the Variable Star Index (VSX). These can be single stars
that you have discovered through your own observations or
through data-mining; batches of stars, such as from a publication
that is not already included in VSX; or changes/modifications/comments
on existing VSX stars.
As opposed to asteroid discovery, you will get little or no
credit for discovering a new variable star. It is pure science
and the willingness to contribute to the community. A new
variable will typically have some assigned name (from an existing
catalog like GSC, 2MASS, etc.), and sometime later, it may
also have an assigned GCVS name (this can take years). Your
name will not be attached, except as a reference. You do not
get to name your discovery. There are rare occasions when an
unusual object garners attention, and an informal discoverer's name
gets attached: McNeil's Object, Sakurai's Object, Barnard's Star,
etc. Don't count on it, though!
Adding stars to VSX helps the community. When studying a particular
star, observers typically use one or more neighboring stars as
comparison stars. By letting the community know about every
variable, observers can search VSX when selecting their comparison
stars and know that they are not selecting a known variable.
Adding variables to VSX also broadens the database of variables,
giving more selection to researchers who are interested in a
particular class, period, location for their studies. You may
think that adding only one star is not important, but it is like
voting - thousands of people adding one star apiece can be
extremely important, and your particular star might be that
really unusual one that everyone wants to study.
So, let's get into the details. While the discussion below
is geared towards someone submitting original observations
leading to the discovery of a variable, you can also do
data-mining of existing catalogs like ASAS and NSVS. Just
beware that there is a double standard: we are more critical
of data-mined submissions because we expect the submitter
to do some work, such as period analysis, rather than just
regurgitating information already available from a given
survey's site. Also, don't be too critical of objects already
contained within VSX: we have accepted complete lists of previously
published objects rather than applying criteria to each and every
object on those lists. New submissions are subject to more
strict quality control.
I. IS YOUR OBJECT VARIABLE?
To make it into VSX, the object must be proven variable. What
constitutes proof, though? Here are some basic guidelines. We
will bend the rules in unusual circumstances, but in general, if
you follow these guidelines you have a very good chance of having
your favorite object added to the system.
a. Variability must be determined
beyond a shadow of a doubt. If you submit few datapoints, you need
to justify your conclusion with supporting evidence: large variability
(include measurement errors), red color/mira typing using 2MASS, etc.
We strongly encourage
that you observe your object often and submit a true light curve
rather than a few discrepant measures. Submission of discoveries
from visual observations is discouraged, except for transient objects
like novae. If you are suspicious of visual variability, we recommend
joining the VSX Discussion Group
and asking questions or requesting confirmation.
b. Unfiltered observations are discouraged. There are many systematic
problems with unfiltered observations. If you must submit unfiltered
photometry, you need to check a plot of airmass for the observational
dataset so that you can see if your variation mimics or mirrors the
airmass change (a common problem). You should also check the color
of the object and of the comparison stars, if possible (Tycho B-V,
2MASS colors, something that helps you understand the color differences).
We may request more supporting evidence for unfiltered submissions.
Observing with at least two filters is highly useful for discovery
workou can often roughly classify a star if you have its color
and light curve shape.
c. For transient objects, such as novae, we strongly recommend that
you first submit your discovery to the IAU Central Bureau for Astronomical Telegrams.
That disseminates the information the fastest, and also is the
avenue for obtaining confirming observations of your object (CBAT
usually contacts the AAVSO for followup observations). You can
also announce your discovery on many of the alert maillists, such
as vsnet-alert and baavss-alert.
II. WHAT TESTS SHOULD I PERFORM BEFORE SUBMISSION OF A DISCOVERY?
a. First, you need highly accurate coordinates of your new object.
There are many software packages that can do this for you, but
you should get a position with no worse than an arcsec or two of
b. Minor planets are the vermin of the sky. They get into many
images, and when near stationary points, can be very slow moving.
Check to see if one of these might be your new star at the
SN Candidate Minor Planet Checker.
We also highly recommend that your observations be made over several
days so that you can look for even small motion.
c. Check to see if this is already a known variable. The best
place to start is VSX itself. You should do an area search, as an
exact coordinate match is unlikely, and some reported variables
had large error in their discovery report. Other sources to
search include SIMBAD and
(VizieR will also give you cross-identifications and photometry
from existing catalogs, useful information to submit with your
d. If you are observing unfiltered, don't compare your results
against any of the photographic surveys (DSS, POSS, etc.) to
demonstrate "variability". Many red objects will appear brighter
on your images than on the archival plates; this can often be
many magnitudes of difference.
e. Look carefully at your images. There are many defects that
can lead to false variability. We've already mentioned airmass
effects, but there are ghost images of bright stars, scattered
light, hot/cold pixels that migrate through images during time
series, etc. Think of any way that a problem could effect your
data and guard against it before assuming variability. If you
are uncertain, ask the experts on one of the maillists we've
mentioned, or aavso-photometry, etc.
III. SUBMITTING YOUR RESULTS TO VSX
a. You need accurate coordinates. Anything with more than an
arcsec of error is discouraged. It is easy to get subarcsec
errors with the modern astrometric reference catalogs now
available. If the object appears on some common catalog, you
will be asked for that cross-id. Coordinates should come from
an astrometric catalog unless you know that your coordinates are better.
Some common examples of cross-identifications:
b. You need an estimate of the mean magnitude and of the amplitude,
or of minimum and maximum magnitude. If you have calibrated reference stars
in your image, use those to determine the zeropoint and the target
magnitude. Use catalogs like APASS, ASAS-3 (V-filtered), CMC14 or UCAC3
(through transformations) to get V magnitudes.
- GSC 01234-06789 (5 digits before and after the dash, use leading zeroes if necessary)
- 2MASS J11431012-5804040 (use a J before the coordinates)
- USNO-A2.0 0300-13671194
- USNO-B1.0 0319-0360318 (use a dash between USNO and the catalog version, it is part of the acronym)
- GSC2.3 S111210165373
- UCAC4 810-003941
You can also use USNO-A2.0, USNO-B1.0, GSC2.3, etc. if the star is too
faint and not present in the other surveys, but you should indicate the
type of magnitude and its source.
This will likely be modified by some observer in the future, but
is needed as a guideline for all observers and query tools.
c. Submit supporting evidence. At minimum, we request a
plot of the photometry with time on the horizontal axis and
magnitude on the vertical axis. If you have sufficient information
to analyze the light curve, determining period and classifying the star,
then you should also submit a phase plot. You can also include the actual
data in a tabular form as it may clarify suspicious light curves or help
in a better determination of type and/or period later on. Submitting the
data in tabular form only will slow down the acceptance process
as someone then has to plot that data. Do not submit the actual
data under the assumption that this Web site will archive that data, as
VSX is not the AAVSO International Database. We do not guarantee
that any submitted data will be retained.
d. Most 14th magnitude stars are easily identifiable on the DSS with
good coordinates. However, for crowded fields, or very faint stars,
or stars that do not appear in one of the major catalogs like NOMAD,
you should submit a finding chart. The rule of thumb is that if there
is any chance for confusion, identify. You want people to be able to
find this new variable! These finding charts should be in
jpeg or gif and reasonably small; north and east marked, and some
indication of scale (verbal is ok).
IV. NEW VARIABLES/SUBMISSION FROM DATA MINING
In general, the data submitted to VSX for new variables found in (public)
survey data should be as complete as possible: the position, variability
type, and maximum and minimum magnitude should always be given. For
periodic variables also the period and epoch (time of minimum for
eclipsers, and of maximum for pulsating and eruptive variables) are
a. Always give the id of the object from the survey, e.g. NSVS 123456 or
b. The positions given by surveys like NSVS and ASAS3 are not very precise
and may have errors of 10" and more. If it is possible to unambiguously
link the object to one from an astrometric catalog, give the id from that
catalog and use its position. Depending on their brightness, stars closer than 60"
from each other may be
blended and measure as one object in some of the surveys, try to choose the most
probable identification based on colors or magnitudes.
c. Do not attach the light curves provided by the NSVS
or the ASAS3 web site, nor the NSVS or ASAS3 data
themselves. These are easily available from within VSX. Instead provide
phase plots (for periodic variables) or combine light curves from several
surveys into a single plot, making sure data from different surveys are
distinguishable. When two or more synonyms are present in the NSVS
database, combine these on a single plot as well, preferably also with
different symbols and/or colors. Data from other surveys for which there
is no link-out from VSX should be attached or an url should be provided.
d. Some general remarks on the use of data from particular surveys:
V. NEW VARIABLES/SUBMISSION FROM THE LITERATURE
- The date given by NSVS is MJD-50000 = JD-2450000.5. VSX expects a JD for the epoch, so add 2450000.5 to the NSVS date (and make the heliocentric correction)
- Use mask 6420 for NSVS data.
- In general, do not use ASAS data of category D.
- Submissions based only on Tycho photometric data are not acceptable.
a. A number of variable star catalogs has been imported into VSX. However a
large number of variables have been described in the literature, which
have not been assigned a GCVS name and have not been incorporated into
VSX. For other variables up-to-date information exists in the literature
(e.g. corrections of GCVS or survey data) but it has not yet been entered
into VSX. Your help to make VSX more complete and up-to-date is also
b. Provide all data found in the paper. Use the position as given the paper,
or provide a better position (from an astrometric catalog) based on the id
given in the
paper. Information which cannot readily be placed into the standard VSX
fields, should be added as a comment. E.g.: magnitude at secondary
minimum for an eclipsing binary, epoch of secondary minimum for an
eccentric eclipser, etc.
c. Provide the bibcode of the publication and the link to the ADS abstract
page (http://adsabs.harvard.edu/abs/...) when it
exists. For preprints published on astro-ph, give the url of the abstract
page as well (e.g. http://arxiv.org/abs/astro-ph/0102987). When a bibcode
or astro-ph entry does not exist, give the url of the online publication
whenever possible. When a publication cannot be accessed online,
provide a scanned copy, so that the moderators can verify your submission.
Notes in email discussion groups such as vsnet-alert,
AAVSO-discussion, etc. are acceptable as references when they provide
enough information to decide that the object is a variable (in principle the same
rules as in sections I and II are valid here).
d. If there are more than 20 or so new objects or revisions available
electronically in tabular form from a single publication, mention this on
vsx-dis. Often these can be more easily imported into VSX, rather than be
VI. THE VSX PROCESS
Once you've submitted a new star for inclusion in VSX, the
request is sent to a group of volunteer "moderators." These
folk are experts in variable stars, usually having looked at
thousands of light curves and often long-time observers themselves.
One of more of the moderators will look at your submission. If
you have been diligent and have submitted an obvious candidate,
it will often be approved within a very short time (up to a few days),
depending on the workload.
There will be submissions where the moderator thinks insufficient
or incorrect information has been submitted. He or she will then
usually contact the submitter, asking for clarification. Do not
consider this as confrontation or lack of respect; these people
are truly trying to help. They may offer suggestions as to how
to submit later discoveries to make their process easier in the
Submissions that haven't yet been accepted because modifications were
required, will be deleted by the system after two months (60 days).
Also, do not be angry or discouraged if your submission is rejected.
The moderators will give you their reasoning for the rejection.
Read it carefully! You will get rejection often in life, and
astronomy is no different. Most professionals submit dozens
of proposals during their career with the majority being
rejected by their peers. Learn from the comments and try again!
At any time, the moderators may invoke their right to revise or otherwise
update any submission made to VSX for clarity, consistency, or
convention, whenever they believe the modification can be made
without adversely affecting the integrity of the submission. Typically,
you will be informed of any changes made by the moderators.
VII. OTHER LINKS
Note that these comments are geared towards submission to VSX.
VSX submission does not preclude sending your data analysis to
some other additional source, perhaps as a formal paper for
publication. We do not retain any kind of right to your data,
though we expect to publish a paper series that includes all
new discoveries with their discoverer acknowledged. There
are many journals that accept variable star research, and
we recommend that you look at them all carefully. The ones
we've found most useful are:
A good basic journal. Electronic only. Now refereed.
Peremennye Zvezdy (http://www.astronet.ru/db/varstars/)
Run by the GCVS folks. Electronic only. Refereed. The supplement contains
primarily observational results and matches most discovery projects.
Run by the IAU Commission 27 and 42, this is a fully refereed journal.
Electronic and hardcopy. Harder to get papers published here; usually
require full analysis.
Run by the AAVSO; fully refereed and both electronic and hardcopy. There is
a page charge for non-members.
Primarily for members of the BAA. Nice journal published 6 times per year.
No electronic version.
This fully refereed, professional journal will accept quality articles
from amateurs. Page charges.
Many other professional journals accept variable-star articles,
but the ones listed above are the most common. Good luck!