How to report new variable star discoveries
What do I do when I discover a new variable star?
We get that question a lot at AAVSO headquarters, and it deserves a detailed answer. It’s always exciting to discover a new variable star on your CCD frames, or from your nightly observations. Although discoveries of novae and supernovae often get more coverage, the discovery of less prominent variables can also have benefits for scientific research. Many thousands of variable stars are known to exist, but it’s likely that there are many millions more waiting to be discovered from the collected data archives of the amateur and professional observing community. So what should one do in the happy event that you discover what you think is a new variable star?
Check the catalogs
The very first step of course is to verify that it is indeed new, that it hasn’t been discovered as a variable by some other observer or survey. The first place to look is the AAVSO’s International Variable Star Index, VSX. This is the AAVSO community’s online repository of known variable stars, collected by the community from a number of different sources. The General Catalogue of Variable Stars is included, but many tens of thousands more variables are also included from a number of different sources. It’s a good bet that if a variable star is known and being actively observed, it’s in VSX. When you go to VSX, you should have a good astrometric solution for your CCD images, and know the position of the variable to within an arcminute at least.
As a secondary source, you can also double check several other online catalogs. Doing so might be useful if the star is present in another star catalog (such as the Guide Star Catalog, or 2MASS), but might not be known as a variable. This is especially useful for checking to see if the object is a nova or large amplitude star like a Mira. If it’s present in another catalog in a similar bandpass but with a much fainter magnitude, that lends weight to the possibility that it is indeed variable. You can search any number of catalogs using VizieR.
Another good practice is to make sure it’s not a solar system object! The solar system is full of asteroids, many of which can easily reach the brightness range available to amateur telescopes. You can search for possible solar system objects if you know the postion and the time of observation to good precision by going to the Minor Planet Center’sNEO Checker.
Check your data
Yet another check is to make sure there are no problems with the image itself. Some image defects like cosmic ray hits should be obvious as such — they’ll often have a jagged or blocky appearance in contrast to round star images on the frame. Bright moonlight or terrestrial light sources can also introduce ghost images or glints on your images. More subtle effects can sometimes occur. One example is residual charge: if you take an image that saturates a bright star, some charge may be left over at the position of the saturated object on several subsequent frames. The result will look like a fading star on subsequent frames. You should have a good feel for what your data say, and more importantly what they don’t say!
One last caveat is beware unfiltered observations! Many observers have had variable star “discoveries” turned into false alarms by making unfiltered observations with CCD cameras. Many different types of variables are red in color, and will have red magnitudes far brighter than the V or visual magnitudes reported in many catalogs. CCD camera systems have much stronger response to red light, and so unfiltered observations of red objects will make them seem much brighter when compared to a bluer field or comparison star. Be extremely careful when assessing variability based on unfiltered data; a good rule to follow is that unfiltered photometry is only useful for observing objects that aren’t red (i.e. have B-V < +0.7 or so).
Is it a nova or supernova?
If you think you’ve discovered a nova or supernova, the first place to report it is the International Astronomical Union’s Central Bureau for Astronomical Telegrams — follow the instructions on that page to make your report. This will ensure that your discovery will reach the largest number of people as soon as possible, and will also make it easier for other observers to confirm your discovery.
If your object is confirmed as a Galactic nova or bright extragalactic supernova, it will be added to the AAVSO’s database of objects in short order, but we require that it be confirmed by the IAUC as a nova or supernova before announcing it as such. In rare circumstances we will announce objects that have been submitted to us first if they are exhibiting interesting behavior that requires rapid announcement. However, it is strongly preferred that observers begin the process of reporting novae and supernovae with CBAT first.
Submitting to VSX
The AAVSO International Variable Star Index (VSX) was designed from the beginning to be an easy and straightforward tool for observers to search for known variable stars as well as to submit new variable star discoveries. You’ll need to do a few things in order to submit your star to VSX:
- You need to register for VSX
- You need to read the submission guidelines for VSX
- You need to know the position of your variable to an accuracy of a few arcseconds (at least), either by doing your own astrometry, or by identifying the object from an existing astrometric catalog (e.g. USNO)
- You need to know if the object appears in any other photometric or astrometric catalogs (e.g. Tycho, Guide Star Catalog, 2MASS, USNO-A or -B, or others)
- 你需要知道是否这个目标出现在其他的照相或者天体测量星表中（比如Tycho, Guide Star Catalog, 2MASS, USNO-A or -B或者其他的星表）
- You need to create a light curve of your data clearly showing the variability (for example, an X-Y plot made with Excel or any other spreadsheet or plotting program)
Once you’ve registered for VSX and logged in, you can then go to the “Submit” page, and follow the instructions on either the “New Star Form” or “New Star Wizard” links. With these tools, you can submit information about your variable to VSX moderators. These volunteers will look over your submission and determine whether your object is (a) correctly identified, (b) is variable, and (c) is previously unknown. If so, you will be notified that your submission was approved, and your object will appear in VSX. You’ll receive similar notifications if your submission is rejected, or if the moderators require more information to properly assess your submission.
Note that for those of you who are planning on writing a paper on your observations and would like to keep your data confidential, you may keep the supporting observations private, but the star’s identity will be made public as soon as you submit it to VSX. We encourage you to submit your objects as soon as you discover them, but please be aware that the community will at least be aware that your variable star exists as soon as you submit it to VSX, even if they can’t see your data.
Publish your results
All observers should be proud of the work that they do in discovering new observations, and an important part of the scientific work of variable star observing is sharing your observations with the community. One aspect of this is reporting your observations to the AAVSO, and you can do this as soon as your star is approved and entered into VSX. Another important aspect of variable star observing is publication — sharing your work in a formal way with the astronomical community through publication in a research journal. There are a number of journals that astronomical researchers use to learn about new discoveries, and the AAVSO has its own journal for variable star research — the Journal of the AAVSO.
所有的观测者都应该为所进行的发现而感到骄傲，并且向大众分享有关变星的部分科学工作也是非常重要的贡献。为做到这些，你可以报告你的观测数据给AAVSO，当然也可以在一些比较正式的天文机构杂志中发表论文来公布你的研究。有大量的杂志便于天文研究者去学习有关新发现，AAVSO也有自己的有关变星研究的杂志—the Journal of the AAVSO.
If you’ve discovered a new variable, you can write a paper about your discovery observations either before or after you submit to VSX. Purely observational papers are acceptable, and you do not need to be an astrophysicist in order to create a paper of value to the community. For example, you could easily create a paper detailing the circumstances of your discovery, your observing procedure, your observations and their analysis, and the results of your data analysis. Often, such a paper contains all the information another researcher would need to duplicate your results, and if need be to either derive important physical information about the star or to determine what future observations are needed to obtain such physical information.
If you have not written a paper before, you should read through the materials from the AAVSO’s Publication Workshop held during the 95th Spring Meeting in 2006. The presentations and other workshop materials are available here. When you submit your paper to the Journal of the AAVSO, it will be read by the editor, and if accepted for consideration it will then be sent to a referee who will make a recommendation as to whether it should be published. Again, your paper does not need to be comprehensive, but it should be as complete as you can make it given the data that you have.
如果你以前没有写过文章，最好先浏览一下来自于2006年第95届春季大会所举办的 AAVSO’S Publicacion Workshop 的一些材料。一些与会展示材料和其他的研讨会材料点击这里。当你提交你的文章给JOURNAL of the AAVSO时，编辑会进行审核，如果被采纳，将会送往审查人（专业文章鉴定专家)做一个推荐看是否予以出版。请记住，你的文章无需全面综合，但必须详尽的包含你所有的数据。
If you are interested in writing a paper on your discovery, we encourage you to read recent articles in the Journal of the AAVSO. If you’re not yet familiar with variable stars and their classifications, we encourage you to learn more about the subject. Two good introductory texts are Percy’s “Understanding Variable Stars”, and Sterken & Jaschek’s “Light Curves of Variable Stars”.
如果你对写有关发现的文章感兴趣，我们建议你读一下近期的文章。如果你对于变星和他们的种类（分类）还不清楚，我们建议你多学些有关这方面的知识。有两个比较好的文章推荐给你Percy’s “Understanding Variable Stars理解变星”, and Sterken & Jaschek’s “Light Curves of Variable Stars变星的光变曲线”.
For more information
The AAVSO community is very diverse, and there are many people who are interested in variable stars and enthusiastic about helping new members and observers learn more about variable stars and doing variable star research. There are a number of community resources you can take advantage of if you feel you need more information:
- The AAVSO Data Mining Section — researchers who mine existing data sources to obtain new variable stars and variable star data
- aavso-discussion — our online discussion group for all conversations relating to the AAVSO and variable stars
- aavso-photometry — our online discussion group for topics specifically related to photometry
- AAVSO headquarters (note that it may take some time before one of our limited number of staff members can respond to your request)