hunting for UXORs among EA stars
Hi,
As leader of the YSO group at AAVSO, I am interested in running a campaign to try and find UX Orionis-type stars among the less well-known 'Algol' stars. UX Ori stars (UXORs) are young stars engaged in the formation of planetary systems and which show Algol-like falls due to obscuration by accreting planetesimals in the circumstellar disc. For this reason, certain stars (BO Cep for example) were once classed as Algol-type stars but have later turned out to be UXORs!
Since YSOs are strongly found in low galactic latitudes, the campaign would only search among those stars in, or close to, the plane of the milky way.
Anyone interested?
Hi, Mike,
Very interesting indeed.
In the course of the VSX revisions, I remember having reclassified some from E to UXOR. From the top of my head, KR Mus was one of them, classified as E by Hipparcos.
There are a lot that seem to be in need of a revision. BO Cep is still not classified as UXOR so I'll revise it tomorrow.
If you have a list of known UXORs that could be used to update VSX, it would be helpful.
Cheers,
Sebastian
Buenas tardes Sebastian!
(Sorry, no inverted ! on this keyboard)
I don't have a list to hand at the moment, but I know there aren't that many (yet). The GCVS page is no good, since the variable types there are all ISA, INSA and so on. Personally I was planning to start using some selected stars, having a look for IR excess and then going to ASAS with the likely candidates.
-from memory, some UXORs: BO, IL, SV, YZ Cep, MQ Cas, WW Vul, XX Sct (I think). Also, some stars classified as RCBs may be UXORs as well! I had today's variable on the home page, RZ Vul, as a possible, but in this case I don't think it is. Always good to look at though!
Folks,
Remember that considerable progress has been made on cleaning up RCB classifications. In case you aren't a member (yet!) of the R CrB forum, I call attention to our recent paper:
http://arxiv.org/abs/1211.2475
Cheers,
Doug
The non-Mira and low-galactic latitude non-RCBs in our Table 5 might be worth a scan for UXORs.
Cheers,
Doug
Mike, thanks for bringing those to my attention, I'll check them.
Doug, in fact, Patrick and I checked that list (I think there are still some left to check) and several miras, RV Tauris and UXORs came up from it.
The 4 UXORs candidates are TYC 7672-563-1, TYC 8999-807-1, ASAS J070615-1904.4 and 2MASS J16544896-4032517 and have been revised in VSX.
Cheers,
Sebastian
Hi Sebastian,
Glad to hear it! I am always wildly impressed by how quickly the VSX team makes use of new variable star information!
Cheers,
Doug
Folks,
It would be useful and instructive to compile a set of UXOR lightcurves in a single location. Does such a resource exist?
Cheers,
Doug
Mike,
i'm still not clear if you're proposing an observing campaign or a data mining campaign.
Bill
Hi, Mike:
You had written: "-from memory, some UXORs: BO, IL, SV, YZ Cep, MQ Cas, WW Vul, XX Sct (I think)"
I checked the literature and the surveys for data on those stars and revised their VSX entries. Only SV Cep and WW Vul were previously catalogued as UXORs.
I could confirm the UXOR nature of BO and IL Cep, MQ Cas and XX Sct but failed to do that for YZ Cep. More obervations needed.
I'll be adding some more on the days to come. So a VSX search by type will reveal the ones already confirmed in VSX.
Cheers,
Sebastian
Cheers Sebastian,
As I said, I was working from memory (in fact I was upbraided by John Greaves for including YZ Cep as an UXOR!) so, no hard feelings! Certainly the variations of YZ Cep make it look like UXOR. The jury is still out on RZ Psc, a most peculiar star, which I didn't mention.
What's different from the YSO campaign? Are there different targets? Is it just a matter of looking at light curves that are (slowly) accumulating for those stars?
Jim Roe