some rarely visited Be stars

some rarely visited Be stars

Postby Robin Leadbeater » Sat Aug 03, 2019 10:55 pm

I have started looking at some of the stars which have no spectra in BeSS or the spectra are very old. I am using the LHIRES 1200l/mm (R~5500) as they are quite faint for the 2400l/mm grating

Here are a couple of interesting ones so far

V415 Lac (Vmag 9.2) was last measured in 1995 ! The EW of the H alpha emission now is approximately half that in 1995
v415lac_20190802_1995.png
v415lac_20190802_1995.png (21.18 KiB) Viewed 3299 times


bd+61 2494 (Vmag 10.0) has no previous spectra in BeSS. The star itself currently shows no emission, but it is embedded in an HII region and the sky background shows H alpha
bd+612494_20190801_979_Leadbeater.png
bd+612494_20190801_979_Leadbeater.png (48.08 KiB) Viewed 3299 times


Cheers
Robin
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Re: some rarely visited Be stars

Postby Robin Leadbeater » Sun Aug 11, 2019 4:26 pm

A few more rarely visited Be stars

These are the first spectra in BeSS for EM* CDS 1367 , EM* CDS 1464 , EM* MWC 1063 (2 in emission and 1 in absorption)

tyc3995-1452-1_20190807_892_Leadbeater.png
tyc3995-1452-1_20190807_892_Leadbeater.png (23.66 KiB) Viewed 3252 times


BD+57 2678 has only been measured once before (at low resolution) in 2012. The spectrum looks the same

bd+572678_20190808_052_Leadbeater.png
bd+572678_20190808_052_Leadbeater.png (30.22 KiB) Viewed 3252 times


Robin
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Re: some rarely visited Be stars

Postby James Foster » Wed Aug 14, 2019 10:58 pm

Nice work Robin!

I was doing the same late last year (shot 15-25 Be stars with 2 or less observations, mostly south of -10 dec).
I need to place the 2400 l/mm grating back into the LhiresIII (dont have the 1200 l/mm grating), but i've had alot
of fun shooting summer objects from 3850-6800A with the 600 l/mm grating.

James
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Re: some rarely visited Be stars

Postby Christian Buil » Thu Aug 15, 2019 9:57 am

Excellent Robin and James !

Christian
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Re: some rarely visited Be stars

Postby Robin Leadbeater » Sun Aug 18, 2019 2:14 pm

A couple more from a gap in the weather last night

HD181367 has only one other spectrum from 2006. The H alpha intensity is now significantly lower (EW ~1/4 of what is was then)

hd181367_20190817_20060723.png
hd181367_20190817_20060723.png (24.51 KiB) Viewed 3106 times


HD181803 is unchanged from 2006. (There is also a low resolution spectrum from 2013 which has ~ the same H alpha EW) so this one is probably be long term stable.

hd181803_20190817_20060718.png
hd181803_20190817_20060718.png (27.46 KiB) Viewed 3106 times


Cheers
Robin
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http://www.threehillsobservatory.co.uk
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Re: some rarely visited Be stars

Postby Paolo Berardi » Mon Aug 19, 2019 5:48 pm

Dear Robin and all,

yesterday I observed the Be star HD 345122, intrigued by the Gaia alert reported on Aug 16 (AT 2019ntu). The star was found about 0.2 mag brighter than the "normal" status (I think this value triggered the alert).

This appears to be confirmed by the ASAS-SN Sky Patrol light curve, showing a gradual increase of brigthness in the last months (between g mag and V mag I saw here there is an offset of ~0.25). With a concurrent photometry, during the spectro session, I measured V mag 9.57. Simbad reports V 9.80.

Image

In the BeSS database there are only three low-res spectra now. In my R ~6000 spectrum the h-alpha emission line is double-peaked, about 180 Km/s between V and R peaks.

Image

The light from the star is heavily reddened by dust in the ISM. This is clear from the low-res spectra in the BeSS and from the strong interstellar band (DIB) 6614A in my spectrum. IRSA/IPAC service provides a total extinction E(B-V) = ~ 1.13 in that direction.

After a search on web, I found an interesting paper: Photometric Variability of the Be Star Population, Jonathan Labadie-Bartz et al.

HD 345122 is being studied here among stars that exhibit oubursts (four outbursts have been identified), so this could be a new event.

Paolo
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Re: some rarely visited Be stars

Postby Robin Leadbeater » Mon Aug 19, 2019 6:52 pm

An interesting find Paolo. That paper is a good advert for BeSS and all the work done by amateurs collecting spectra. With an estimated photometric outburst rate on average 1.7x per year HD345122 could be an interesting one to follow more frequently.

Robin
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Re: some rarely visited Be stars

Postby Robin Leadbeater » Tue Aug 20, 2019 10:42 am

Robin Leadbeater wrote:An interesting find Paolo. That paper is a good advert for BeSS and all the work done by amateurs collecting spectra. With an estimated photometric outburst rate on average 1.7x per year HD345122 could be an interesting one to follow more frequently.

Robin


And this connects neatly with the proposed TESS/BeSS campaign that Coralie Neiner has just announced on spectro-l. (HD345122 is on the list !) We should probably set up a new thread for this

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dear all,

The NASA space photometric mission TESS is observing all types of stars
in the sky, including Be stars. This is a good opportunity to perform
combined spectroscopic and photometric studies, which would help to
understand Be outbursts. TESS changes field of view (called sectors)
every 27 days, therefore we need to concentrate on Be stars that have
rapid outbursts.

Jonathan Labadie-Bartz has put a list of interesting TESS Be targets
together, which is available here:
https://docs.google.com/spreadsheets/d/ ... edit#gid=0

The following link tells you which sector TESS is observing at what time
(currently sector 15): https://tess.mit.edu/observations/#sched

It would be great if we could obtain 1 spectrum per night of each Be
target being observed by TESS (during the TESS observations). This means
we would observe the Be targets of one sector for 27 days, then move on
to the targets of the next sector for 27 days, and so on. Ideally what
we need is high-resolution spectra, at least Halpha and if possible full
echelle spectra, but lower resolution spectra are welcome too.

If you wish to participate to this project and you obtain data of the
TESS Be stars, please upload them in BeSS as usual.

Thanks!
Coralie Neiner
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Re: some rarely visited Be stars

Postby Paolo Berardi » Tue Aug 20, 2019 11:45 pm

Thanks Robin!

A lot of target in the TESS Be list...

I think I should have observed HD345122 between July 18 and Aug 15, when TESS was observing the sector 14. Now it is on sector 15. If I understand correctly, we should observe (up to Sept 11) all targets containing the number 15 in the sector field of Be_Star_table.

Paolo
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Re: some rarely visited Be stars

Postby Robin Leadbeater » Wed Aug 21, 2019 9:50 am

Hi Paolo,

I have started a new thread for the TESS monitoring programme and replied there
viewtopic.php?f=14&t=2382&p=13052

Cheers
Robin
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