HOYS @hoys.bsky.social · 20/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 345 - HOYS Citizen ScienceThis week we look again at a non-YSO variable. It is the Mira type star KS Cyg, which is situated in the MWSC3274 target region. We showed some V-band data of this source in week 116. In the above pl... 050
HOYS @hoys.bsky.social · 20/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 344 - HOYS Citizen ScienceThe last time we looked at the light curve of this object, was in week 26. This was pre having the HOYS website, when the posts where exclusively placed on the Facebook Group. The source is a backgrou... 040
HOYS @hoys.bsky.social · 20/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 343 - HOYS Citizen ScienceWe look at another 'simulation' plot this week :-) What if you had a forming protoplanet close to a young star and this planet accretes material? This means a large fraction of the volume around the ... 050
HOYS @hoys.bsky.social · 01/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 342 - HOYS Citizen ScienceWe have a look at some items related to spots on young stars this week. The properties (size and temperature) of these spots are determined from amplitudes in periodic light curves in various filters.... 030
HOYS @hoys.bsky.social · 01/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 341 - HOYS Citizen ScienceThis week we have look at the light curve of the young star Mayrit 789281. It is located in the sigma-Ori target region of HOYS. This field has very good coverage in the last 5yr. We show the long t... 030
HOYS @hoys.bsky.social · 01/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 340 - HOYS Citizen ScienceThe plot above looks like the usual spot induced periodic light curve of a young star. But it is not :-) . We show the light curve for the star BS Vel. It is actually a nearby star (distance 181pc) w... 030
HOYS @hoys.bsky.social · 01/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 339 - HOYS Citizen ScienceThis week we look at V608Mon, a T-Tauri star near the Cone Nebula in the target region NGC2264. The last time we looked at this source was in week 286, about one year ago. In images the object is sur... 030
HOYS @hoys.bsky.social · 01/08/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 338 - HOYS Citizen ScienceThis week we revisit the light curve for the star 2MASS J20522802+4403311. We looked at it about one year ago in week 282 and found it to be an Orion type variable. These are objects whose variations ... 010
HOYS @hoys.bsky.social · 27/06/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 337 - HOYS Citizen ScienceThis week we have a look at the HOYS data for the star RW Ori. It is in the well observed Sigma Ori target region of the project. towards the end of 2023 we had a look at this object during weeks 254 ... 051
HOYS @hoys.bsky.social · 20/06/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 336 - HOYS Citizen ScienceIf you’ve been following our updates, you’ll know we often talk about starspots on the surfaces of young stars. These spots are responsible for the periodic dips and rises we see in their light curves... 050
HOYS @hoys.bsky.social · 15/06/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 335 - HOYS Citizen ScienceThis week, we turn our attention once again to a familiar and intriguing object in our project: the young star GM Cep in the IC 1396A target field. We last reported on it back in Week 299, when the st... 150
HOYS @hoys.bsky.social · 09/06/2025We are back with our HOYS-LCO program for next Winter (2025/26). If you want to get your pupils involved apply now on the website: hoys.space/lco-project/ Please share this if you have any teacher contacts that might be interested. 🔭hoys.spaceLCO PROJECT - HOYS Citizen ScienceLCO PROJECT YEAR 6 Our project as a Global Sky Partner of Las Cumbres Observatory, this time for school teachers and their students. Join and gather data using these telescopes for the HOYS project... 120
HOYS @hoys.bsky.social · 06/06/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 334 - HOYS Citizen ScienceWe revisit the variable star V350Cep in NGC7129 this week - an old friend of the project. The last time we looked at it was about 6 months ago in week 309. The object is a suspected FU Ori outburstin... 050
HOYS @hoys.bsky.social · 30/05/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 333 - HOYS Citizen ScienceWe have not had a look at one of our "old friends" NSW284 for quite a while. The last time we looked at it was in week 257, about 1.5yr ago. This object was the first Be type outburst star we accident... 020
HOYS @hoys.bsky.social · 24/05/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 332 - HOYS Citizen Science"Not V2492Cyg again!" ... is what the regular reader of these posts might shout. I know! But this one is special, and a follow up on the post from week 316 in January. The plot is a screenshot from a ... 031
HOYS @hoys.bsky.social · 18/05/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 331 - HOYS Citizen ScienceWe have a look at a light curve from the Lambda-Ori target region this week. This field, which is centred on the cluster also known as Collinder 69, or MWSC 0580, is one of the lesser observed targets... 050
HOYS @hoys.bsky.social · 08/05/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 330 - HOYS Citizen ScienceThis weeks light curve does not look very interesting. But it is :-) We show the R and I-band data for the last two years for the star Cl* IC 348 LRL 237. It is situated in the IC348 target region in... 020
HOYS @hoys.bsky.social · 01/05/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 329 - HOYS Citizen ScienceSometimes you are analysing your data to find out something about it, and while contemplating your results you realise that you answered another question, much more interesting than the one you had in... 050
HOYS @hoys.bsky.social · 29/04/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 328 - HOYS Citizen SciencePlease enjoy this picture while I am on a break. We are back with interesting light curves next week :-) Apologies - I forgot to post this last week .... 050
HOYS @hoys.bsky.social · 29/04/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 327 - HOYS Citizen ScienceWe return to an old friend of the project this week. The young star V1490Cyg in the Pelican Nebula. The star has been the subject of one of our first papers, and we subsequently looked at its light cu... 030
HOYS @hoys.bsky.social · 29/04/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 326 - HOYS Citizen ScienceThis week we look at the light curve of the young star V1787Ori in the L1641N target region. We have looked at parts of the light curve for this object several times, for example in weeks 98, 201, 202... 020
HOYS @hoys.bsky.social · 07/04/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 325 - HOYS Citizen ScienceIn week 110 (more than 4 years ago) we had a look at the star BL Vel, which is situated in the southern HOYS field of Gaia19eyy. Back then we found that on occasion the star shows periodic variability... 030
HOYS @hoys.bsky.social · 28/03/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 324 - HOYS Citizen ScienceWe have a look at the V, R, and I-band photometry for the star T-Ori this week. We only show the data from the last observing season, i.e. the winter of 2024/25. The star is placed near a bright filam... 060
HOYS @hoys.bsky.social · 20/03/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 323 - HOYS Citizen ScienceThis week we look at the light curve of the variable star GQ Mon. It is situated in the NGC2264 target region and classified as a T Tauri star. We have now nine observing seasons worth of data - but ... 050
HOYS @hoys.bsky.social · 20/03/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 322 - HOYS Citizen ScienceWe are back looking at a light curve this week. The image above shows the V, R, and I-band data we have for the star V594Ori. It is situated to the South East of the Orion Nebula in the L1641N target ... 040
HOYS @hoys.bsky.social · 10/03/2025hoys.space/hoys-lco5-pi... 🔭hoys.spaceHOYS-LCO5 Picture Competition - HOYS Citizen ScienceOur teacher training program HOYS-LCO5 is slowly coming to an end. This year 12 teachers with just over 100 pupils from 9 countries signed up to learn how to observe […] 080
HOYS @hoys.bsky.social · 07/03/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 321 - HOYS Citizen ScienceWe remain with images of HOYS target regions this week. Usually we create colour composites but this time we show a false colour representation of a deep I-band wide-field image taken of the NGC1333 c... 0100
HOYS @hoys.bsky.social · 26/02/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 320 - HOYS Citizen ScienceThis week we have a look at another of the images from one of our target regions. The young cluster NGC2244, which is surrounded by the Rosette Nebula, is easily visible at the moment in the evening s... 070
HOYS @hoys.bsky.social · 20/02/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 319 - HOYS Citizen ScienceAs promised in last weeks post, we have another look at the old friend of the project, KH15D this week. In the two images above we compare the I-band light curves for the object for the observing seas... 071
HOYS @hoys.bsky.social · 15/02/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 318This week we have a look at one if the latest images that has been submitted. It is the southern half of the NGC2264 target region, where the Cone Nebula is situated. We show the colour combination i... 0172
HOYS @hoys.bsky.social · 10/02/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 317In the field of the eruptive, EX-Ori type, variable Gaia19fct, we find the variable object IRAS 07063-1016 or 2MASS J07084063-1021246. We show the V, R, and I-band data we have collected in the plot a... 050
HOYS @hoys.bsky.social · 10/02/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 316The above light curve of the object V2492Cyg looks like any of the ones we have shown before. That is true! But the way the light curve was made is very different to all the ones we have show before. ... 040
HOYS @hoys.bsky.social · 24/01/2025hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 315This week we have a brief look at Gaia19eyy. This is not a young star, but an erupting Be star in one of our fields. We have already written a paper about it, but we keep an eye on it since it got det... 170
HOYS @hoys.bsky.social · 17/01/2025This week we are following up two posts from weeks 268 and 306. These were about the star that seemed to have two periods in close proximity to each other. hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 314This week we are following up two posts from weeks 268 and 306. These were about the star that seemed to have two periods in close proximity to each other. These two periods were either near two days ... 020
HOYS @hoys.bsky.social · 11/01/2025This week marks the 6th anniversary of our light curve of the week feature! To ‘celebrate’ we show one of the less remarkable light curves, that do not get much attention usually. hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 313This week marks the 6th anniversary of our light curve of the week feature! To 'celebrate' we show one of the less remarkable light curves, that do not get much attention usually. In the above plot w... 050
HOYS @hoys.bsky.social · 30/12/2024hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 312Recently (Nov 23rd, 2024) Gaia flagged up the star MO Mon as an alert object Gaia24djm. It is situated at the edge of a small dark cloud next to the Cone Nebula. It got flagged up due to a ~1ma deep d... 080
HOYS @hoys.bsky.social · 16/12/2024This week we look at the young star TT Ori, which is situated just North of the Orion Nebula M42. It was flagged up by Gaia as an alter (Gaia22ehy) some years back.🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 310This week we look at the young star TT Ori, which is situated just North of the Orion Nebula M42. It was flagged up by Gaia as an alter (Gaia22ehy) some years back. We have looked at parts of its ligh... 030
HOYS @hoys.bsky.social · 13/12/2024This week we have a look at an old friend of this feature, the variable V350Cep in the NGC7129 cluster. ... Since two years now the source has changed its behaviour! 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 309This week we have a look at an old friend of this feature, the variable V350Cep in the NGC7129 cluster. Since it's 4mag brightness increase in the 1970's the object has roughly remained at its bright ... 030
HOYS @hoys.bsky.social · 06/12/2024Remember the object Gaia24ala which we posted about in week 266? It got flagged up by Gaia due to a sudden drop in brightness on top of a longer term dimming event, making it about 2mag fainter at about JD=2460335 – late January, 2024. hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 308Remember the object Gaia24ala which we posted about in week 266? It got flagged up by Gaia due to a sudden drop in brightness on top of a longer term dimming event, making it about 2mag fainter at abo... 050
HOYS @hoys.bsky.social · 30/11/2024hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 307This week we look at some progress we are making on the analysis of rotation periods. The last time we looked at this was in week 285, where we had a preliminary list of rotation periods. We have now ... 040
HOYS @hoys.bsky.social · 25/11/2024hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 306This week we bring a timely reminder of our upcoming observing campaign for the Sigma-Ori target field. The campaign will start 23.11.2024 and last for 2 weeks until 8.12.2024. The aim is to observe t... 030
HOYS @hoys.bsky.social · 25/11/2024hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 305One of the issues with our quite in-homogeneous data is that it can contain photometric outliers. In other words, these are brightness measurements which appear to have a small uncertainty but do not ... 010
HOYS @hoys.bsky.social · 25/11/2024 hoys.space/lightcurve-o... 🔭hoys.spaceLightcurve of the week 304After 9 light curves in last week's post, we have a look at an image this week :-) As many of our observers already know we have an extended 2-week 'campaign' coming up for the Sigma-Ori target field... 061
HOYS @hoys.bsky.social · 07/10/2024Welcome to the 300th light curve of the week post!!!!! 🙂 That is now almost 6 years of weekly posts. We started that feature on January 7th, 2019 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 300Welcome to the 300th light curve of the week post!!!!! :-) That is now almost 6 years of weekly posts. We started that feature on January 7th, 2019, and the first post read: Lightcurve of the week #... 010
HOYS @hoys.bsky.social · 01/10/2024This week we have look at the light curve of the young variable star GM Cep. It is situated in the elephant Trunk Nebula target region, and we have looked at it a few times before. 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 299This week we have look at the light curve of the young variable star GM Cep. It is situated in the elephant Trunk Nebula target region, and we have looked at it a few times before (e.g. in weeks 171 ... 000
HOYS @hoys.bsky.social · 19/09/2024With the start of our new HOYS-LCO project for this year imminent, we have a look at another image of one of our HOYS target regions. This week we feature the Elephant Trunk Nebula, or IC1396A. This ‘globule’ is part of a much larger HII region... 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 297With the start of our new HOYS-LCO project for this year imminent, we have a look at another image of one of our HOYS target regions. This week we feature the Elephant Trunk Nebula, or IC1396A. This '... 040
HOYS @hoys.bsky.social · 11/09/2024This week we look at the light curve of the namesake of one of our target fields, the young star V555Ori, which is situated about a degree North of the Orion Nebula. It was flagged up in 2017 as a variable Gaia17afn... 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 296This week we look at the light curve of the namesake of one of our target fields, the young star V555Ori, which is situated about a degree North of the Orion Nebula. It was flagged up in 2017 as a var... 000
HOYS @hoys.bsky.social · 04/09/2024This week we look at the R and B-Band light curve of the young star AHOri, situated just North of the Orion nebula. 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 295This week we look at the R and B-Band light curve of the young star AHOri, situated just North of the Orion nebula. We have looked at the long term behaviour of the object in week 173. It was showing... 010
HOYS @hoys.bsky.social · 28/08/2024This week we have another look at the fascinating case of the young star KH15D, or V582Mon. It is situated near the Cone Nebula, just south of the NGC2264 cluster.🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 294This week we have another look at the fascinating case of the young star KH15D, or V582Mon. It is situated near the Cone Nebula, just south of the NGC2264 cluster. We have looked at this source in we... 010
HOYS @hoys.bsky.social · 22/08/2024HOYS stands for Hunting Outbursting Young Stars and one of our aims from the start was to provide long term, pre-outburst light curves for the largest of the known bursts, the FU-Ori type outbursts. 🔭 hoys.space/lightcurve-o...hoys.spaceLightcurve of the week 293HOYS stands for Hunting Outbursting Young Stars and one of our aims from the start was to provide long term, pre-outburst light curves for the largest of the know bursts, the FU-Ori type outbursts. We... 020