Please note: send all correspondence to me only at: terrymosel@aol.com
1. IAA Lecture, Wed 27 November, 7.30 p.m., Larmor Lecture Theatre, Physics building, QUB: "The Hiccups of Massive Stars" by Dr Charlotte Angus, Research Fellow, Astrophysics Research Centre, QUB (Apologies, the date in my last bulletin was wrong, now corrected!)
Abstract: Massive stars play a fundamental role in sculpting the chemical make up of the Universe. Yet our understanding of how these stars actually evolve is incomplete. In extremely massive stars, we predict that they should experience violent pulsations towards the end of their lives. These pulsations would be strong enough to remove entire layers from the outer regions of the star. However, we have so far not been able to observationally confirm that such phenomena take place. In this talk I will explore the physics behind these giant stellar hiccups, and how we might begin to search for them in the night sky.
Biography: Dr Charlotte Angus is a Research Fellow at the Queen's University Belfast, working on a wide variety of exotic transient phenomena; from massive stellar explosions, to stars being shredded by black holes. She received her PhD at the University of Warwick in 2017, and has since worked as a postdoctoral researcher at the University of Southampton, then won a DARK Research Fellowship at the University of Copenhagen in 2019. Since moving to QUB at the end of last year, she has infiltrated the IAA, and accidentally been elected as its co-Vice President. She has yet to successfully solve one of Terry's Teasers.
Admission free, all are welcome, including Light Refreshments.
2. Saturn still well placed .
Saturn is still well placed for observing in Aquarius in the S as the sky darkens, although it's fairly low in our skies. It's mag 0.9, with a disc diameter of 17".
Notice how narrow the rings are now! The angle is only about 5 degrees, because of the apparent retrograde motion. But they will soon gradually get narrower as Saturn approaches its 'equinox' next March, in other words its equator and ring plane will be edge on to the Sun, and therefore almost edge on to the Earth. Observe it for as long as possible to see just how narrow they get!
Also look out for some of its many moons, Titan (8m.3) is easy to see in any telescope, Rhea is also fairly easy at 9m.7. Tethys (10m.2) and Dione (10m.8) are also fairly easy in a reasonable telescope. Enceladus (11m.7) and especially Mimas (12m.9) are challenging, but will be easier to see as the rings narrow and become less bright; they will be even easier to see next year as the rings narrow almost to invisibility.
3. Jupiter is well placed and brilliant!
It's now really bright in Taurus as it heads towards its opposition on 7 December. It's mag -2.6, with the disc diameter an impressive 48".
Even a 75mm telescope will show the Great Red Spot when it's on or near the meridian. Binoculars will show the 4 big Galilean Moons, Io, Europa, Ganymede and Callisto, and a moderate telescope will show at least the start and end of their transits across the disc. That's because the edge of the planet is darker than the middle due to 'limb darkening', so the bright satellite shows up against the dark background. But when the satellite is near the middle of the disc, the contrast with the brighter background is much less, and it takes a big telescope and steady seeing to reveal the satellite.
However, the much darker shadows of the satellites are easy to see the whole way across the disc. Also interesting to watch, and easier to see, are the satellites entering and leaving eclipse in Jupiter's shadow, except very near opposition when this happens very close to the disc itself, as now.
At the moment, the outer Moon, Callisto, does not undergo any of these phenomena, because of the orbital tilt at present, so it always passes just above or just below the disc of Jupiter each orbit.
| 4. Venus creeping up into the SW evening twilight. The Evening Star is starting to live up to its name, creeping out from the solar glare, and eventually becoming quite well placed just in time for Xmas. It's quite obvious now, in the evening twlight not long after sunset. It's magnitude -4, with a disc diameter of 16".
5. MARS The Red Planet is now becoming more prominent late in the night, in Cancer, but not too far from Castor and Pollux in Gemini. It's magnitude -0.3, but still very small with an apparent diameter of only 10.8". It will get brighter and bigger as it approaches opposition on 16 January.
6. URANUS: Is still well placed for viewing now, in Taurus, near the border with Aries, at mag 5.7, after its opposition on 17 November. But with an apparent diameter of only 3.7", even large telescopes will show only a small bluish disc.
7. ISS. The ISS continues its series of evening passes until 6 December. See www.heavens_above.com for details |
8. IAA Annual Subscriptions. Subscriptions were due on 1 September. Members who have not renewed will not get the next issue of STARDUST
See https://irishastro.org/join-the-iaa/
Membership of the IAA costs £20 (€25) per year for Individual Membership or £25 (€30) per year for Family Membership (all members of a family at one address) from September to August and entitles members to attend all IAA events including our regular speaker programme. Also, there are four issues of the IAA magazine "Stardust" produced annually and these will be delivered to your home address.
If you are a UK taxpayer, please select the 'gift-aid' box, as that enables us to reclaim the standard rate of tax on your subscription, at no cost to you. You can also make a donation via Paypal if you wish: just click on the 'Donate' button. See also http://www.irishastro.org/ https://irishastro.org/
9. Recurrent Nova T Corona Borealis – SEE LATEST NEWS, at end of this item
I hate to have to say – "I told you so." OK, that's not true – everyone likes to know that they've been right, when they've gone out on a limb!
There were reports on social media in early March that T CrB was due to explode again in the next week or two, i.e. in late March: I stuck my neck out, and said that we couldn't predict the next outburst with that degree of accuracy. That period has now well passed, so I was right.
There have since been several more articles, saying much the same thing, and it still hasn't happened. The position remains the same - It could explode tomorrow – or not for another year or more! It's normally around magnitude 10 but in 1946 it faded to about 11 just before the outburst, but at outburst it reaches mag 2.0 or 2.5.
The first outburst was discovered by Irish astronomer John Birmingham in Tuam, Co Galway, in May 1866. Earlier archive observations indicate possible previous outbursts in 1217, 1787, as well as 1866 & 1946. The eruptions in 1787, 1866 and 1946, indicated an approximate 80 year period. BUT you can't assume a period from only 2 intervals ! However, in the year before the 1946 outburst, it dimmed to magnitude 12.3, and this has happened again recently, suggesting a possible outburst is imminent. BUT, once again, you can't predict from a single event!
Incidentally, the gap from 1217 to 1787, assuming some eruptions that were not observed, gives a
period of 81.4 years if there were 7 outbursts, so that's fairly constant!
As I've said many times, while there are records of several previous explosions, we only have a sample of one set of detailed observations of the pre-explosion stage – in 1946. And it's always dangerous to extrapolate from one set of observations!
So, keep an eye on it - comparison charts can be found on the websites of the BAA Variable Star Section, or the AAVSO. The current magnitude is around 10, so you'll need a good telescope to see it now.
(BTW, don't confuse it with the other nearby famous variable star, R CrB, which does the opposite – it stays normally around 6th magnitude, but occasionally dims to as faint as magnitude 14 or 15!)
(And for comparison, the other not quite so well-known recurrent nova, RS Oph, was seen to, or is thought to have, erupted 9 times since 1898 – with intervals of approximately 9, 26, 12, 13, 9, 18, 21 and 18 years; so its period is by no means constant.)
Anyway, do keep an eye out – T CrB lies just outside the East side of the circle of the 'Crown', about a degree from Epsilon CrB, but you really do need charts to observe it properly. It's getting in the W as the bright twilight ends, about 25 degrees to the left of Arcturus.
But, although it's not circumpolar, it's far enough North that when it's no longer visible in the West after sunset, it's visible in the morning sky in the East before sunrise.
It's at Declination: 25° 55′ 12.613″; R.A.: 15h 59m 30.1622s
See also https://www.facebook.com/share/39XnUDPUGgsnmMDG/
And now this! Talk about a misleading headline!?! Much-awaited star explosion is finally here. How to watch it and where to look https://www.wionews.com/science/much-awaited-star-explosion-is-finally-here-how-to-watch-it-and-where-to-look-762377
LATEST - REALITY BITES!
Now they're saying "sometime this year" – and also, in the same article "within the next couple of years" ! What Is the 'Zombie Star' Set To Come Back to Life According to NASA? - Newsweek and this –
Another article with misleading statements and irrelevant illustrations ! A rare stellar explosion is coming: the first in 80 years
FINALLY - Someone else confirms what I've been saying since early March!
T Coronae Borealis: Why the mysterious star still remains unexploded
See near the end - "When should we expect an explosion?"
10. Moon Occults Saturn, 4 January.
The waxing 5 day old crescent Moon will occult Saturn on the early evening of Saturday 4 January. This will be a beautiful sight, with the Earthlit ghostly lunar limb slowly approaching and covering the Rings and then the planet. The Moon will not be so bright as to drown out the satellites, so at least the occultation of Titan should also be visible in a moderate telescope. More details later, but save the date!
We hope to have a public observing event for this occultation in front of the main building at QUB: details TBC
11. Irish Astronomy Week 2025; March 1st to 8th.
Ronan Newman launched this event, which was a great success last year, but due to personal circumstances he won't be so involved in the next one. So it will be up to individual clubs to organise their own events,
See https://www.facebook.com/share/1B124rbzHv/
And https://www.facebook.com/share/18UAaWnbBB/
12. Total Lunar Eclipse, 14 March. This occurs in the pre-dawn sky, as the Moon is getting very low. The start of totality is just visible here before the Moon sets.
13. Partial Solar Eclipse, 29 June. The magnitude will be over 50% for all of Ireland, with NW Mayo getting 57%. We hope to organise at least one public observing event for this eclipse.
14. INSAP, QUB, 9-12 June, and at AOP, 13 June.
15. European Astronomy Society 2025 meeting in Cork 23-27 June 2025
16. ALAN 2025, 28 – 30 October 2025, Westport.
Preparations are under way for the 9th Scientific Conference on Artificial Light At Night, ALAN2025, from October 28-30, 2025, in Westport, Ireland. Our host will be Dark Sky Ireland. The invited speakers will be revealed soon, but we can already promise you interesting talks about science, governance, dark sky outreach, and lighting design.
The conference offers a platform for interdisciplinary networking and exchange on the topics Biology & Ecology, Governance & Regulations, Health, Measurements & Modelling, Social Sciences & Humanities, Technology & Design.
We welcome researchers, lighting professionals, policy makers, light pollution activists, and everybody who is interested in the effects of artificial light at night. The conference aims to present new findings, exchange experiences and ideas, network, and discuss hoe artificial light can be used with less negative impacts.
I'm on the organising committee for this event, so I'll keep you posted regarding the programme.
For more information check out our website at artificiallightatnight.org .
17. DIFFICULT TEASER - No Winners!
Q. What's the connection between a moon of one planet and a mission to explore a different planet?
No correct answers yet, so here's a clue: The second planet is one of the outer solar system planets.
Peter Denman - Right but Not Right! Peter submitted the following -
"Voyager 1's encounter with Titan bent the spacecraft's path northward [out of the ecliptic plane]. Had Titan not been satisfactorily imaged, the Voyager 2 would have been targeted to carry out a survey, so losing an opportunity to rendezvous with either of the outer giant planets."
However, while that is an answer, it's not correct, because it involves two different missions, (V1 & V2). What I'm looking for involves one mission only.
Peter then came up with another answer, in which he identified one half of the answer, but the other part was not what I'm looking for. Still, his answer was correct in its own sense, so I'll give him an honourable mention. So, well done Peter, but the teaser is still open.
One more clue: The second planet is Jupiter.
Another clue: The other planet (with the moon) is a neighbour of Jupiter.
I might win this one! Just one more clue, and then I'll close it –
The other planet, with the Moon in question, is Saturn.
I WIN!
No correct answers, so here it is:
ANSWER: JANUS is a camera on JUICE. Janus is a moon of Saturn, whereas JUICE will explore Jupiter. It is an acronym for the Latin phrase Jovis, Amorum ac Natorum Undique Scrutator, which translates as "Scrutinizer of Jupiter, and all his loves and descendants" – Jupiter's Galilean moons Io, Europa, Ganymede and Callisto are all named after lovers of Zeus (Jupiter to the Romans) in Greek mythology.
18. Easy Teaser – No Winners :
What does the number 12.368265923 represent? (It's only because I'm an absolute nerd that I give the figure to that degree of accuracy! If you take 12.368 it will be close enough!)
ANSWERED – BUT NOT ANSWERED! Jim Verner got it right, but as a previous winner, he's not eligible to answer the Easy ones anymore. So, it's still open.
Clue. It relates to time.
OK, another clue: What's the nearest whole number to that?
Final clue: There are 12 calendar months in a calendar year, but…..
No One who was eligible got it right, although Jim Verner did (see above).
ANSWER: It's the mean number of lunar months (i.e. FM to FM) in a tropical (normal) year
19: New Difficult Teaser:
Which comet could be said to be linked to the Irish Astronomical Association?
20: New Easy Teaser
What recurring thing in Star Trek is statistically very very unlikely? Apart from the fact that every civilisation in the galaxy speaks English!
CLUE: It usually occurs at or near the start of each programme.
Remember, only send answers to me at my aol address: terrymosel@aol.com.
21. INTERESTING WEBLINKS (Disclaimer – Use of material herein from various sources does not imply approval or otherwise of the opinions, political or otherwise, of those sources). NB: If the title in the weblink does not indicate the subject matter, I give a brief simple intro before the link. I may also comment about the link afterwards.
ASTROPHYSICS:
James Webb Confirms Hubble's Calculation of Hubble's Constant - Universe Today
Sun-Like Stars Around Black Holes: What Gives? - Universe Today
Three More "Galactic Monster" Ultra-Massive Galaxies Found - Universe Today
Scientists watch hardcore object blasting energy beams into space | Mashable
The Strange Pulsar at the Center of the Crab Nebula - Universe Today
James Webb Space Telescope 'pushed to its limits' to see most distant galaxies ever
H.E.S.S. Reveals the Origins of Ultra-High-Energy Particles
'Impossible' black holes discovered by the James Webb telescope may finally have an explanation
Unusual black hole light bursts puzzle astronomers: 'We are finding a lot of weird stuff'
COSMOLOGY:James Webb Space Telescope 'pushed to its limits' to see most distant galaxies everScientists discovered 'secret life' of the universe before the Big Bang 'Impossible' black holes discovered by the James Webb telescope may finally have an explanation
EARTH & MOON This is very bad news for UK & Ireland Key Atlantic current is weakening much faster than scientists had predicted
Earth bids farewell to 'mini moon' that's been tagging along for months
Earth has tilted by 31.5 inches and humans are to blame – here's why it matters
EXOLIFENASA tests tiny robots for a mission to explore icy moons Scientists are updating chemistry models to track down life on icy moons EXOPLANETSUp to a Third of Stars Ate Some of their Planets - Universe Today First it says it's 800,000 LY from us, which would put it beyond the far side of our own Milky Way Galaxy, and basically unobservable. Then it says it's 500 LY from us, which is much more reasonable. But that first sub-headline needs to be corrected. Youngest exoplanet discovery sheds light on early planet formation
IMAGES:
The Sombrero Galaxy's star-forming days are nearly over — and the James Webb Space Telescope may know why SOLAR SYSTEM NASA tests tiny robots for a mission to explore icy moons Scientists are updating chemistry models to track down life on icy moons Mission to Psyche: One Year Into the Spacecraft's Journey to a Metal-Rich Asteroid | WatchMars may have made its 2 moons by ripping an asteroid apart
Martian ocean could be 3.6 billion years old as water found in Red Planet's crust NASA's nuclear-powered Dragonfly helicopter will ride a SpaceX Falcon Heavy rocket toward Saturn moon TitanSpace photo of the week: Hubble uncovers the true identity of an odd galaxy — and it's not spiral or ellipticalScientists 'discover ocean shoreline on Mars' that could be biggest indicator of life yet NASA spots mysterious 'spiderwebs' on never explored region of MarsEvidence of hot water that's essential to life points to Mars' habitable past Curiosity rover uncovers rare sulphur crystals on Mars SPACE The New Mars Landing Approach: How We'll Land Large Payloads on the Red Planet - Universe Today
What Should Light Sails Be Made Out Of? - Universe Today
Norah Patten Foundation. Norah, who hopes to be the first person from ROI to travel into space, has set up this foundation https://www.facebook.com/share/1XC5opLsvm/
Why is Starship made of stainless steel? https://www.facebook.com/share/p/15W6QUUmg5/
Mission to Psyche: One Year Into the Spacecraft's Journey to a Metal-Rich Asteroid | Watch
Space breakthrough: Nasa craft receives signal from depths of the solar system
NASA's ISS crew in panic after cargo ship arrives with 'toxic smell'
How amateur radio is connecting astronauts in space with kids on Earth
Starship (and Donald Trump) Make a Splash at Sixth Flight Test
SUN
Meet the Parker Space Probe: a spacecraft trying to solve the Sun's biggest mystery
TELESCOPES, EQUIPMENT & TECHNIQUES
New more accurate equation for the Gravitational Bending of Light accurate equation for the gravitational bending of light by a static massive object | Monthly Notices of the Royal Astronomical Society | Oxford Academic The Sun is not static, and it does rotate, but I presume that neither effect is large enough to affect these calculations.
FINAL WORD:
"The treasures hidden in the heavens are so rich that the human mind shall never be lacking in fresh nourishment." - Johannes Kepler
22. JOINING the IRISH ASTRONOMICAL ASSOCIATION. This link gives options to join the IAA.
https://irishastro.org/join-the-iaa/ If you are a UK taxpayer, please select the 'gift-aid' box, as that enables us to reclaim the standard rate of tax on your subscription, at no cost to you. You can also make a donation via Paypal if you wish: just click on the 'Donate' button. See also http://www.irishastro.org/https://irishastro.org/
The Irish Astronomical Association is registered with The Charity Commission for Northern Ireland NIC 105858
DISCLAIMER: Any views expressed herein are mine, and do not necessarily represent those of the IAA.
Clear skies,
Terry Moseley
