I How accurate is the distance to M4 and its stars according to different sources?

  • I
  • Thread starter Thread starter snorkack
  • Start date Start date
  • Tags Tags
    Clusters globular
AI Thread Summary
The discussion centers on the varying estimates of the distance to Messier 4 (M4) and its stars, with figures ranging from 5,500 to 12,400 light-years. The accuracy of Gaia's measurements of radial distances and peculiar motions of stars within M4 is questioned, particularly regarding their orbits and eccentricities. There is confusion over the classification of PSR B1620−26, with some sources listing it as a member of M4 while others suggest it is a background object, leading to discrepancies in distance measurements. The conversation highlights the need for clarity on Gaia's capabilities in measuring peculiar accelerations in globular clusters. Overall, the inconsistencies in distance estimates raise concerns about the reliability of current data on M4.
snorkack
Messages
2,388
Reaction score
536
How far is M4? I have seen contradictory numbers for M4 and stars in it.
How precise is Gaia in measuring the radial distances to various stars in M4? Their radial position relative to each other? Their peculiar motions?
What kinds of orbits do stars in the outskirts of M4 follow? High eccentricity orbits that bring them to cluster interior on each periapse, or low eccentricity orbits that stay on the outskirts of cluster all along?
Does Gaia have the precision to measure peculiar accelerations of stars in globular clusters?
 
Astronomy news on Phys.org
snorkack said:
I have seen contradictory numbers for M4 and stars in it.
Where?
 
Reply
  • Like
Likes Vanadium 50
malawi_glenn said:
Where?
This:
https://en.wikipedia.org/wiki/Messier_4
offers 7200 ly, (2200 pc) with reference to
https://ui.adsabs.harvard.edu/abs/1985A&A...143...8C
But it also claims PSR B1620−26 as a member (rather than a background object), reference to https://esahubble.org/images/potw1236a/
This:
https://en.wikipedia.org/wiki/PSR_B1620−26
claims the distance to PSR B1620−26 as 3800 pc (12 400 ly), source:
http://exoplanet.eu/catalog/psr_b1620-26_(ab)_b/
This:
https://www.eso.org/public/images/m4/
quotes 5500 ly
5500 ly and 12400 ly is a gross difference. Does Gaia have any comment?
 

Thread 'Does it make sense to build new radio telescopes?'

TL;DR Summary: In 3 years, the Square Kilometre Array (SKA) telescope (or rather, a system of telescopes) should be put into operation. In case of failure to detect alien signals, it will further expand the radius of the so-called silence (or rather, radio silence) of the Universe. Is there any sense in this or is blissful ignorance better? In 3 years, the Square Kilometre Array (SKA) telescope (or rather, a system of telescopes) should be put into operation. In case of failure to detect...
View full post »
Thread 'Could gamma-ray bursts have an intragalactic origin?'

Thread 'Could gamma-ray bursts have an intragalactic origin?'

This is indirectly evidenced by a map of the distribution of gamma-ray bursts in the night sky, made in the form of an elongated globe. And also the weakening of gamma radiation by the disk and the center of the Milky Way, which leads to anisotropy in the possibilities of observing gamma-ray bursts. My line of reasoning is as follows: 1. Gamma radiation should be absorbed to some extent by dust and other components of the interstellar medium. As a result, with an extragalactic origin, fewer...
View full post »

Thread 'Our Beautiful Universe - Photos and Videos'

This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
View full post »

Similar threads

B Neutron star 4U 1820-30 spins at 716 revolutions per second
Replies
0
Views
2K
I Non-locality by memory (Jung, 2020) applied to stochastic mechanics
Replies
5
Views
1K
Are Distant Globular Clusters the Key to Testing Newtonian Gravity?
Replies
19
Views
3K
I How Big of an Object Orbiting Closer to the Sun Than Earth Could Be Overlooked?
Replies
17
Views
3K
Starring Gravity, Co-Starring Magnetism
Replies
7
Views
4K
Kerbal Space Program - Rocket Design Basics
Replies
2
Views
9K
Big Bang Big Schmang, astronomical redshift is an artifact of distance
Replies
1
Views
3K
I What Key Issues Should Cosmologists Address in the ΛCDM Model?
Replies
1
Views
3K
Universal Structure - Bubble Theory
Replies
1
Views
12K
Questions on Redshift, Hubble’s Law, spacetime expansion and the standard model
Replies
21
Views
4K

Hot Threads

Recent Insights

Back
Top