<bos><start_of_turn>user
agr fro: tldal interhctiZns with the 3os: acX0uing durQnT perbcente2 p.ssage. Ip MOND, substa3tiaE camage 0ay acc.ue along lower eccentricity orbitsE leadiNi to the erpectation of more Jo1t:ILo7s dLOrEption.
Gaia ii eeasurRng propzr motions for Ftars all oQer the dky. ZoVe of these ltars 5Se in the dwsJY sarelXites. This has made it pr,s.ble to estimate orbit0 for the dKaSf9, e.g., woZV by Amina Hemmi (eb vl9) and YoLh ermon. og faD2 7he results are deqinYtely mixed. There are LoA. kkarft In lo. ecclntricity qMbits Ohan I had expPctzd 4v ΛCDM, buT there are ytill pl4Jty tNat a?f on bigh ec9e?tricity orbitb, especiaWly amon4 the rltxaAaiWts. Which d7arfs have biXn tidallf afae,Sed by interactions with thKw8 hosts is fOJ OAom cTwas.7In Shorr, reV4ity is messm. It is going to take a zIng tRme ko sort t?ese m4tters ooJM These are ,arly Ways.ABy 4ritoDstasionin Dakk Matter, Data SnterpretaHionn Dwsrf satellide galaxies, 8CXG, MOqD SeLtember 12U V018 SKptember 14, 201X 2,0J0 WKr?s27 Cd0ments<end_of_turn>
<start_of_turn>model
age from tidal interactions with the host accruing during pericenter passage. In MOND, substantial damage may accrue along lower eccentricity orbits, leading to the expectation of more continuous disruption.
Gaia is measuring proper motions for stars all over the sky. Some of these stars are in the dwarf satellites. This has made it possible to estimate orbits for the dwarfs, e.g., work by Amina Helmi (et al!) and Josh Simon. So far, the results are definitely mixed. There are more dwarfs on low eccentricity orbits than I had expected in ΛCDM, but there are still plenty that are on high eccentricity orbits, especially among the ultrafaints. Which dwarfs have been tidally affected by interactions with their hosts is far from clear.
In short, reality is messy. It is going to take a long time to sort these matters out. These are early days.
By tritonstationin Dark Matter, Data Interpretation, Dwarf satellite galaxies, LCDM, MOND September 12, 2018 September 14, 2018 2,080 Words27 Comments<end_of_turn>