#2 - Concept Reference, Must Be True

[Administrator]

Complete Question Explanation

The correct answer choice is (D).

Answer choice (A):

Answer choice (B):

Answer choice (C):

Answer choice (D): This is the correct answer choice.

Answer choice (E):


This explanation is still in progress. Please post any questions below!

[DVD]

The question asks what is mentioned in the passage as evidence that Herculina has a satellite.

The passage says that astronomers found two distinct drops in brightness, one of which preceded the predicted occultation, and "the presence of a secondary body near Herculina thus seemed strongly indicated". So the occultation that occurred shortly before the predicted occultation provides evidence that a secondary body was present near Herculina, not that such body was a satellite.

Although there is no better answer choice than D, the question seems a little misleading because it doesn't ask for, e.g., what best describes evidence provided to demonstrate that Herculina had a satellite. The question is instead much more precise and extreme: it asks what is mentioned as providing evidence that Herculina had a satellite, and the correct answer choice does not exactly state that.

[Francis O'Rourke]

Around line 15, the author states that observations now suggest that asteroid satellites exist in reality. A few lines later, the author introduces Herculina as the most convincing of such reports. The reason that the author includes this here is clearly to give us an example of a report of an asteroid satellite.

Although you may disagree with the author about what the evidence proves, the passage clearly introduces the Herculina double occulation report as evidence for an asteroid satellite. Remember to read the passage more broadly if you get stuck on answer choices such as this. It seems that you were focusing on lines 25-30, while ignoring the what the author wrote in lines 1.4-22

[demk26]

I think the language of Answer (D) is what confused me.

It says: "the occultation that occurred shortly before the predicted occultation by Herculina" but what I think it is really saying (or a more concise way to say it) would be: "the occulation (by Herculina) that occurred shortly before the predicted occulation (meaning the occulation of the asteroid).

My reasoning for ruling out my other contender, Answer (E) is that the passage writes: The other, which lasted about five seconds, preceded the predicted occulation by about two minutes. The presence of a secondary body near Herculina thus seemed strongly indicated.

The text is saying that it wasn't the precise timing of the Herculina occulation that led us to believe it was a satellite, but rather the fact that it preceded the predicted occulation.

Am I correct in my reasoning here?

Thanks so much for your help, PS!

[Jeremy Press]

Hi demk,

You're fine, it's just that you've confused Herculina for its satellite. Herculina is actually the asteroid (see line 21), and its satellite is what caused the initial occultation. Herculina the asteroid then followed it up, causing the predicted later occultation. Astronomers knew about Herculina and were expecting it (they'd predicted it) to pass in front of the star. But they saw something else (the presumed satellite of Herculina) pass in front of the star first. That something else was the "secondary body near Herculina." Don't get tripped up by the term "secondary," as it's only referring to a smaller body associated with the larger asteroid Herculina. It's not referring to the time when that body passed the star.

Let me know if this clears things up for you!

Jeremy