Questions tagged [infrared]

Questions about infrared astronomy, both observations (in the broadest sense) and instruments. The infrared part of the electromagnetic spectrum has a longer wavelength than visible light, but shorter than sub-mm or radio waves.

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Why aren't ground-based observatories using adaptive optics for visible wavelengths (circa 2016)?

Adaptive Optics (AO) techniques allow ground based observatories to dramatically improve resolution by actively compensating for the effects of Astronomical Seeing. The atmospheric effects are quite ...
uhoh's user avatar
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11 votes
1 answer
608 views

Was GRAVITY built to look at one star?

GRAVITY (shown below) is a interferometric combiner of near infrared light from four very large telescopes called The Very Large Telescope in order to make careful astrometric measurements near the ...
uhoh's user avatar
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10 votes
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Why was helium hydride (HeH+) the universe's first molecule?

The abstract of the new Nature paper Astrophysical detection of the helium hydride ion HeH+ tell us that infrared spectroscopy from SOFIA detected ...rotational ground-state transition of HeH+ at a ...
uhoh's user avatar
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10 votes
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V471 Tauri's circumbinary brown dwarf non-observation; Applegate, or over-restrictive assumptions?

tl;dr Has the brown dwarf observation been disproven? I have just started reading about the interesting object V471 Tauri. The first two sentences of the introduction to The V471 Tauri System: A ...
uhoh's user avatar
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9 votes
1 answer
725 views

Why is detecting brown dwarfs difficult?

Why is detecting brown dwarf stars tedious and not always successful? They emit light in the infrared region, and given that we're surrounded by state-of-the-art technology in space today, why haven't ...
Pranay's user avatar
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9 votes
1 answer
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What is the projected range of the JWST to be able to detect exoplanet atmospheres?

Yesterday the K2 mission detected transit events of objects passing in front of a number of M dwarfs which could turn out to be rocky planets. If some of these planets host atmospheres, could the JWST ...
dualredlaugh's user avatar
8 votes
1 answer
313 views

What are the bright dots in some galaxies in the first JWST image?

In the first image released by the James Webb Space Telescope, some galaxies seem to have many bright dots - what are these? Young, huge stars? Supernovae? Just hot things behind the galaxy? (30 MB ...
2080's user avatar
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8 votes
2 answers
367 views

What makes small interferometers useful? Like NIRISS on JWST

NIRISS is an instrument on the James Webb Space Telescope. It has a "non-redundant aperture mask" which obviously covers most of the area of the sensor. It seems to be advantageous for high contrast ...
LocalFluff's user avatar
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8 votes
1 answer
148 views

Is there any correlation between the Cosmic Microwave Background (CMB) and the distribution of distant galaxies?

The Cosmic Microwave Background (CMB) is remarkably isotropic but does exhibit a distinct dipolar Doppler shift and also much smaller but measurable fluctuations in intensity and polarization. ...
Roger Wood's user avatar
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7 votes
2 answers
3k views

Which (if any) space telescope would have worked longer if it hadn't simply run out of helium?

In this answer to Why is the hot part of Webb's MIRI cryocooler in the 300K area? and comments below discusses the helium refrigerator used for cooling JWST's Mid-Infrared Instrument or MIRI. A ...
uhoh's user avatar
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7 votes
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Did they ever figure out why Parker's WISPR cameras were able to see the surface of Venus? Mischaracterized filter, or unexpected atmospheric window?

Credit: NASA/Johns Hopkins APL/Naval Research Laboratory/Guillermo Stenborg and Brendan Gallagher Also refer to the technical material cited in the Space Exploration SE question How brightly does ...
uhoh's user avatar
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7 votes
0 answers
140 views

Can terrestrial infrared telescopes see through clouds or haze, sometimes at least?

My answer to Could UV-A imaging sensor reasonably see a total eclipse in progress through clouds? suggests that while clouds blocking visible light observation of the (partially) eclipsed solar disk ...
uhoh's user avatar
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6 votes
1 answer
101 views

Why would the Chang'e-4 lander find lunar far side temp. "colder than scientists expected", when the LRO has already been taking thermal readings?

In January, the Chinese probe lander Chang'e-4 was was announced to have found temperatures dipping lower on the far side than expected ("Chinese rover finds lunar nights 'colder than expected'" by R. ...
Jacob C.'s user avatar
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How far have stars been seen beyond the center of the Milky Way?

What lies near the center of the galaxy is of great interest and in recent times the motion of dozen(s) of stars at the center of our galaxy orbiting around Sgr A* have been measured in great detail. ...
uhoh's user avatar
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5 votes
2 answers
429 views

Question: By design, JWST cannot observe in the anti-sun direction. Is this due to Gegenschein backscatter?

This question has been reposted from Space Exploration Gegenschein is a faint bright spot in the zodiacal light, centered at the antisolar point. By ESO/Y. Beletsky - ESO, CC BY 4.0, https://commons....
Woody's user avatar
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5 votes
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What is the infrared self-luminosity value of Jupiter and Saturn?

I'm looking for these data to apply them to the Kelvin-Helmholtz mechanism but I can't find the values. Or at least if there is an order of magnitude compared to the solar luminosity.
User13122015's user avatar
5 votes
2 answers
177 views

Which kind of strategy should we take to discover Planet 9 and other KBOs?

What are the differences between the discoveries of Sedna, 2012vp 113, and the supposed Planet 9? All need deep infrared surveys at the ecliptic plane, but P9 needs a much deeper survey?
questionhang's user avatar
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5 votes
1 answer
65 views

How to interpret illumination in "pulsar cannonball" image

This beautiful image (from APOD) looks like the trail of the ejected pulsar is illuminating a ball of gas and dust. My eye sees patches of light and shadow, but sometimes images can be deceptive. What ...
Mark Foskey's user avatar
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How to convert between AB and Vega magnitudes?

This might be a bit silly, but I'm really struggling with a conversion. I have apparent AB magnitudes: $$m_{AB} = -2.5 \log_{10}(f_\nu [\mu Jy]) + 25$$ that I would like to convert to Vega magnitudes, ...
theWrongAlice's user avatar
5 votes
0 answers
90 views

Infrared telescopes, magnitude and observations

Currently 22-23 magnitude could be the limit to make a spectrum for ground based 10m class telescopes, 21-22 magnitude may be easy for them. 4m class telescopes could possibly handle 20 magnitude, I ...
questionhang's user avatar
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4 votes
2 answers
243 views

Acetylene at Uranus? What's JWST's evidence and current thinking of how it's possible?

After about 03:22 in PBS Newshour's July 13, 2023 James Webb Space Telescope prompts scientists to rethink understanding of the universe JWST Interdisciplinary Scientist Heidi Hammel talks about ...
uhoh's user avatar
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4 votes
2 answers
223 views

Narrowband imaging wavelengths in NIR?

Lines giving useful (& beautiful) data in visible spectrum are well known - H-b, O-III, H-a, S-II. Unfortunately light pollution is strongest in visible light. Are there similar relatively bright ...
BarsMonster's user avatar
4 votes
1 answer
99 views

Why is infrared the ideal band to detect the earliest and most-redshifted galaxies? [duplicate]

Was infrared chosen for the James Webb Space Telescope's mission to detect the most-redshifted galaxies and stars in the universe because most detectable galactic radiation emits most strongly in the ...
Rich McDaniel's user avatar
4 votes
1 answer
98 views

Can we see atomic positronium lines in space? What could be learned from it and what are current challenges to doing so?

This answer to Have we detected spectra of exotic atoms in stars?1 currently ends: Estimates for observing lines corresponding to transitions between different bound states of positronium are not ...
uhoh's user avatar
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4 votes
1 answer
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Are features in the CMB correlated with features in the SDSS map of the most distant galaxies?

This is a follow up to an earlier question to which @pela gave an excellent answer. Apparently the statistics of the length-scales of the CMB fluctuations are similar to those obtained from other ...
Roger Wood's user avatar
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3 votes
2 answers
1k views

Is it possible for a planet to heat up its moon to habitable temperatures solely through infrared radiation?

Stars are powered by nuclear fusion and the energy released radiates through their surface as heat. But all objects radiate away some form of electromagnetic radiation depending on their temperature. ...
user177107's user avatar
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3 votes
1 answer
194 views

Is there an IRAM satellite that measures thermal radiation at 250 GHz, or was this a ground-based instrument?

The Nature Research Letter A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation (also here and here) says about half-way through: We now reassess Eris’ surface ...
uhoh's user avatar
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3 votes
1 answer
155 views

What are IRAS sources?

Do IRAS sources refer to star forming regions? I searched google and I came to know that it stands for IR astronomical satellite.But what do they search for? Please help me
Rian's user avatar
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3 votes
1 answer
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What exactly is the risk to any JWST instrumentation when looking at objects that are "too bright"?

This answer by pela to question #48317 at one point states The star should be bright, but probably not too bright (like Betelgeuse), since we don't want to burn MIRI off from the beginning A comment ...
Nij's user avatar
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3 votes
1 answer
183 views

Why is the "green" comet C/2014 Q2 (Lovejoy) red in this picture?

In this nice NYTimes 'survey article' "Our Vast Solar System and Its Many Explorers" there is a NEOWISE image of Comet C/2014 Q2 (Lovejoy). See here also. The NASA description of the image says: ...
uhoh's user avatar
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3 votes
1 answer
184 views

What does the celestial sphere look like in thermal IR?

The Space SE question JWST detector heat load asks ...what is the heat load from the collected radiation of the main mirrors on the detector, and how does that vary depending on what objects or ...
uhoh's user avatar
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3 votes
1 answer
130 views

Number of lenslets in wavefront sensor array

I have to do a short calculation, but, quite frankly, I have no idea how to even start... Suppose you have a 10-m telescope (f/10) with an infrared camera that observes at 10 micrometer. The seeing is ...
theWrongAlice's user avatar
3 votes
2 answers
163 views

Can a telescope detect a blackbody?

I'd like to determine the distance at which a telescope with a certain set of parameters (sensitivity, collector area) can detect a blackbody with certain other parameters (temperature, emitting area)....
Matterbeam's user avatar
3 votes
0 answers
95 views

How do JWST and Hubble compare in detecting small bodies in the solar system that are a) white, b) black, c) Arrokoth-like, d) Voyager-like?

Assume the object is small, spherical, and illuminated only by the Sun, and has some apparent motion. The object is either: a) white - reflecting 100% perfectly diffusely (assume low temperature) b) ...
Roger Wood's user avatar
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2 votes
1 answer
171 views

Can the WISE telescope detect black holes?

Black holes are hot, aren't they? With its infrared scan, could the WISE telescope also detect a black hole? The hypothetical planet beyond the Kuiper belt could actually be a primordial black hole. ...
user30007's user avatar
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2 votes
1 answer
179 views

What's that limit, where we start to see infrared galaxies?

All the nearby galaxies we see come in visible range, many are visible from ground based telescopes. And the farthest galaxy that hubble discovered recently, 13.4 billion light years away is in infra ...
Roxy's user avatar
  • 43
2 votes
1 answer
89 views

How do the stars in the near-infrared (NIR) radiate?

Let's say we are studying the integrated near-infrared (NIR) light of a distant spiral galaxy. We would expect most of this light to be dominated by red giants stars and dwarfs. I assumed these stars ...
Astroturf's user avatar
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2 votes
1 answer
74 views

What determines the surface material of the ALMA and Spitzer telescope?

The transition between metal dish and mirror happens around hundreds of microns. For example, the shortest wavelength the ALMA(metal dish) can detect is about 0.3mm, while the longest wavelength the ...
questionhang's user avatar
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2 votes
2 answers
58 views

How can photoionization release photons? As in the coronal emission of a nova star?

The photoionization process absorbs energy (light), it doesn't release it.... So how can some astrophysicists say that photoionization releases the light responsible for the coronal emission of a star ...
Kurt Hikes's user avatar
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2 votes
1 answer
74 views

How to calculate an infrared SED from the specific intensities?

I have values of total infrared fluxes (SED) in literature expressed in Jy (Jansky) for galaxies. I want to assure that my infrared radial profiles of the same galaxies in MJy/sr (and other in Jy/...
PsycOx's user avatar
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2 votes
1 answer
108 views

How can a 1-pixel image of a rotating asteroid be used to measure its thermal inertia?

Phys.org's Observatory in Chile takes highest-resolution measurements of asteroid surface temperatures ever obtained from earth discusses imaging of millimeter wave imaging of the surface of asteroid ...
uhoh's user avatar
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2 votes
1 answer
106 views

Is Sofia a radio telescope proper?

I usually think of SOFIA, the Stratospheric Observatory for Infrared Astronomy as an infrared optical telescope: SOFIA uses a 2.5 m (8.2 ft) reflector telescope, which has an oversized, 2.7 m (8.9 ft)...
uhoh's user avatar
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2 votes
1 answer
98 views

What telescopes used 1000+ pixel Microwave Kinetic Inductance Detectors (MKIDs) for multispectral, single photon counting (time + energy of photons)?

This excellent answer to What would “the next GAIA”-like instrument be like? Could it simply be a 3 to 5x scaled-up version of the same beautiful system? is worth a thorough read-through, but it and ...
uhoh's user avatar
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2 votes
1 answer
110 views

Where can I find a good solar irradiance chart for the infrared?

I'm trying to understand the results of the ExoMars Trace Gas Orbiter vs the Mars Express in terms of their abilities to find methane on the surface of Mars. The solution that I'm coming to is that it ...
PearsonArtPhoto's user avatar
1 vote
1 answer
134 views

How much infrared radiation is emitted by a bow shock?

Has the amount of energy being emitted from R Hydrae's bow shock been studied? If so, is there any information how much infrared radiation is emitted in any means of measurement? If the infrared ...
Bob516's user avatar
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1 vote
2 answers
248 views

How is IR spectroscopy used to determine the composition of asteroids?

I am trying to understand how spectrometers or spectroscopy can be used to calculate the surface composition of asteroids for the purposes of asteroid mining.
Stuti Sharma's user avatar
1 vote
0 answers
65 views

What do negative values on bright sources in TIRSPEC mean?

I opened a FITs image data from TIRSPEC (NIR imaging) (an HgCdTe infrared imaging sensor) on DS9 and I saw that some of the bright stars have black patches at the center (negative values). Can you ...
Rian's user avatar
  • 503
0 votes
2 answers
113 views

Reference for broader spectral lines?

I'm looking for some reference listing spectral lines outside the visible spectrum. (In particular, I'm looking for an element or compound that emits strongly in the 700-900nm range.)
feetwet's user avatar
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0 votes
1 answer
131 views

First Confirmed Visual Observation of Gravitational Lensing

Is it possible to identify the first direct observation of the gravitational lensing? What object was lensed, and where did the energy detected fall on the electromagnetic spectrum?
BigNutz's user avatar
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1 answer
106 views

Are red dwarfs (M dwarfs) known to be strong infrared sources?

If so, why? Are they known to be surrounded by large amounts of dust? Do they typically flare?
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